Semiconductor wafer manufacturing equipment

Abstract

To provide manufacturing equipment of semiconductor wafers capable of suppressing getting inability to properly grow the epitaxial layer.SOLUTION: A susceptor 50 is formed in a plate-like shape with one side 50a and the other side 50b and is placed in the cylindrical part 41 so that the one side 50a is located at the reaction chamber 20a side and the other side 50b is located at the hollow chamber 41a side. A recess 51 is formed for receiving a basic wafer 10 at the one side 50a side. The recess 51 has a size such that a gap S1 is created between the side surface 51b and the basic wafer 10. Through holes 54a and 54b are formed in the bottom portion 51a passing through the bottom portion 51a. The amount of the inert gas exhausted from the inert gas exhaust pipe is adjusted so that the pressure in the hollow chamber 41 is greater than or equal to the pressure in the reaction chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor wafer manufacturing apparatus. [Background technology]

[0002] Conventionally, a semiconductor wafer manufacturing apparatus has been proposed in which a base wafer is placed on a susceptor and heated while being rotated in a reaction chamber into which a reaction gas containing a raw material gas is introduced, thereby growing an epitaxial layer, which is a semiconductor layer, on the surface of the base wafer (see, for example, Patent Document 1).

[0003] Specifically, in this semiconductor wafer manufacturing device, a reactive gas is reacted on the front side of the base wafer to grow an epitaxial layer, and an inert gas is introduced on the back side of the base wafer to prevent the reactive gas from flowing around to the back side of the base wafer and causing roughness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-96181 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the semiconductor wafer manufacturing apparatus described above, when the reaction chamber becomes hot, the inert gas expands, causing an increase in pressure of the inert gas. Therefore, in this semiconductor wafer manufacturing apparatus, the increase in pressure of the inert gas flowing onto the backside of the semiconductor wafer may cause the base wafer to float, which may prevent the epitaxial layer from growing properly.

[0006] In view of the above, an object of the present invention is to provide a semiconductor wafer manufacturing apparatus that can prevent an epitaxial layer from being unable to grow properly. [Means for solving the problem]

[0007] In order to achieve the above object, claim 1 provides a semiconductor wafer manufacturing apparatus, comprising: a reaction chamber forming section (20) that forms a reaction chamber (20a) into which a reaction gas is introduced and in which an epitaxial layer (11) is grown on a surface (10a) of a base wafer (10); a reaction gas supply pipe (30) provided in the reaction chamber forming section that supplies the reaction gas for growing the epitaxial layer to the reaction chamber; a reaction gas exhaust pipe (70) provided in the reaction chamber forming section that exhausts unreacted gas from the reaction chamber; a susceptor (50) that is provided in the reaction chamber and on which the base wafer is placed; a rotating device (40) that has a cylindrical section (41) on one end of which the susceptor is placed, rotates the susceptor together with the base wafer, and forms a hollow chamber (41a) in a space surrounded by the cylindrical section and the susceptor; the susceptor is plate-shaped and has one surface (50a) and another surface (50b) opposite to the one surface, and is disposed in the cylindrical portion such that the one surface is located on the reaction chamber side and the other surface is located on the hollow chamber side; a recess (51) for accommodating a base wafer is formed on the one surface; the recess is sized to provide a gap (S1) between the side surface (51b) and the base wafer; through-holes (54a, 54b) are formed in the bottom (51a) so as to penetrate the bottom; and the amount of inert gas exhausted from the inert gas exhaust pipe is adjusted so that the pressure in the hollow chamber is equal to or greater than the pressure of the reaction chamber and equal to or less than a predetermined pressure. A plurality of through holes are formed, and the length of the opposing side surfaces of the through holes formed at positions away from the center of the bottom is wider than the length of the opposing side surfaces of the through holes formed on the center (SC) side of the bottom. .

[0008] In this case, the pressure in the hollow chamber is equal to or greater than the pressure in the reaction chamber and equal to or less than a predetermined pressure. Therefore, by setting the predetermined pressure at a pressure at which the base wafer does not float, the base wafer can be prevented from floating during growth of the epitaxial layer, and the epitaxial layer can be grown appropriately.

[0009] 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. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a semiconductor wafer manufacturing apparatus according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a susceptor. [Figure 3] FIG. [Figure 4] FIG. 1 is a diagram showing the relationship between time, temperature, and differential pressure. [Figure 5] FIG. 10 is a cross-sectional view of a susceptor according to a second embodiment. [Figure 6] FIG. 4 is a diagram showing simulation results regarding the differential pressure in the manufacturing apparatus according to the first embodiment. [Figure 7] FIG. 4 is a diagram showing a simulation result regarding the mass ratio in the manufacturing apparatus according to the first embodiment. [Figure 8] FIG. 10 is a diagram showing simulation results regarding the differential pressure in the manufacturing apparatus according to the second embodiment. [Figure 9] FIG. 10 is a diagram showing a simulation result regarding the mass ratio in the manufacturing apparatus according to the second embodiment. [Figure 10] FIG. 10 is a cross-sectional view of a susceptor according to a third embodiment. [Figure 11] FIG. 10 is a diagram showing simulation results regarding the differential pressure in the manufacturing apparatus according to the third embodiment. [Figure 12] FIG. 10 is a diagram showing a simulation result regarding the mass ratio in the manufacturing apparatus according to the third embodiment. [Figure 13] FIG. 10 is a cross-sectional view of a susceptor according to a fourth embodiment. [Figure 14] FIG. 11 is a diagram showing simulation results regarding the differential pressure in the manufacturing apparatus according to the fourth embodiment. [Figure 15] FIG. 10 is a diagram showing a simulation result regarding the mass ratio in the manufacturing apparatus according to the fourth embodiment. [Figure 16] FIG. 10 is a cross-sectional view of a susceptor according to a fifth embodiment. [Figure 17] FIG. 10 is a plan view of a susceptor according to a fifth embodiment. [Figure 18] FIG. 10 is a diagram showing the results of a simulation of the pressure difference when the distance from the center of the bottom to the outer edge through-hole is 65 mm. [Figure 19] FIG. 10 is a diagram showing the results of a simulation regarding the mass ratio when the distance from the center of the bottom to the outer edge through-hole is set to 65 mm. [Figure 20] FIG. 10 is a diagram showing the results of a simulation regarding the pressure difference when the distance from the center of the bottom to the outer edge through-hole is set to 70 mm. [Figure 21] FIG. 10 is a diagram showing the results of a simulation regarding the mass ratio when the distance from the center of the bottom to the outer edge through-hole is set to 70 mm. [Figure 22] FIG. 10 is a cross-sectional view of a susceptor according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiments, parts that are identical or equivalent to each other will be denoted by the same reference numerals.

[0012] (First embodiment) A first embodiment will be described with reference to the drawings. The semiconductor wafer manufacturing apparatus of this embodiment is suitable for use in, for example, growing an epitaxial layer made of silicon carbide (hereinafter simply referred to as SiC) on the surface of a base wafer to manufacture SiC wafers. Hereinafter, a semiconductor wafer manufacturing apparatus (hereinafter simply referred to as manufacturing apparatus) for manufacturing SiC wafers will be described as an example of the semiconductor wafer manufacturing apparatus.

[0013] 1, the manufacturing apparatus 1 has a chamber 20 that forms a reaction chamber 20a in which an epitaxial layer 11 serving as a semiconductor layer is grown on the surface 10a side of a base wafer 10. In this embodiment, the chamber 20 corresponds to a reaction chamber forming part that forms the reaction chamber 20a.

[0014] The chamber 20 is provided at its upper side with a reactive gas supply pipe 30 for supplying a reactive gas for growing a crystal thin film onto the surface 10a of the base wafer 10. In this embodiment, in order to epitaxially grow SiC, the reactive gas contains, for example, a source gas made of silane trichloride (SiHCl) and propane (C3H8), a carrier gas made of hydrogen and hydrogen chloride (HCl), and a dopant gas made of nitrogen (N2).

[0015] Specifically, the reactive gas supply pipe 30 is disposed above the chamber 20 so as to open at a position facing the surface 10a of the base wafer 10. As a result, the reactive gas is supplied to the reaction chamber 20a from a direction intersecting the surface 10a of the base wafer 10 (i.e., a direction approximately perpendicular to the surface 10a) toward the surface 10a of the base wafer 10. For this reason, the manufacturing apparatus 1 of this embodiment can be said to have a downflow-type gas supply structure in which the reactive gas is blown down toward the surface 10a of the base wafer 10.

[0016] Further, in the reaction chamber 20a, a rotation device 40 is disposed on the lower side, on which the base wafer 10 is disposed. In this embodiment, the base wafer 10 is disposed on a susceptor 50 disposed on the rotation device 40.

[0017] The rotating device 40 includes a cylindrical portion 41, a rotating shaft 42, and a drive unit 43. The cylindrical portion 41 is a bottomed cylindrical member that defines a hollow chamber 41a, and a susceptor 50 is disposed at the end on the open end side. The open end side of the cylindrical portion 41 is disposed so as to face the upper side of the chamber 20 (i.e., the reaction gas supply pipe 30 side). The cylindrical portion 41 (i.e., the hollow chamber 41a) is configured to introduce an inert gas, which will be described later, into the interior thereof, as will be described later in detail.

[0018] The rotating shaft 42 is a shaft that rotates by the output of the driving unit 43, and is connected to the cylindrical portion 41 so as to be rotatable integrally with the cylindrical portion 41. The driving unit 43 is composed of a motor or the like that outputs a rotational force, and rotates the rotating shaft 42. In the rotation device 40 configured in this manner, the rotating shaft 42 rotates by the output of the driving unit 43, and the cylindrical portion 41 and the susceptor 50 rotate integrally.

[0019] Since the susceptor 50 is placed in a high-temperature environment, it is made of, for example, isotropic graphite coated with SiC, and has an outer shape that matches the open end of the cylindrical portion 41. The susceptor 50 is placed at the open end of the cylindrical portion 41, thereby substantially closing the cylindrical portion 41. As a result, the hollow chamber 41a of the cylindrical portion 41 is substantially closed.

[0020] The shape of the susceptor 50 will now be described with reference to Figures 2 and 3. Figure 2 corresponds to a cross section taken along line II-II in Figure 3.

[0021] The susceptor 50 is plate-shaped and has one surface 50a and another surface 50b, and a recess 51 for accommodating the base wafer 10 is formed on the one surface 50a side. Specifically, the recess 51 is shaped to correspond to the outer shape of the base wafer 10, and has a substantially circular planar shape. In other words, the bottom 51a of the recess 51 is substantially circular. The recess 51 is also slightly larger than the base wafer 10, and is sized so that when the base wafer 10 is placed therein, a gap S1 is formed between the side surface 51b of the recess 51 and the base wafer 10.

[0022] Here, the surface of the bottom 51a located on the side of the one surface 50a of the susceptor 50 is referred to as the first surface 511a, and the surface of the bottom 51a located on the side of the other surface 50b of the susceptor 50 is referred to as the second surface 511b. The bottom 51a of the susceptor 50 is formed with support portions 52 protruding in a normal direction relative to the surface direction of the one surface 511a. In this embodiment, three support portions 52 are provided on the outer edge of the bottom 51a, and are arranged evenly spaced apart in the circumferential direction around the center SC of the bottom 51a (i.e., the susceptor 50). The base wafer 10 is placed on the support portions 52 and accommodated in the recess 51. Therefore, a space S2 is formed between the back surface 10b of the base wafer 10 and the one surface 50a of the bottom 51a of the susceptor 50.

[0023] Furthermore, the susceptor 50 has a step portion 53 formed on the other surface 50b side to be fitted into the open end of the cylindrical portion 41. The step portion 53 is fitted into the open end of the cylindrical portion 41, thereby placing the susceptor 50 in the cylindrical portion 41. That is, the susceptor 50 is placed so that the other surface 50b side is exposed to the hollow chamber 41a and the one surface 50a side is exposed to the reaction chamber 20a.

[0024] Furthermore, the susceptor 50 has through-holes 54a and 54b penetrating the bottom 51a of the recess 51. That is, the susceptor 50 has through-holes 54a and 54b communicating between the hollow chamber 41a and the space S2. In this embodiment, the through-holes 54a and 54b are cylindrical and are formed in plurality. The through-holes 54a and 54b are arranged concentrically. Hereinafter, the through-holes 54a formed inside the concentric circles are also referred to as inner edge through-holes 54a, and the through-holes 54b formed outside the concentric circles are also referred to as outer edge through-holes 54b. The support portion 52 of this embodiment is formed closer to the outer edge of the bottom 51a than the portion where the outer edge through-holes 54b are formed. In addition, the through-holes 54a and 54b of this embodiment are formed parallel to the normal to the surface directions of the first surface 511a and the second surface 511b, respectively.

[0025] 1, a heater 60 is disposed in the hollow chamber 41a as a heating device that heats the base wafer 10 from the back surface 10b side. The heater 60 is, for example, a resistance heater made of carbon, and although not shown, is connected to the control unit 110 and heated to a predetermined temperature.

[0026] A reaction gas exhaust pipe 70 is provided on the lower side of the chamber 20 to exhaust post-reaction gas and unreacted gas. The reaction gas exhaust pipe 70 is connected to a vacuum pump 80 on the side opposite the chamber 20. The reaction gas exhaust pipe 70 is also provided with a pressure detection unit 71 and a pressure adjustment valve 72 between the chamber 20 and the vacuum pump 80. The opening / closing ratio of the pressure adjustment valve 72 is adjusted based on the pressure of the pressure detection unit 71, and the reaction chamber 20a is adjusted to a predetermined pressure.

[0027] An inert gas supply pipe 90 for supplying an inert gas and an inert gas exhaust pipe 100 for exhausting the inert gas are arranged in the hollow chamber 41a. The inert gas supply pipe 90 is equipped with a mass flow controller 91, and supplies the inert gas into the hollow chamber 41a at a constant flow rate. As a result, after the inert gas is introduced into the hollow chamber 41a, the inert gas is introduced from the hollow chamber 41a into the space S2 through the through holes 54a and 54b of the susceptor 50, and the inert gas is supplied to the back surface 10b side of the base wafer 10. This prevents the reaction gas from flowing around to the back surface 10b side of the base wafer 10. Examples of the inert gas include argon.

[0028] The inert gas exhaust pipe 100 is connected to the vacuum pump 80 at a portion opposite to the hollow chamber 41a side. The inert gas exhaust pipe 100 is also provided with a pressure detection unit 101 and a pressure adjustment valve 102 between the hollow chamber 41a and the vacuum pump 80. The pressure in the hollow chamber 41a is adjusted to a predetermined pressure by adjusting the opening / closing ratio of the pressure adjustment valve 102 based on the pressure of the pressure detection unit 101. In this embodiment, the inert gas supply pipe 90 and the inert gas exhaust pipe 100 are disposed inside the cylindrical portion 41 and communicate with the hollow chamber 41a.

[0029] Here, in this embodiment, the reactive gas exhaust pipe 70 and the inert gas exhaust pipe 100 are partially connected at a position opposite the vacuum pump 80, with the pressure adjustment valves 72 and 102 sandwiched between them. The pressure detection unit 101 is disposed so as to detect the pressure difference at the connecting portion between the reactive gas exhaust pipe 70 and the inert gas exhaust pipe 100. In other words, the pressure detection unit 101 in this embodiment detects the pressure difference between the pressure inside the reaction chamber 20a and the pressure inside the hollow chamber 41a.

[0030] Although not specifically shown, a susceptor lifting device is disposed in the hollow chamber 41a to assist the transfer robot in carrying the susceptor 50, on which the base wafer 10 is placed, into the reaction chamber 20a and in carrying the susceptor 50 out of the reaction chamber 20a. This susceptor lifting device has the function of, for example, lifting the susceptor 50 and separating it from the cylindrical portion 41 when carrying out the susceptor 50, thereby handing the susceptor 50 over to the transfer robot. However, the manufacturing apparatus 1 may not necessarily be one that carries in and out the susceptor 50 on which the base wafer 10 is placed, but may instead carry in and out only the base wafer 10 without moving the susceptor 50.

[0031] Furthermore, the manufacturing apparatus 1 includes a control unit 110. The control unit 110 is configured by a microcomputer or the like including a CPU (not shown) and a storage unit configured by a non-transitory physical storage medium such as a ROM, a RAM, a flash memory, or an HDD. CPU stands for Central Processing Unit, ROM stands for Read Only Memory, RAM stands for Random Access Memory, and HDD stands for Hard Disk Drive.

[0032] The control unit 110 realizes various control operations by having the CPU read and execute various data from the storage unit. Specifically, the control unit 110 adjusts the opening / closing ratio of the pressure regulating valve 72 based on the pressure of the pressure detection unit 71 so that the pressure in the reaction chamber 20a becomes a predetermined pressure. The control unit 110 also adjusts the opening / closing ratio of the pressure regulating valve 102 so that the pressure in the hollow chamber 41a becomes equal to or greater than the pressure in the reaction chamber 20a and the pressure in the hollow chamber 41a becomes equal to or less than the predetermined pressure. In this embodiment, the control unit 110 adjusts the opening / closing ratio of the pressure regulating valve 102 based on the result of the pressure detection unit 101 because the pressure detection unit 101 is a differential pressure gauge.

[0033] Here, the predetermined pressure is a pressure in the hollow chamber 41a that does not cause the base wafer 10 to float (i.e., not separate from the susceptor 50). This predetermined pressure is changed as appropriate depending on the flow rate of the reaction gas, the mass of the base wafer 10, etc.

[0034] The above is the configuration of the manufacturing apparatus 1 in this embodiment. Next, a method for growing the epitaxial layer 11 on the surface 10a of the base wafer 10 using the above manufacturing apparatus 1 will be described.

[0035] First, in the manufacturing apparatus 1 described above, the susceptor 50 on which the base wafer 10 is placed is rotated by the rotation device 40 at, for example, 200 rpm, while the reaction chamber 20a is heated to approximately 1600 to 1750°C by the heater 60. Then, in the manufacturing apparatus 1, a reaction gas is supplied from the reaction gas supply pipe 30 to the reaction chamber 20a, and an inert gas is supplied from the inert gas supply pipe 90. This causes the inert gas to flow into the space S2 through the through holes 54a and 54b, and an epitaxial layer 11, which is a semiconductor layer, is formed on the front surface 10a side of the base wafer 10 while preventing the reaction gas from flowing around to the back surface 10b side of the base wafer 10.

[0036] In this case, in this embodiment, the pressure in the hollow chamber 41a is set to be equal to or higher than the pressure in the reaction chamber 20a. This makes it easier for the inert gas to flow from the hollow chamber 41a (i.e., the space S2) into the reaction chamber 20a through the gap S1, effectively preventing the reactive gas from entering the hollow chamber 41a (i.e., the space S2). Furthermore, the hollow chamber 41a is set to a pressure equal to or lower than a predetermined pressure at which the base wafer 10 floats due to the pressure in the hollow chamber 41a. This allows the epitaxial layer 11 to be formed without the base wafer 10 floating.

[0037] 4, in the comparative example where the pressure inside the cavity 41a is not specifically controlled, the inert gas expands as the temperature of the base wafer 10 increases (i.e., the temperature of the cavity 41a increases), and the pressure inside the cavity 41a also increases. Therefore, the pressure difference between the pressure inside the cavity 41a and the pressure inside the reaction chamber 20a increases as the temperature of the base wafer 10 increases, which may cause the base wafer 10 to float from the susceptor 50, preventing the epitaxial layer 11 from growing properly.

[0038] In contrast, in this embodiment, the opening / closing ratio of the pressure regulating valve 102 is adjusted so that the pressure in the hollow chamber 41a is equal to or greater than the pressure in the reaction chamber 20a and the differential pressure is maintained at a predetermined pressure (for example, about 50 Pa). This prevents the pressure in the hollow chamber 41a from becoming too high, causing the base wafer 10 to float from the susceptor 50, and prevents the epitaxial layer 11 from being unable to grow properly.

[0039] The inert gas is, for example, argon, but may also be helium. The inert gas has a flow rate of, for example, 6 slm, but this can be changed as appropriate. However, if the flow rate of the inert gas is too low, changing the opening / closing ratio of the pressure regulating valve 102 may result in only a small change in the exhaust volume, making it difficult for the pressure regulating valve 102 to regulate the pressure in the hollow chamber 41a. Therefore, it is preferable that the flow rate of the inert gas be at least 1 slm.

[0040] According to the present embodiment described above, the pressure in the hollow chamber 41a is equal to or greater than the pressure in the reaction chamber 20a, and is equal to or less than a predetermined pressure that does not cause the base wafer 10 to float. This prevents the base wafer 10 from floating up during growth of the epitaxial layer 11, allowing the epitaxial layer 11 to be grown in an optimal manner.

[0041] (1) In this embodiment, the through holes 54a and 54b are formed concentrically, which makes it easier to introduce the inert gas into the entire space S2.

[0042] (Second embodiment) A second embodiment will be described. This embodiment differs from the first embodiment in that the shapes of the through holes 54a and 54b are changed. As the rest of the configuration is the same as the first embodiment, a description thereof will be omitted here.

[0043] The susceptor 50 of this embodiment is configured as shown in Fig. 5. Specifically, each of the through holes 54a, 54b is formed so as to incline from the other surface 511b of the bottom 51a toward the one surface 511a toward the side surface 51b of the recess 51 (i.e., toward the outer edge of the susceptor 50). In other words, the through holes 54a, 54b are formed so that when the inert gas flows from the hollow chamber 41a into the space S2, the flow direction of the inert gas is likely to be directed toward the side surface 51b of the recess 51.

[0044] According to the present embodiment described above, the pressure in the hollow chamber 41a is equal to or greater than the pressure in the reaction chamber 20a, and is equal to or less than a predetermined pressure at which the base wafer 10 does not float, thereby achieving the same effect as the first embodiment.

[0045] (1) In this embodiment, the through holes 54a, 54b are formed so as to incline from the other surface 511b of the bottom 51a toward the one surface 511a toward the side surface 51b of the recess 51. Therefore, the inert gas flowing from the hollow chamber 41a into the space S2 tends to flow toward the side surface 51b of the recess 51 and easily flows into the reaction chamber 20a through the gap S1 between the base wafer 10 and the side surface 51b of the recess 51. Therefore, it is possible to further prevent the reaction gas from entering the back surface 10b of the base wafer 10.

[0046] Specifically, the inventors performed a simulation in which the reaction chamber 20a was heated to approximately 1600°C using the heater 60 and the epitaxial layer 11 was grown under the following conditions, obtaining the results shown in FIGS. 6 to 9. In the simulation, the pressure inside the reaction chamber 20a was kept constant at approximately 27 kPa, and the epitaxial layer 11 was grown under conditions in which the pressure in the hollow chamber 41a was approximately 50 Pa higher than the pressure in the reaction chamber 20a. Note that although the space S2 is connected to the reaction chamber 20a through the through-holes 54a and 54b, the pressure therein is lower than that of the reaction chamber 20a. In addition, in this simulation, the flow rates of the reaction gases were 3 slm of silane trichloride (SiHCl), 1 slm of propane (C3H8), 9 slm of hydrogen chloride (HCl), and 83 slm of hydrogen gas, and the flow rate of the inert gas argon (Ar) was 6 slm. 6 and 8 show the differential pressure based on the pressure in the reaction chamber 20a, and numerically show the differential pressure near the center WC on the backside 10b of the base wafer 10. Figures 7 and 9 show the mass ratio of silane trichloride.

[0047] First, in the manufacturing apparatus 1 of the first embodiment described above, in which the through holes 54a, 54b are parallel to the normal direction to one surface 511a of the bottom 51a, the results shown in Figures 6 and 7 were obtained. That is, as shown in Figure 6, it was confirmed that the pressure near the center WC on the back surface 10b of the base wafer 10 was about 25 Pa higher than the pressure in the reaction chamber 20a. Furthermore, as shown in Figure 7, it was confirmed that the mass ratio of trichlorosilane near the center WC on the back surface 10b of the base wafer 10 was 0.001 or less, which can be sufficiently lower than the mass ratio of trichlorosilane near the front surface 10a of the base wafer 10 (i.e., 0.1 or more).

[0048] On the other hand, in the manufacturing apparatus 1 of this embodiment, as shown in Fig. 8, it was confirmed that the pressure near the center WC on the back surface 10b of the base wafer 10 was about 19 Pa higher than the pressure in the reaction chamber 20a. Also, as shown in Fig. 9, it was confirmed that the mass ratio of trichlorosilane near the center WC on the back surface 10b of the base wafer 10 was 0.001 or less, which can be sufficiently lower than the mass ratio of trichlorosilane near the front surface 10a of the base wafer 10 (i.e., 0.1 or more).

[0049] That is, it is confirmed that the manufacturing apparatus 1 of this embodiment makes it easier for the inert gas to flow into the reaction chamber 20a through the gap S1 between the base wafer 10 and the side surface 51b of the recess 51.

[0050] (Third embodiment) A third embodiment will be described. This embodiment differs from the second embodiment in that the shapes of the through holes 54a and 54b are changed. As the rest of the configuration is the same as the second embodiment, a description thereof will be omitted here.

[0051] The susceptor 50 of this embodiment is configured as shown in Fig. 10. Specifically, the outer edge through-hole 54b has a longer side surface facing the inner edge through-hole 54a. In other words, the outer edge through-hole 54b has a larger diameter than the inner edge through-hole 54a. In other words, the outer edge through-hole 54b has a larger cross-sectional area than the inner edge through-hole 54a.

[0052] According to the present embodiment described above, the pressure in the hollow chamber 41a is equal to or greater than the pressure in the reaction chamber 20a, and is equal to or less than a predetermined pressure at which the base wafer 10 does not float, thereby achieving the same effect as the first embodiment.

[0053] (1) In this embodiment, the outer edge through-holes 54b have a longer side surface facing the inner edge through-holes 54a. Therefore, the inert gas flowing from the hollow chamber 41a into the space S2 is more likely to flow through the outer edge through-holes 54b near the gap S1 between the base wafer 10 and the side surface 51b of the recess 51, and is more likely to flow into the reaction chamber 20a through the gap S1. This further reduces the intrusion of the reactive gas into the back surface 10b of the base wafer 10.

[0054] Specifically, the inventors performed a simulation under the same conditions as in the second embodiment and obtained the results shown in Figures 11 and 12. Note that Figures 11 and 12 show the simulation results when the length of the opposing side surfaces of the outer edge through-holes 54b is set to twice the length of the opposing side surfaces of the inner edge through-holes 54a (i.e., the cross-sectional area of ​​the outer edge through-holes 54b is set to twice the cross-sectional area of ​​the inner edge through-holes 54a). Furthermore, Figure 11 shows the differential pressure based on the pressure in the reaction chamber 20a, and the differential pressure near the center WC on the back surface 10b of the base wafer 10 is shown numerically. Figure 12 shows the mass ratio of silane trichloride.

[0055] 11, it was confirmed that in the manufacturing apparatus 1 of this embodiment, the pressure near the center C on the back surface 10b of the base wafer 10 is about 10 Pa higher than the pressure in the reaction chamber 20a. Also, as shown in FIG. 12, it was confirmed that the mass ratio of trichlorosilane near the center C on the back surface 10b of the base wafer 10 is 0.001 or less, which can be sufficiently lower than the mass ratio of trichlorosilane near the front surface 10a of the base wafer 10 (i.e., 0.1 or more).

[0056] That is, it is confirmed that the manufacturing apparatus 1 of this embodiment makes it easier for the inert gas to flow into the reaction chamber 20a through the gap S1 between the base wafer 10 and the side surface 51b of the recess 51.

[0057] (Fourth embodiment) A fourth embodiment will be described. This embodiment is different from the third embodiment in that the shape of the susceptor 50 is changed. As the rest is the same as the third embodiment, a description thereof will be omitted here.

[0058] 13, the susceptor 50 of this embodiment has a shape in which the inner edge portion of the bottom 51a of the recess 51 bulges out toward the other surface 50b more than the outer edge portion. Therefore, when the base wafer 10 is placed in the recess 51 of the susceptor 50, the distance d1 between the center WC of the back surface 10b of the base wafer 10 and one surface 511a of the bottom 51a is wider than the distance d2 between the outer edge of the back surface 10b of the base wafer 10 and one surface 511a of the bottom 51a. In other words, the distance between the back surface 10b of the base wafer 10 and the portion of the bottom 51a where the inner edge through-hole 54a is formed is wider than the distance between the back surface 10b of the base wafer 10 and the portion of the bottom 51a where the outer edge through-hole 54b is formed.

[0059] According to the present embodiment described above, the pressure in the hollow chamber 41a is equal to or greater than the pressure in the reaction chamber 20a, and is equal to or less than a predetermined pressure at which the base wafer 10 does not float, thereby achieving the same effect as the first embodiment.

[0060] (1) In this embodiment, the bottom 51a of the susceptor 50 has a shape in which the inner edge portion bulges toward the other surface 50b more than the outer edge portion. Therefore, the distance between the back surface 10b of the base wafer 10 and the portion of the bottom 51a where the inner edge through-holes 54a are formed is wider than the distance between the back surface 10b of the base wafer 10 and the portion of the bottom 51a where the outer edge through-holes 54b are formed. Therefore, the inert gas flowing into the space S2 from the outer edge through-holes 54b is more likely to flow into the reaction chamber 20a through the gap S1 between the base wafer 10 and the side surface 51b of the recess 51. This further prevents the reactive gas from entering the back surface 10b of the base wafer 10.

[0061] Specifically, the inventors performed a simulation under the same conditions as in the third embodiment and obtained the results shown in Figures 14 and 15. Note that Figures 14 and 15 are simulation results in which the distance d1 was set to twice the distance d2. Furthermore, Figure 14 shows the differential pressure based on the pressure in the reaction chamber 20a, and the differential pressure near the center WC on the back surface 10b of the base wafer 10 is shown numerically. Figure 15 shows the mass ratio of silane trichloride in the reaction chamber 20a.

[0062] In the manufacturing apparatus 1 of this embodiment, as shown in Fig. 14, it was confirmed that the pressure near the center C on the back surface 10b of the base wafer 10 is about 8 Pa higher than the pressure in the reaction chamber 20a. Also, as shown in Fig. 15, it was confirmed that the mass ratio of trichlorosilane near the center C on the back surface 10b of the base wafer 10 is 0.001 or less, which can be sufficiently lower than the mass ratio of trichlorosilane near the front surface 10a of the base wafer 10 (i.e., 0.1 or more).

[0063] That is, it is confirmed that the manufacturing apparatus 1 of this embodiment makes it easier for the inert gas to flow into the reaction chamber 20a through the gap S1 between the base wafer 10 and the side surface 51b of the recess 51.

[0064] (Fifth embodiment) A fifth embodiment will be described. This embodiment is different from the third embodiment in that the shape of the susceptor 50 is changed. As the rest is the same as the third embodiment, a description thereof will be omitted here.

[0065] As shown in FIGS. 16 and 17 , in the susceptor 50 of this embodiment, the support portion 52 is formed in a portion of the bottom portion 51 a between the outer edge through-hole 54 b and the inner edge through-hole 54 a. In other words, the outer edge through-hole 54 b is formed in the bottom portion 51 a of the recess 51 closer to the outer edge than the support portion 52. Therefore, compared to the third embodiment, the outer edge through-hole 54 b is formed further to the outer edge of the bottom portion 51 a of the recess 51. In this embodiment, the distance from the center SC of the bottom portion 51 a to the outer edge through-hole 54 b is longer than in the third embodiment. Note that the susceptor 50 in FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. 17 .

[0066] According to the present embodiment described above, the pressure in the hollow chamber 41a is equal to or greater than the pressure in the reaction chamber 20a, and is equal to or less than a predetermined pressure at which the base wafer 10 does not float, thereby achieving the same effect as the first embodiment.

[0067] (1) In this embodiment, the outer edge through-holes 54b are formed on the bottom 51a of the recess 51 closer to the outer edge than the support portion 52. Therefore, the inert gas that flows into the space S2 from the outer edge through-holes 54b is more likely to flow into the reaction chamber 20a through the gap S1 between the base wafer 10 and the side surface 51b of the recess 51. This further prevents the reactive gas from entering the back surface 10b of the base wafer 10.

[0068] Specifically, the inventors performed a simulation under the same conditions as in the third embodiment and obtained the results shown in Figures 18 to 21. Figures 18 and 19 show the results when the distance from the center SC of the bottom 51a to the outer edge through-hole 54b was 65 mm. Figures 20 and 21 show the results when the distance from the center SC of the bottom 51a to the outer edge through-hole 54b was 70 mm.

[0069] First, in the manufacturing apparatus 1 in which the distance from the center SC of the bottom 51a to the outer edge through-hole 54b is 65 mm, it was confirmed that the pressure near the center WC on the back surface 10b of the base wafer 10 is about 18 Pa higher than the pressure in the reaction chamber 20a, as shown in Fig. 18. Furthermore, it was confirmed that the mass ratio of trichlorosilane near the center C on the back surface 10b of the base wafer 10 is 0.001 or less, which can be made sufficiently lower than the mass ratio of trichlorosilane near the front surface 10a of the base wafer 10 (i.e., 0.1 or more).

[0070] In contrast, in a manufacturing apparatus 1 in which the distance from the center SC of the bottom 51a to the outer edge through-hole 54b is 70 mm, it was confirmed that the pressure near the center WC on the back surface 10b of the base wafer 10 is about 10 Pa higher than the pressure in the reaction chamber 20a, as shown in Fig. 20. Furthermore, as shown in Fig. 21, it was confirmed that the mass ratio of trichlorosilane near the center WC on the back surface 10b of the base wafer 10 is 0.001 or less, which can be sufficiently lower than the mass ratio of trichlorosilane near the front surface 10a of the base wafer 10 (i.e., 0.1 or more).

[0071] That is, it has been confirmed that the longer the distance from the center SC of the bottom 51a to the outer edge through-hole 54b, the more easily the reaction gas flows into the reaction chamber 20a through the gap S1 between the base wafer 10 and the side surface 51b of the recess 51. For this reason, by forming the outer edge through-hole 54b closer to the outer edge than the support portion 52, as in the present embodiment, it is possible to easily increase the distance from the center SC of the bottom 51a to the outer edge through-hole 54b, and to easily allow the reaction gas to flow into the reaction chamber 20a through the gap S1.

[0072] (Sixth embodiment) A sixth embodiment will be described. This embodiment is different from the third embodiment in that the shape of the susceptor 50 is changed. As the rest is the same as the third embodiment, a description thereof will be omitted here.

[0073] As shown in Fig. 22, the susceptor 50 of this embodiment has a suppression portion 55 formed around the recess 51 on one surface 50a of the susceptor 50. Specifically, the suppression portion 55 has a protruding portion that overlaps the recess 51 in the normal direction of the one surface 50a of the susceptor 50, and is configured to be out of contact with the epitaxial layer 11 when the base wafer 10 is placed and the epitaxial layer 11 grows thereon. In this embodiment, the suppression portion 55 has a base portion 55a that extends in the normal direction of the one surface 50a and a protruding portion 55b that protrudes from the base portion 55a toward the recess 51. In this embodiment, for example, three suppression portions 55 are formed around the recess 51, and are spaced equally apart in the circumferential direction.

[0074] According to the present embodiment described above, the pressure in the hollow chamber 41a is equal to or greater than the pressure in the reaction chamber 20a, and is equal to or less than a predetermined pressure at which the base wafer 10 does not float, thereby achieving the same effect as the first embodiment.

[0075] (1) In this embodiment, a suppression unit 55 is disposed on one surface 50a of the susceptor 50. Therefore, even if the base wafer 10 floats up, the suppression unit 55 can prevent the base wafer 10 from falling from the susceptor 50, thereby preventing malfunctions of the manufacturing apparatus 1.

[0076] (Other embodiments) Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0077] For example, in each of the above embodiments, the manufacturing apparatus 1 is described as growing an SiC epitaxial layer 11. However, the configuration of the epitaxial layer 11 to be grown can be changed as appropriate, and for example, the manufacturing apparatus 1 may be configured as growing an epitaxial layer 11 of gallium nitride.

[0078] In addition, in each of the above embodiments, an example has been described in which the pressure detection unit 101, which detects the pressure in the hollow chamber 41a, detects the differential pressure between the hollow chamber 41a and the reaction chamber 20a. However, it is also possible to have the pressure detection unit 101 detect the pressure in the hollow chamber 41a and have the control unit 110 derive the differential pressure between the reaction chamber 20a and the hollow chamber 41a. However, detailed pressure management is required to prevent the reaction gas from circulating around the back surface 10b of the base wafer 10 while preventing the base wafer 10 from floating up, etc. For this reason, it is preferable that the pressure detection unit 101 directly detects the differential pressure between the reaction chamber 20a and the hollow chamber 41a.

[0079] Furthermore, in each of the above embodiments, the through holes 54a, 54b are formed concentrically, but the arrangement of the through holes 54a, 54b can be changed as appropriate.

[0080] The above-described embodiments can also be combined as appropriate. For example, in the third to sixth embodiments, the through holes 54a, 54b may be formed parallel to the normal direction to the one surface 511a of the bottom 51a, as in the first embodiment. Furthermore, the third to fifth embodiments may be combined as appropriate to further facilitate the inert gas flowing from the gap S1 into the reaction chamber 20a.

[0081] The controller and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0082] (Features of the present invention) [Claim 1] A semiconductor wafer manufacturing apparatus, a reaction chamber forming section (20) for forming a reaction chamber (20a) into which a reaction gas is introduced and in which an epitaxial layer (11) is grown on the surface (10a) of the base wafer (10); a reaction gas supply pipe (30) provided in the reaction chamber for supplying a reaction gas for growing the epitaxial layer to the reaction chamber; a reaction gas exhaust pipe (70) provided in the reaction chamber for exhausting unreacted gas from the reaction chamber; a susceptor (50) disposed in the reaction chamber on which the base wafer is placed; a rotating device (40) having a cylindrical portion (41) on one end of which the susceptor is disposed, rotating the susceptor together with the base wafer, and forming a space surrounded by the cylindrical portion and the susceptor as a hollow chamber (41a); an inert gas supply pipe (90) provided in the hollow chamber for introducing an inert gas into the hollow chamber; an inert gas exhaust pipe (100) provided in the hollow chamber for exhausting the inert gas; the susceptor is plate-shaped and has one surface (50a) and another surface (50b) opposite to the one surface, and is disposed in the cylindrical portion such that the one surface side is positioned on the reaction chamber side and the other surface side is positioned on the hollow chamber side, and a recess (51) for accommodating the base wafer is formed on the one surface side; The recess is sized to have a gap (S1) between the side surface (51b) and the base wafer, and through holes (54a, 54b) are formed in the bottom (51a) so as to penetrate the bottom, A semiconductor wafer manufacturing apparatus in which the amount of the inert gas exhausted from the inert gas exhaust pipe is adjusted so that the pressure in the hollow chamber is equal to or greater than the pressure of the reaction chamber and equal to or less than a predetermined pressure. [Claim 2] 2. The semiconductor wafer manufacturing apparatus according to claim 1, wherein the through holes are formed so that a plurality of the through holes are cylindrical and are formed concentrically with the center (SC) of the bottom portion as a reference. [Claim 3] 3. The semiconductor wafer manufacturing apparatus according to claim 1, wherein the through-holes are formed at an angle from the other surface side of the susceptor toward the one surface side toward the outer edge side of the susceptor. [Claim 4] A semiconductor wafer manufacturing apparatus as described in any one of claims 1 to 3, wherein a plurality of the through holes are formed, and the length of the opposing side of the through hole formed at a position away from the center of the bottom is wider than the length of the opposing side of the through hole formed on the center (SC) side of the bottom. [Claim 5] A support portion (52) is formed at the bottom of the recess, protruding in a normal direction relative to the surface direction of the bottom and supporting the base wafer, A semiconductor wafer manufacturing apparatus as described in any one of claims 1 to 4, wherein the bottom of the susceptor is shaped to bulge toward the other side so that when the base wafer is placed on the support, the distance (d1) between the inner edge portion of the base wafer and the susceptor is longer than the distance (d1) between the outer edge portion of the base wafer and the susceptor. [Claim 6] A support portion (52) is formed at the bottom of the recess, protruding in a normal direction relative to the surface direction of the bottom and supporting the base wafer, 6. The semiconductor wafer manufacturing apparatus according to claim 1, wherein the through-hole is formed at least closer to the outer edge of the bottom than the support portion. [Claim 7] 7. A semiconductor wafer manufacturing apparatus as described in any one of claims 1 to 6, wherein the susceptor has a protruding portion in a portion of the one surface located around the recess so as to overlap the recess in the normal direction of the one surface, and is provided with a suppression portion (55) configured to be out of contact with the epitaxial layer when the epitaxial layer is grown on the base wafer. [Explanation of symbols]

[0083] 10 Base Wafer 10a surface 20 Chamber (reaction chamber forming part) 20a Reaction chamber 30 Reaction gas supply pipe 40 Rotating Device 41 Cylinder part 41a Hollow chamber 50 susceptors 50a One side 50b other side 51 Recess 51a bottom 51b Side 90 Inert gas supply pipe 100 Inert gas exhaust pipe S1 Gap

Claims

1. A semiconductor wafer manufacturing apparatus, a reaction chamber forming section (20) for forming a reaction chamber (20a) into which a reaction gas is introduced and in which an epitaxial layer (11) is grown on the surface (10a) of the base wafer (10); a reaction gas supply pipe (30) provided in the reaction chamber for supplying a reaction gas for growing the epitaxial layer to the reaction chamber; a reaction gas exhaust pipe (70) provided in the reaction chamber for exhausting unreacted gas from the reaction chamber; a susceptor (50) disposed in the reaction chamber and on which the base wafer is placed; a rotating device (40) having a cylindrical portion (41) on one end of which the susceptor is disposed, rotating the susceptor together with the base wafer, and forming a hollow chamber (41 a) in a space surrounded by the cylindrical portion and the susceptor; an inert gas supply pipe (90) provided in the hollow chamber for introducing an inert gas into the hollow chamber; an inert gas exhaust pipe (100) provided in the hollow chamber for exhausting the inert gas; The susceptor is plate-shaped and has one surface (50a) and another surface (50b) opposite to the one surface, and is disposed in the cylindrical portion such that the one surface side is located on the reaction chamber side and the other surface side is located on the hollow chamber side, and a recess (51) for accommodating the base wafer is formed on the one surface side, The recess is sized to have a gap (S1) between the side surface (51b) and the base wafer, and through holes (54a, 54b) are formed in the bottom (51a) to penetrate the bottom, the amount of the inert gas exhausted from the inert gas exhaust pipe is adjusted so that the pressure in the hollow chamber is equal to or higher than the pressure of the reaction chamber and equal to or lower than a predetermined pressure; A semiconductor wafer manufacturing apparatus in which multiple through holes are formed, and the length of the opposing side of the through hole formed at a position away from the center of the bottom is wider than the length of the opposing side of the through hole formed on the center (SC) side of the bottom.

2. 2. The semiconductor wafer manufacturing apparatus according to claim 1, wherein the through holes are formed so that a plurality of the through holes are cylindrical and are formed concentrically with the center (SC) of the bottom portion as a reference.

3. 2. The semiconductor wafer manufacturing apparatus according to claim 1, wherein the through-holes are formed at an angle from the other surface side of the susceptor toward the one surface side toward the outer edge of the susceptor.

4. A support portion (52) is formed at the bottom of the recess, protruding in a normal direction relative to the surface direction of the bottom and supporting the base wafer; The semiconductor wafer manufacturing apparatus described in 1, wherein the susceptor has a bottom that bulges out toward the other side so that when the base wafer is placed on the support, the distance (d1) between the inner edge portion of the base wafer and the susceptor is longer than the distance (d2) between the outer edge portion of the base wafer and the susceptor.

5. A support portion (52) is formed at the bottom of the recess, protruding in a normal direction relative to the surface direction of the bottom and supporting the base wafer; 2. The semiconductor wafer manufacturing apparatus according to claim 1, wherein the through-hole is formed at least closer to the outer edge of the bottom than the support portion.

6. 2. The semiconductor wafer manufacturing apparatus of claim 1, wherein the susceptor has a protruding portion in a portion of the one surface located around the recess so as to overlap the recess in the normal direction of the one surface, and is provided with a suppression portion (55) configured to be out of contact with the epitaxial layer when the epitaxial layer is grown on the base wafer.

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