Dry etching apparatus and semiconductor substrate manufacturing method

Abstract

To provide a dry etching device and a manufacturing method of a semiconductor substrate capable of making the distribution of etching rates in a semiconductor substrate close to rotationally symmetrical.SOLUTION: A dry etching device includes a chamber, a substrate holder, and a plurality of vent pipes. An exhaust port is provided in the chamber. The substrate holder is located within the chamber. The substrate holder is spaced apart from the chamber. The plurality of vent pipes is supported by the chamber. The exhaust port intersects the central axis of the substrate holder. An internal space is provided in the substrate holder. At least one of the plurality of vent pipes connects the interior space to the exterior of the chamber. The substrate holder is supported by the plurality of vent pipes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a dry etching apparatus and a method for manufacturing a semiconductor substrate. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2000-299312 (Patent Document 1) discloses a dry etching apparatus in which an exhaust pipe is provided on the side of a vacuum processing chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-299312 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a dry etching apparatus and a method for manufacturing a semiconductor substrate that can approximate the distribution of etching rates on a semiconductor substrate to rotational symmetry. [Means for solving the problem]

[0005] The dry etching apparatus of the present disclosure includes a chamber, a substrate holding part, and a plurality of ventilation pipes. The chamber is provided with an exhaust port. The substrate holding part is located within the chamber. The substrate holding part is spaced apart from the chamber. The plurality of ventilation pipes are supported by the chamber. The exhaust port intersects with a central axis of the substrate holding part. An internal space is provided in the substrate holding part. At least one of the plurality of ventilation pipes connects the internal space to the outside of the chamber. The substrate holding part is supported by the plurality of ventilation pipes. [Effects of the Invention]

[0006] According to the present disclosure, the distribution of etching rates on a semiconductor substrate can be made closer to rotational symmetry. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view showing the configuration of a dry etching apparatus according to this embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view showing the region occupied by the exhaust flow path in the cross section shown in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view showing the area occupied by a plurality of vent pipes in the cross section shown in FIG. [Figure 5] FIG. 5 is a schematic vertical cross-sectional view showing the detailed configuration of the substrate holding unit. [Figure 6] FIG. 6 is a flow diagram that schematically shows a method for manufacturing a semiconductor substrate according to this embodiment. [Figure 7] FIG. 7 is a schematic vertical cross-sectional view showing the step of arranging the substrate. [Figure 8] FIG. 8 is a schematic vertical cross-sectional view showing the process of performing plasma etching. [Figure 9] FIG. 9 is a schematic vertical cross-sectional view showing the step of carrying out the substrate. [Figure 10] FIG. 10 is a schematic plan view showing the measurement positions of the etching rate. [Figure 11] FIG. 11 is a diagram showing the relationship between the etching rate and the distance from the center of the main surface in the example. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0009] (1) A dry etching apparatus 100 according to the present disclosure includes a chamber 2, a substrate holding unit 1, and a plurality of ventilation pipes 3. An exhaust port 29 is provided in the chamber 2. The substrate holding unit 1 is located within the chamber 2. The substrate holding unit 1 is spaced apart from the chamber 2. The plurality of ventilation pipes 3 are supported by the chamber 2. The exhaust port 29 intersects with a central axis O of the substrate holding unit 1. An internal space 51 is provided in the substrate holding unit 1. At least one of the plurality of ventilation pipes 3 connects the internal space 51 to the outside of the chamber 2. The substrate holding unit 1 is supported by the plurality of ventilation pipes 3.

[0010] (2) According to the dry etching apparatus 100 of (1) above, each of the plurality of vent pipes 3 may be positioned rotationally symmetrically with respect to the central axis O.

[0011] (3) In the dry etching apparatus 100 according to (1) or (2) above, the chamber 2 may have an inner circumferential surface 22. The inner circumferential surface 22 may be connected to each of the plurality of vent pipes 3. The substrate holder 1 may have an outer circumferential surface 11. The outer circumferential surface 11 may be connected to each of the plurality of vent pipes 3. The outer circumferential surface 11 may face the inner circumferential surface 22. At any position on the inner circumferential surface 22 between adjacent vent pipes among the plurality of vent pipes 3, the distance H2 between the inner circumferential surface 22 and the outer circumferential surface 11 in the direction perpendicular to the central axis O may be equal.

[0012] (4) In the dry etching apparatus 100 according to any one of (1) to (3) above, an exhaust flow path 37 may be formed between adjacent ones of the plurality of vent pipes 3. In a cross section perpendicular to the central axis O and in which the cross-sectional area of ​​the plurality of vent pipes 3 is maximum, the value obtained by dividing the cross-sectional area of ​​the plurality of vent pipes 3 by the area of ​​the exhaust flow path 37 may be less than 0.5.

[0013] (5) In the dry etching apparatus 100 according to (4) above, the shape of the exhaust flow path 37 may be rotationally symmetric with respect to the central axis O.

[0014] (6) The dry etching apparatus 100 according to any one of (1) to (5) above may further include at least one pipe connected to the substrate holder 1. The plurality of vent pipes 3 may include a first vent pipe 31. The at least one pipe may be located inside the first vent pipe 31.

[0015] (7) According to the dry etching apparatus 100 of (6) above, the at least one pipe may include a first pipe 41. The first pipe 41 may supply a coolant to the substrate holder 1.

[0016] (8) According to the dry etching apparatus 100 of (6) or (7) above, at least one of the pipes may include a second pipe 42. The second pipe 42 may supply a low dew point gas to the internal space 51.

[0017] (9) According to the dry etching apparatus 100 of (8) above, the plurality of vent pipes 3 may further include a second vent pipe 32. The second vent pipe 32 may exhaust the low dew point gas from the internal space 51 to the outside of the chamber 2. The second vent pipe 32 may be different from the first vent pipe 31.

[0018] (10) The dry etching apparatus 100 according to any one of (6) to (9) above may further include an electrical wiring 44. The electrical wiring 44 may be configured with a cable or a bus bar. The electrical wiring 44 may be connected to the electrode 15 of the substrate holder 1. The plurality of vent pipes 3 may further include a third vent pipe 33. The third vent pipe 33 may be different from the first vent pipe 31. The electrical wiring 44 may be located inside the third vent pipe 33.

[0019] (11) According to the dry etching apparatus 100 of any one of (1) to (10) above, the substrate holder 1 may have a substrate mounting portion 61. The diameter D1 of the substrate mounting portion 61 may be 90 mm or more.

[0020] (12) The dry etching apparatus 100 according to any one of (1) to (11) above may further include a substrate lifting unit 4. The substrate lifting unit 4 may be located in the internal space 51.

[0021] (13) In the dry etching apparatus 100 according to any one of the above (1) to (12), the substrate holder 1 may be supported only by a plurality of ventilation pipes 3.

[0022] (14) According to a method for manufacturing a semiconductor substrate 110 according to the present disclosure, the dry etching apparatus 100 according to any one of (1) to (13) above is used. The method for manufacturing a semiconductor substrate 110 according to the present disclosure includes the following steps: A substrate 80 is placed on a substrate holder 1. Plasma etching is performed on the substrate 80.

[0023] (15) According to the method for manufacturing the semiconductor substrate 110 in accordance with (14) above, the substrate 80 may be made of silicon carbide.

[0024] (16) According to the method for manufacturing the semiconductor substrate 110 according to (14) or (15) above, the substrate 80 may have an epitaxial layer.

[0025] [Details of the embodiments of the present disclosure] Hereinafter, details of an embodiment of the present disclosure (hereinafter also referred to as the present embodiment) will be described with reference to the drawings. Note that the same or corresponding parts in the following drawings will be given the same reference numerals, and their description will not be repeated. In the crystallographic descriptions in this specification, individual orientations are indicated by [ ], collective orientations by < >, individual planes by ( ), and collective planes by {}. Furthermore, for negative indices, in crystallography, a "-" (bar) is placed before the number, but in this specification, a negative sign is placed before the number.

[0026] (Dry etching equipment) First, the configuration of the dry etching apparatus according to this embodiment will be described. Fig. 1 is a cross-sectional view showing the configuration of the dry etching apparatus according to this embodiment.

[0027] As shown in FIG. 1, the dry etching apparatus 100 according to this embodiment mainly includes a substrate holder 1, a chamber 2, a spacer flange 7, a gas ring 6, an upper electrode 25, a plurality of vent pipes 3, a plurality of pipes 30, a substrate lifting unit 4, a conductance control valve 8, a rectifier plate 9, a high-frequency power supply 91, a microwave power supply 92, a first electrical wiring 44, and a second electrical wiring 45.

[0028] The substrate holder 1 holds a substrate 80. The chamber 2 surrounds the substrate holder 1. From another perspective, the substrate holder 1 is located within the chamber 2. The substrate holder 1 is spaced apart from the chamber 2. The chamber 2, the spacer flange 7, the gas ring 6, and the upper electrode 25 are combined into a box shape. The space surrounded by the chamber 2, the spacer flange 7, the gas ring 6, and the upper electrode 25, and outside the substrate holder 1, is the processing space 52. In the processing space 52, plasma is generated, and plasma etching is performed on the substrate 80.

[0029] The substrate holder 1 has a cylindrical shape. The central axis of the substrate holder 1 is set as a central axis O. The substrate holder 1 is substantially rotationally symmetric with respect to the central axis O, for example.

[0030] The substrate holder 1 has a housing portion 10 and a lower electrode 15. The housing portion 10 has a first cylindrical portion 18 and a first bottom portion 17. The first cylindrical portion 18 has a first outer peripheral surface 11 and a first inner peripheral surface 12. The first outer peripheral surface 11 faces the chamber 2. The first inner peripheral surface 12 is on the opposite side of the first outer peripheral surface 11. The first bottom portion 17 is continuous with the first cylindrical portion 18.

[0031] The lower electrode 15 is located on the housing 10. The lower electrode 15 has a top surface 13 and a bottom surface 14. At the bottom surface 14, the lower electrode 15 contacts the first cylindrical portion 18 of the housing 10. The top surface 13 is located opposite the bottom surface 14. The top surface 13 is circular. As shown in FIG. 1 , the center of the top surface 13 may be located on the central axis O.

[0032] 1, an internal space 51 is provided in the substrate holding part 1. Specifically, the internal space 51 is formed by each of the accommodation part 10 and the lower electrode 15. The internal space 51 is a space different from the processing space 52.

[0033] The chamber 2 is, for example, substantially rotationally symmetrical with respect to the central axis O. The chamber 2 has a second cylindrical portion 28 and a second bottom portion 27.

[0034] The second cylindrical portion 28 has a second inner peripheral surface 22 and a second outer peripheral surface 21. The second inner peripheral surface 22 faces the first outer peripheral surface 11 of the accommodation portion 10. The second inner peripheral surface 22 surrounds the first outer peripheral surface 11. The second outer peripheral surface 21 is on the opposite side of the second inner peripheral surface 22. The second bottom portion 27 is continuous with the second cylindrical portion 28. The second cylindrical portion 28 is spaced apart from the substrate holding portion 1. The second bottom portion 27 is spaced apart from the substrate holding portion 1. The second bottom portion 27 faces the first bottom portion 17 of the substrate holding portion 1.

[0035] An exhaust port 29 is provided in the second bottom 27. The exhaust port 29 intersects with the central axis O. From another perspective, the exhaust port 29 and the substrate holder 1 are positioned coaxially. In other words, the dry etching apparatus 100 has a coaxial exhaust structure. In the axial direction, the substrate holder 1 is positioned above the exhaust port 29. Note that in this specification, the axial direction means a direction parallel to the central axis O. The diameter of the exhaust port 29 may be larger than the diameter of the substrate holder 1. A conductance control valve 8 is attached to the exhaust port 29. The conductance control valve 8 controls the exhaust flow rate from the processing space 52 to the outside of the chamber 2.

[0036] The spacer flange 7 is located on the chamber 2. The spacer flange 7 is in contact with the chamber 2. The spacer flange 7 is cylindrical. The spacer flange 7 can change the distance between the upper electrode 25 and the lower electrode 15 in the axial direction (hereinafter referred to as the first distance H1). Specifically, the first distance H1 can be changed by replacing the spacer flange 7 with a spacer flange 7 having a different thickness in the axial direction.

[0037] The gas ring 6 is positioned on the spacer flange 7. From another perspective, the spacer flange 7 is positioned between the chamber 2 and the gas ring 6. The gas ring 6 is in contact with the spacer flange 7. The gas ring 6 supplies a process gas to the processing space 52. The process gas is, for example, a fluorine-based gas. The gas ring 6 is provided with a gas flow path 35 and a plurality of outlets 36. The gas flow path 35 is circumferential. The gas flow path 35 is connected to the processing space 52 via the plurality of outlets 36.

[0038] The upper electrode 25 is located on the gas ring 6. From another perspective, the gas ring 6 is located between the spacer flange 7 and the upper electrode 25. The upper electrode 25 is in contact with the gas ring 6. The upper electrode 25 faces the top surface 13 of the lower electrode 15.

[0039] 1, the multiple vent pipes 3 include a first vent pipe 31 and a third vent pipe 33. Each of the multiple vent pipes 3 is connected to the substrate holding unit 1 and the chamber 2. Specifically, each of the first vent pipe 31 and the third vent pipe 33 is connected to the first outer peripheral surface 11 of the storage unit 10 and the second inner peripheral surface 22 of the chamber 2, respectively. As shown in FIG. 1, each of the multiple vent pipes 3 may be located at the same height in the axial direction.

[0040] The substrate holding unit 1 is supported in the chamber 2 using a plurality of ventilation pipes 3. In other words, the substrate holding unit 1 is supported by a plurality of ventilation pipes 3. The substrate holding unit 1 may be supported only by a plurality of ventilation pipes 3. Each of the plurality of ventilation pipes 3 is supported in the chamber 2. The diameter of each of the plurality of ventilation pipes 3 is, for example, 10 mm or more and 50 mm or less.

[0041] At least one of the multiple ventilation pipes 3 connects the internal space 51 to the outside of the chamber 2. The outside of the chamber 2 is, for example, atmospheric space. In other words, the internal space 51 is connected to atmospheric space. The internal space 51 and the interior of each of the multiple ventilation pipes 3 are isolated from the processing space 52. Specifically, the internal space 51 and the interior of each of the multiple ventilation pipes 3 are isolated from the processing space 52 by the substrate holder 1 and the multiple ventilation pipes 3.

[0042] The substrate lifting / lowering unit 4 is located in the internal space 51 of the substrate holding unit 1. The substrate lifting / lowering unit 4 is in contact with the first bottom 17 of the accommodation unit 10. The substrate lifting / lowering unit 4 lifts the substrate 80. The substrate lifting / lowering unit 4 is, for example, an air cylinder or the like.

[0043] 1, the multiple pipes 30 include a first pipe 41, a second pipe 42, and a third pipe 43. Each of the multiple pipes 30 extends from the outside of the chamber 2 through the first ventilation pipe 31 to the internal space 51 of the substrate holder 1. In other words, each of the multiple pipes 30 is located inside the first ventilation pipe 31.

[0044] Each of the multiple tubes 30 is connected to the substrate holder 1. Specifically, one end of the first tube 41 is connected to the lower electrode 15 of the substrate holder 1. One end of the second tube 42 is located in the internal space 51 of the substrate holder 1. One end of the third tube 43 is connected to the top surface 13 of the lower electrode 15. From another perspective, a portion of the third tube 43 is located within the lower electrode 15.

[0045] The first pipe 41 supplies a coolant to the substrate holding unit 1. Specifically, the first pipe 41 supplies the coolant into the lower electrode 15 of the substrate holding unit 1. In other words, the first pipe 41 cools the lower electrode 15. The coolant is, for example, water or a cooling liquid such as Galden (registered trademark).

[0046] The second pipe 42 supplies a low dew point gas to the internal space 51 of the substrate holder 1. In other words, the second pipe 42 supplies a gas that prevents condensation in the internal space 51. The low dew point gas is, for example, nitrogen gas or dry air.

[0047] The third tube 43 supplies helium gas to the substrate holder 1. Specifically, the helium gas is supplied between the top surface 13 of the lower electrode 15 and the substrate 80. The helium gas cools the substrate 80 by heat transfer. In other words, the third tube 43 cools the substrate 80.

[0048] The first electrical wiring 44 connects the high-frequency power supply 91 and the lower electrode 15. In other words, the first electrical wiring 44 is connected to the lower electrode 15 of the substrate holding unit 1. The first electrical wiring 44 extends from the outside of the chamber 2 through the third ventilation pipe 33 to the internal space 51 of the substrate holding unit 1. In other words, the first electrical wiring 44 is located inside the third ventilation pipe 33. The first electrical wiring 44 is formed, for example, by a cable or a bus bar. The high-frequency power supply 91 supplies power to the lower electrode 15 via the first electrical wiring 44.

[0049] The second electrical wiring 45 connects the microwave power supply 92 and the upper electrode 25. In other words, the second electrical wiring 45 is connected to the upper electrode 25. The microwave power supply 92 supplies power to the upper electrode 25 via the second electrical wiring 45.

[0050] The rectifying plate 9 is in contact with both the substrate holder 1 and the chamber 2. In the axial direction, the rectifying plate 9 is located above the multiple vent pipes 3. The rectifying plate 9 has multiple through holes extending in the thickness direction. The multiple through holes of the rectifying plate 9 may be located rotationally symmetrically with respect to the central axis O. The diameter of each of the multiple through holes is, for example, 6 mm. The rectifying plate 9 regulates the flow of the exhausted process gas.

[0051] The dry etching apparatus 100 may be substantially rotationally symmetrical with respect to the central axis O. Specifically, each of the substrate holder 1, the chamber 2, the spacer flange 7, the gas ring 6, and the upper electrode 25 may be substantially rotationally symmetrical with respect to the central axis O. The centers of each of the substrate holder 1, the chamber 2, the spacer flange 7, the gas ring 6, and the upper electrode 25 may be located on the central axis O. The cross section shown in FIG. 1 is parallel to the central axis O and passes through the central axis O, the first vent pipe 31, and the third vent pipe 33.

[0052] Fig. 2 is a schematic cross-sectional view taken along line II-II in Fig. 1. The cross section shown in Fig. 2 is perpendicular to the central axis O and is a cross section in which the cross-sectional area of ​​the multiple vent pipes 3 is at its maximum. For ease of explanation, Fig. 2 only shows the substrate holder 1, chamber 2, and multiple vent pipes 3. In other words, Fig. 2 does not show the multiple pipes 30, the substrate lifting unit 4, the first electrical wiring 44, etc.

[0053] 2, the multiple ventilation pipes 3 further include a second ventilation pipe 32 and a fourth ventilation pipe 34. The second ventilation pipe 32 and the fourth ventilation pipe 34 are each connected to the first outer peripheral surface 11 of the substrate holding unit 1 and the second inner peripheral surface 22 of the chamber 2, respectively. As shown in FIG. 2, the first ventilation pipe 31, the second ventilation pipe 32, the third ventilation pipe 33, and the fourth ventilation pipe 34 are different from one another.

[0054] Each of the multiple vent pipes 3 may be positioned substantially rotationally symmetrical with respect to the central axis O. From another perspective, when viewed in the axial direction, each of the multiple vent pipes 3 extends radially around the central axis O. The angle θ formed between two adjacent vent pipes among the multiple vent pipes 3 is, for example, 90°.

[0055] The second vent pipe 32 may exhaust the low dew point gas from the internal space 51 to the outside of the chamber 2. From another perspective, the low dew point gas supplied to the internal space 51 by the second pipe 42 (see FIG. 1 ) is exhausted to the outside of the chamber 2 through the second vent pipe 32. A cover may be attached to the end of each of the first vent pipe 31, the third vent pipe 33, and the fourth vent pipe 34 that is close to the chamber 2. In other words, each of the first vent pipe 31, the third vent pipe 33, and the fourth vent pipe 34 does not have to exhaust the low dew point gas. From another perspective, it is sufficient that gas can be exhausted from at least one of the multiple vent pipes 3, and it is not necessary that gas be exhausted from all of the vent pipes.

[0056] 2, an exhaust flow path 37 is formed between adjacent ones of the plurality of ventilation pipes 3. Specifically, the exhaust flow path 37 is formed by each of the plurality of ventilation pipes 3, the first outer peripheral surface 11 of the substrate holder 1, and the second inner peripheral surface 22 of the chamber 2. The shape of the exhaust flow path 37 may be substantially rotationally symmetrical with respect to the central axis O. As shown in FIGS. 1 and 2, the exhaust flow path 37 serves as a flow path for the process gas supplied from the gas ring 6.

[0057] The distance between the second inner circumferential surface 22 and the first outer circumferential surface 11 in the direction perpendicular to the central axis O is set to be a second distance H2. Among the multiple ventilation pipes 3, the second distance H2 may be equal at any position on the second inner circumferential surface 22 between adjacent ventilation pipes.

[0058] Fig. 3 is a schematic cross-sectional view showing the area occupied by the exhaust flow path 37 in the cross section shown in Fig. 2. Fig. 4 is a schematic cross-sectional view showing the area occupied by a plurality of ventilation pipes 3 in the cross section shown in Fig. 2. The schematic cross-sectional views shown in each of Fig. 3 and Fig. 4 correspond to the schematic cross-sectional view shown in Fig. 2.

[0059] In Fig. 3, the area indicated by multiple dots indicates the area occupied by the exhaust flow path 37. In other words, when viewed from a direction parallel to the central axis O, the area of ​​the exhaust flow path 37 is the area of ​​the area indicated by the multiple dots in Fig. 3. In Fig. 4, the area indicated by multiple dots indicates the area occupied by the multiple vent pipes 3. In other words, in a cross section perpendicular to the central axis O and where the cross-sectional area of ​​the multiple vent pipes 3 is maximum, the cross-sectional area of ​​the multiple vent pipes 3 is the area of ​​the area indicated by the multiple dots in Fig. 4. Specifically, the cross-sectional area of ​​the multiple vent pipes 3 is the area of ​​the area including the multiple vent pipes 3 themselves and the interior of each of the multiple vent pipes 3.

[0060] As shown in Figures 3 and 4, the cross-sectional area of ​​the multiple vent pipes 3 is smaller than the area of ​​the exhaust flow path 37 when viewed in a direction parallel to the central axis O (axial direction). When viewed in the axial direction, the value obtained by dividing the cross-sectional area of ​​the multiple vent pipes 3 by the area of ​​the exhaust flow path 37 is less than 0.5. There is no particular upper limit to the value obtained by dividing the cross-sectional area of ​​the multiple vent pipes 3 by the area of ​​the exhaust flow path 37 when viewed in the axial direction, but it may be, for example, less than 0.4 or less than 0.3. When viewed in the axial direction, the value obtained by dividing the cross-sectional area of ​​the multiple vent pipes 3 by the area of ​​the exhaust flow path 37 may be, for example, 0.1 or more, or 0.2 or more.

[0061] Fig. 5 is a schematic vertical cross-sectional view showing the detailed configuration of the substrate holding unit 1. The schematic vertical cross-sectional view shown in Fig. 5 corresponds to the schematic vertical cross-sectional view shown in Fig. 1. For ease of explanation, Fig. 5 shows only the substrate holding unit 1 and multiple ventilation pipes 3.

[0062] 5, the substrate holder 1 has a metal member 70, an insulating member 73, a coolant circulation member 74, a substrate gripping member 75, and a cover member 76. The metal member 70 and the insulating member 73 form the accommodation unit 10. The coolant circulation member 74 and the substrate gripping member 75 may form the lower electrode 15.

[0063] The metal member 70 has a first portion 71 and a second portion 72. The first portion 71 is connected to each of the multiple ventilation pipes 3. The first portion 71 is cylindrical with a bottom. The second portion 72 is connected to the first portion 71. The second portion 72 is cylindrical. In the radial direction, the thickness of the second portion 72 is greater than the thickness of the first portion 71. In other words, the difference between the outer diameter and the inner diameter of the second portion 72 is greater than the difference between the outer diameter and the inner diameter of the first portion 71. In this specification, the radial direction means the radial direction relative to the central axis O. The metal member 70 is made of a metal material such as stainless steel.

[0064] The insulating member 73 is located on the metal member 70. The insulating member 73 is in contact with the metal member 70. The insulating member is cylindrical. The insulating member 73 is made of an insulating ceramic material such as Macol (trademark) or an insulating resin material such as PEEK (Poly Ether Ether Ketone). The insulating member 73 electrically insulates the lower electrode 15 and the metal member 70.

[0065] The refrigerant circulation member 74 is located above the insulating member 73. From another perspective, the insulating member 73 is located between the refrigerant circulation member 74 and the metal member 70. The refrigerant circulation member 74 is in contact with the insulating member 73. The refrigerant circulation member 74 is cylindrical. The refrigerant circulation member 74 is made of a metal material such as aluminum. A flow path (not shown) is provided inside the refrigerant circulation member 74. The refrigerant supplied from the first pipe 41 (see FIG. 1) flows through the flow path inside the refrigerant circulation member 74.

[0066] The substrate gripping member 75 is located above the coolant circulation member 74. From another perspective, the coolant circulation member 74 is located between the insulating member 73 and the substrate gripping member 75. The substrate gripping member 75 is in contact with the coolant circulation member 74. The substrate gripping member 75 is made of a metal material such as aluminum. The substrate gripping member 75 has a gripping mechanism that uses an electrostatic force, such as an electrostatic chuck, or a mechanical gripping mechanism that uses movable parts.

[0067] The substrate gripping member 75 is composed of a base portion 62 and a substrate mounting portion 61. The base portion 62 is in contact with the refrigerant circulation member 74. The base portion 62 is cylindrical. The substrate mounting portion 61 is located on the base portion 62. The substrate mounting portion 61 is connected to the base portion 62. The substrate mounting portion 61 supports a substrate 80. The center of the substrate mounting portion 61 may be on the central axis O.

[0068] The diameter of the substrate mounting portion 61 (hereinafter referred to as the first diameter D1) is, for example, 100 mm. The first diameter D1 of the substrate mounting portion 61 may be, for example, 90 mm or more. The first diameter D1 of the substrate mounting portion 61 can be changed depending on the size of the mounting substrate. There are no particular limitations on the lower and upper limits of the first diameter D1 of the substrate mounting portion 61. The first diameter D1 of the substrate mounting portion 61 is smaller than the diameter of the base portion 62.

[0069] 5, the cover member 76 covers a portion of the metal member 70, the insulating member 73, the coolant circulation member 74, and the base portion 62 of the substrate gripping member 75. The substrate mounting portion 61 is exposed from the cover member 76. The cover member 76 is cylindrical. The cover member 76 is made of, for example, quartz. The dry etching apparatus 100 is used, for example, as a plasma etching apparatus.

[0070] (Method of manufacturing semiconductor substrate) Next, a method for manufacturing a semiconductor substrate will be described. Fig. 6 is a flow diagram that schematically shows a method for manufacturing a semiconductor substrate according to this embodiment. As shown in Fig. 6, the method for manufacturing a semiconductor substrate according to this embodiment mainly includes a step (S10) of placing a substrate, a step (S20) of performing plasma etching, and a step (S30) of unloading the substrate.

[0071] First, the step of placing a substrate (S10) is performed. FIG. 7 is a schematic vertical cross-sectional view showing the step of placing a substrate. The schematic vertical cross-sectional view shown in FIG. 7 corresponds to the schematic vertical cross-sectional view shown in FIG. 1. As shown in FIG. 7, a substrate 80 is placed on the top surface 13 of the lower electrode 15. Specifically, the substrate 80 is placed on the substrate mounting portion 61 of the substrate holder 1 (see FIG. 5). The substrate 80 faces the upper electrode 25. The center of the substrate 80 may be located on the central axis O. The substrate holder 1 fixes the substrate 80 using electrostatic force.

[0072] The diameter of the substrate 80 (hereinafter referred to as the second diameter D2) is, for example, 100 mm. The substrate 80 is a semiconductor. A wiring pattern and a mask material may be provided on the substrate 80. Each of the wiring pattern and the mask material may be made of metal or resist. Each of the wiring pattern and the mask material is to be etched. The substrate 80 is made of, for example, silicon carbide (SiC). The substrate 80 may be made of, for example, silicon (Si). The substrate 80 is in contact with the substrate holder 1. The substrate 80 faces the upper electrode 25. An epitaxial layer may be provided on the substrate 80. As described above, in the substrate placement step (S10), the substrate 80 is placed on the substrate holder 1.

[0073] Next, a plasma etching step (S20) is performed. FIG. 8 is a schematic vertical cross-sectional view showing the plasma etching step. The schematic vertical cross-sectional view shown in FIG. 8 corresponds to the schematic vertical cross-sectional view shown in FIG. 1. As shown in FIG. 8, a process gas is supplied in the direction of arrow A1 using a gas ring 6. The direction of arrow A1 is from the radial outside to the radial inside.

[0074] Under low-pressure conditions, a voltage is applied to each of the upper electrode 25 and the lower electrode 15 to convert the process gas into plasma. This generates plasma in the processing space 52. After the plasma is generated under low-pressure conditions, the conductance control valve 8 is fully opened. This further reduces the pressure in the processing space 52. The pressure in the processing space 52 is reduced to, for example, 10 mTorr, or approximately 1.3 Pa. In other words, the processing space 52 is placed in a vacuum state. By supplying the process gas from the gas ring 6 while exhausting the process gas from the exhaust port 29, the pressure in the processing space 52 is maintained at approximately 1.3 Pa. When the conductance control valve 8 is fully opened, the effect of the conductance control valve 8 on the flow of the process gas can be reduced compared to when the conductance control valve 8 is not fully opened.

[0075] The plasma-converted process gas etches the substrate 80. The process gas flows in the direction of arrow A2, which is from the inside to the outside in the radial direction. In other words, the flow of the process gas over the substrate 80 is substantially rotationally symmetric when viewed in the axial direction.

[0076] The process gas is exhausted from exhaust port 29 along arrow A3. Specifically, the process gas is exhausted by passing through the multiple through holes in rectifier plate 9, exhaust flow path 37 (see FIG. 2), exhaust port 29, and conductance control valve 8 in that order. From another perspective, the process gas is exhausted along the axial direction. As described above, in the step (S20) of performing plasma etching, plasma etching is performed on substrate 80.

[0077] Next, the step of unloading the substrate (S30) is carried out. Figure 9 is a schematic vertical cross-sectional view showing the step of unloading the substrate. The schematic vertical cross-sectional view shown in Figure 9 corresponds to the schematic vertical cross-sectional view shown in Figure 1. As shown in Figure 9, the dry etching apparatus 100 further has a plurality of lift pins 39. The plurality of lift pins 39 are attached to the end of the substrate lifting unit 4.

[0078] The plurality of lift pins 39 move along the axial direction in conjunction with the substrate lifting unit 4. The plurality of lift pins 39 are pushed by the substrate lifting unit 4 to protrude from the top surface 13 of the lower electrode 15. The plurality of lift pins 39 are pulled by the substrate lifting unit 4 to be stored inside the lower electrode 15. For ease of explanation, the plurality of lift pins 39 are not shown in each of FIGS. 1, 5, 7, and 8.

[0079] The substrate 80 is released from the fixation by the substrate holder 1. In the vacuum processing space 52, the substrate lifting unit 4 lifts the substrate 80 in the direction of arrow A4. Specifically, the substrate lifting unit 4 pushes each of the multiple lift pins 39 in the direction of arrow A4. Each of the multiple lift pins 39 pushes the substrate 80 in the direction of arrow A4. Arrow A4 is the direction from the lower electrode 15 to the upper electrode 25. The lifted substrate 80 is carried out of the dry etching apparatus 100 by a transport unit (not shown). In this manner, the semiconductor substrate 110 is produced.

[0080] (Action and effect) Next, the effects of the dry etching apparatus 100 and the method for manufacturing a semiconductor substrate according to this embodiment will be described.

[0081] When the exhaust port 29 is provided on the side surface of the chamber 2, the flow of the process gas over the substrate 80 is biased in the direction of the exhaust port 29. As a result, the distribution of the etching rate is biased in the direction of the exhaust port 29.

[0082] In the dry etching apparatus 100 according to the present disclosure, the exhaust port 29 intersects with the central axis O of the substrate holder 1. Therefore, the process gas flows radially above the substrate 80. This causes the flow of the process gas above the substrate 80 to approach rotational symmetry. As a result, the distribution of the etching rate on the semiconductor substrate 110 can approach rotational symmetry.

[0083] According to the dry etching apparatus 100 of this embodiment, each of the plurality of vent pipes 3 is positioned rotationally symmetrically about the central axis O. Therefore, compared to a case where each of the plurality of vent pipes 3 is not positioned rotationally symmetrically about the central axis O, the flow of the process gas around the substrate holder 1 approaches rotational symmetry about the central axis O. This allows the flow of the process gas over the substrate 80 to approach rotational symmetry. As a result, the distribution of the etching rate on the semiconductor substrate 110 can be more effectively brought closer to rotational symmetry.

[0084] When the total area of ​​the multiple vent pipes 3 is excessively large in the axial direction, the flow rate of the exhausted process gas becomes excessively small. This makes it difficult to maintain a low-pressure environment in the dry etching apparatus 100 during processing. In the dry etching apparatus 100 according to this embodiment, in a cross section perpendicular to the central axis O and where the cross-sectional area of ​​the multiple vent pipes 3 is greatest, the value obtained by dividing the cross-sectional area of ​​the multiple vent pipes by the area of ​​the exhaust flow path is less than 0.5. This prevents a decrease in the flow rate of the exhausted process gas, thereby maintaining a low-pressure environment during processing.

[0085] According to the dry etching apparatus 100 of this embodiment, each of the multiple pipes 30 is located inside the first ventilation pipe 31. In other words, each of the multiple pipes 30 is not exposed to the processing space 52. Therefore, each of the multiple pipes 30 does not come into contact with the process gas. In other words, each of the multiple pipes 30 does not affect the flow of the process gas. This makes it possible to more effectively approximate the distribution of the etching rate on the semiconductor substrate 110 to rotational symmetry.

[0086] According to the dry etching apparatus 100 of this embodiment, the first electrical wiring 44 is located inside the third ventilation pipe 33. In other words, the first electrical wiring 44 is not exposed to the processing space 52. Therefore, the first electrical wiring 44 does not come into contact with the process gas. In other words, the first electrical wiring 44 does not affect the flow of the process gas. This makes it possible to more effectively approximate the distribution of the etching rate on the semiconductor substrate 110 to rotational symmetry.

[0087] According to the dry etching apparatus 100 of this embodiment, the first pipe 41 supplies the coolant to the substrate holding part 1. This allows the lower electrode 15 of the substrate holding part 1 to be cooled.

[0088] According to the dry etching apparatus 100 of this embodiment, the second pipe 42 supplies a low dew point gas to the internal space 51. This makes it possible to suppress condensation caused by the refrigerant in the internal space 51. This makes it possible to suppress the occurrence of rust on the lower electrode 15 due to condensation.

[0089] According to the dry etching apparatus 100 of this embodiment, the second pipe 42 supplies a low dew point gas to the internal space 51. This makes it possible to suppress condensation caused by the refrigerant in the internal space 51. This makes it possible to suppress the occurrence of rust in the substrate lifting unit 4 due to condensation.

[0090] In the dry etching apparatus 100 according to this embodiment, the second vent pipe 32 exhausts the low dew point gas from the internal space 51 to the outside of the chamber 2. The second vent pipe 32 is different from the first vent pipe 31. This makes it possible to suppress the obstruction of exhaust of the low dew point gas by the multiple pipes 30 located inside the first vent pipe 31. This allows the low dew point gas to be stably exhausted.

[0091] Furthermore, in the dry etching apparatus 100 according to this embodiment, the third vent pipe 33 is different from the first vent pipe 31. The electrical wiring 44 is located inside the third vent pipe 33. The multiple pipes 30 are located inside the first vent pipe 31. Therefore, contact between the first electrical wiring 44 and each of the multiple pipes 30 can be suppressed.

[0092] According to the dry etching apparatus 100 of this embodiment, the diameter D1 of the substrate mounting portion is 90 mm or more. Therefore, etching can be performed on a substrate 80 having a diameter of 90 mm or more. In this way, even when etching a large-diameter substrate 80, the distribution of the etching rate on the semiconductor substrate 110 can be made closer to rotational symmetry.

[0093] The dry etching apparatus 100 according to this embodiment has a substrate lifting unit 4. The substrate lifting unit 4 lifts the substrate 80. This allows the substrate 80 to be efficiently carried out. This improves the productivity of the dry etching apparatus 100.

[0094] In the dry etching apparatus 100 according to this embodiment, the substrate holding unit 1 is spaced apart from the chamber 2. The substrate lifting unit 4 is located in the internal space 51 of the substrate holding unit 1. This allows for both a structure in which the substrate holding unit 1 and the exhaust port 29 are coaxially located and a structure in which the substrate lifting unit 4 is provided. As a result, the etching rate distribution can be made closer to rotational symmetry, and the productivity of the dry etching apparatus 100 can be improved.

[0095] Furthermore, in the dry etching apparatus 100 according to this embodiment, the substrate lifting / lowering unit 4 is located in the internal space 51. The internal space 51 is connected to the atmospheric space. Therefore, the stability of the operation of the substrate lifting / lowering unit 4 can be improved compared to when the substrate lifting / lowering unit 4 is exposed to an environment such as a vacuum.

[0096] When the distance H1 between the upper electrode 25 and the lower electrode 15 is changed by moving the lower electrode 15 up and down, the volume of the internal space 51 increases or decreases. According to the dry etching apparatus 100 of this embodiment, the spacer flange 7 can change the distance H1 between the upper electrode 25 and the lower electrode 15 in the axial direction. Therefore, the distance H1 between the upper electrode 25 and the lower electrode 15 can be changed without increasing or decreasing the volume of the internal space 51.

[0097] In the dry etching apparatus 100 according to this embodiment, the plurality of vent pipes 3 are configured with four vent pipes. However, the number of vent pipes is not limited to four. Specifically, the plurality of vent pipes 3 may be configured with two vent pipes or three vent pipes. For example, when the plurality of vent pipes 3 are configured with two vent pipes, the plurality of pipes 30 and the first electrical wiring 44 are located inside different vent pipes. The low dew-point gas is exhausted from at least one of the two vent pipes.

[0098] Furthermore, the dry etching apparatus 100 according to this embodiment has a plurality of pipes 30. However, the dry etching apparatus 100 does not necessarily have to have a plurality of pipes. Specifically, the dry etching apparatus 100 may have, for example, at least one pipe.

[0099] Furthermore, according to the dry etching apparatus 100 of this embodiment, each of the multiple pipes 30 is located inside the first ventilation pipe 31. However, each of the multiple pipes 30 may be located inside a different ventilation pipe.

[0100] (Example) (Sample preparation) Next, a test using a sample will be described. First, a semiconductor substrate 110 relating to the sample was prepared. The semiconductor substrate 110 relating to the sample was fabricated using the semiconductor substrate fabrication method according to the present embodiment described above. In fabricating the semiconductor substrate 110 relating to the sample, a fluorine-based gas was used as the process gas. The etching time was 45 seconds. The diameter of the semiconductor substrate 110 was 100 mm.

[0101] (Measurement method) The etching rate was measured for the sample. Specifically, a metal film with an opening was formed on the sample surface. When etching was performed, a step was generated between the portion protected by the metal film and the portion not protected by the metal film. The depth of the step was measured, and the absolute value of the step depth was divided by the etching time to calculate the etching rate. A white light interferometer "ContourGT-I" manufactured by BRUKER was used to measure the depth of the step formed on the semiconductor substrate 110.

[0102] Fig. 10 is a schematic plan view showing the measurement positions of the etching rate. As shown in Fig. 10, a semiconductor substrate 110 has a main surface 88. Five concentric circles 84 are assumed, each centered at a center 85 of the main surface 88. Each of the five concentric circles 84 has a common center 85.

[0103] 10 , a plurality of measurement points 93 are located on the main surface 88. Specifically, the plurality of measurement points 93 are located on a first line 81 that passes through the center 85 and is parallel to a first direction 101, on a second line 82 that passes through the center 85 and is parallel to a second direction 102, and on two third lines 83 that pass through the center 85 and bisect the angle formed by the first line 81 and the second line 82. Note that the first direction 101 is not particularly limited, but may be, for example, the <11-20> direction. The second direction 102 is not particularly limited, but may be, for example, the <1-100> direction.

[0104] The diameters of the five concentric circles 84 are 10 mm, 30 mm, 50 mm, 70 mm, and 90 mm, respectively. Measurement points 93 are located at the intersections of each of the five concentric circles 84 with the first line 81, the second line 82, and the two third lines 83. From another perspective, the distance between adjacent measurement points 93 (hereinafter referred to as the third distance H3) among the multiple measurement points 93 located on a line is 10 mm. The etching rate was measured at all of the measurement points 93. As shown in FIG. 10, the number of measurement points 93 was 40.

[0105] (Measurement results) FIG. 11 is a diagram showing the relationship between the etching rate and the distance from the center of the main surface in the example. In FIG. 11, the vertical axis represents the etching rate, and the horizontal axis represents the distance from the center 85 of the main surface 88. In FIG. 11, the etching rates for the first line 81, the second line 82, and the two third lines 83 (see FIG. 10) are plotted in an overlapping manner. In other words, in FIG. 11, the four circles aligned on the lines parallel to the vertical axis represent the etching rates at measurement points 93 that are equally distant from the center 85 for the first line 81, the second line 82, and the two third lines 83.

[0106] In each of the first straight line 81 and the two third straight lines 83, the distance of the measurement point 93 from the center 85, with the center 85 being 0, increases as the distance from the center 85 increases along the first direction 101 and decreases as the distance from the center 85 increases along the direction opposite to the first direction 101. In the second straight line 82, the distance of the measurement point 93 from the center 85, with the center 85 being 0, increases as the distance from the center 85 increases along the second direction 102 and decreases as the distance from the center 85 increases along the direction opposite to the second direction 102.

[0107] 11 , a substantially rotationally symmetrical distribution of etching rates was obtained on the main surface 88 of the semiconductor substrate 110, centered on the center 85. This confirms that the method for manufacturing a semiconductor substrate according to this embodiment makes it possible to obtain a substantially rotationally symmetrical distribution of etching rates on the main surface 88 of the semiconductor substrate 110.

[0108] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the above-described embodiments, and it is intended to include any modifications within the scope of the claims and meanings equivalent to the claims. [Explanation of symbols]

[0109] 1 Board holding part 2 chambers 3 Ventilation pipe 4. Board lifting section 6 Gas Ring 7 Spacer flange 8 Conductance Control Valve 9 Rectifier plate 10 Storage section 11 First outer circumferential surface (outer circumferential surface) 12 First inner surface 13 Top surface 14 Bottom 15 Lower electrode (electrode) 17 1st bottom 18 First cylinder part 21 Second outer peripheral surface 22 Second inner circumferential surface (inner circumferential surface) 25 Upper electrode 27 Second bottom 28 Second tube part 29 Exhaust port 30 tubes 31 First ventilation pipe 32 Second ventilation pipe 33 Third ventilation pipe 34 No. 4 ventilation pipe 35 Gas flow path 36 Air Outlet 37 Exhaust flow path 39 Lift Pin 41 Pipe 1 42 2nd pipe 43 3rd tube 44 First Electrical Wiring (Electrical Wiring) 45 Second electrical wiring 51 Interior Space 52 Processing Space 61 Board mounting section 62 Base 70 Metallic parts 71 Part 1 72 Part 2 73 Insulating materials 74 Refrigerant circulation parts 75 Board gripping member 76 Cover member 80 boards 81 1st straight line 82 Second straight line 83 3rd straight line 84 concentric circles 85 center 88 Main Surface 91 High frequency power supply 92 Microwave power supply 93 measurement points 100 Dry Etching Equipment 101 1st direction 102 Second direction 110 Semiconductor substrate A1, A2, A3, A4 arrows D1 1st diameter (diameter) D2 2nd diameter H1 1st distance H2 2nd distance (distance) H3 3rd distance O center axis θ angle

Claims

1. a chamber provided with an exhaust port; a substrate holder located within the chamber and spaced apart from the chamber; a plurality of vent tubes supported by the chamber; the exhaust port intersects with a central axis of the substrate holder, an internal space is provided in the substrate holding portion, At least one of the plurality of ventilation pipes connects the interior space to the outside of the chamber, the substrate holder is supported by the plurality of ventilation pipes; A dry etching apparatus, wherein the diameter of the exhaust port is larger than the diameter of the substrate holder.

2. 2. The dry etching apparatus according to claim 1, wherein each of said plurality of vent pipes is positioned rotationally symmetrically with respect to said central axis.

3. the chamber includes an inner circumferential surface communicating with each of the plurality of vent pipes; the substrate holding portion includes an outer circumferential surface that is connected to each of the plurality of vent pipes and faces the inner circumferential surface, 3. The dry etching apparatus according to claim 1, wherein, at any position on the inner circumferential surface between adjacent vent pipes among the plurality of vent pipes, the distance between the inner circumferential surface and the outer circumferential surface in a direction perpendicular to the central axis is equal.

4. An exhaust flow path is formed between adjacent ones of the plurality of ventilation pipes, 4. The dry etching apparatus according to claim 1, wherein a value obtained by dividing the cross-sectional area of ​​the plurality of vent pipes by an area of ​​the exhaust flow path in a cross section perpendicular to the central axis and at which the cross-sectional area of ​​the plurality of vent pipes is maximum is less than 0.

5.

5. 5. The dry etching apparatus according to claim 4, wherein the shape of the exhaust flow path is rotationally symmetric with respect to the central axis.

6. further comprising at least one tube connected to the substrate holder; the plurality of ventilation pipes includes a first ventilation pipe; 6. The dry etching apparatus according to claim 1, wherein the at least one pipe is located inside the first vent pipe.

7. the at least one tube includes a first tube; 7. The dry etching apparatus according to claim 6, wherein the first pipe supplies a coolant to the substrate holder.

8. the at least one tube includes a second tube; 8. The dry etching apparatus according to claim 6, wherein the second pipe supplies nitrogen gas or dry air to the internal space.

9. the plurality of ventilation pipes further include a second ventilation pipe that exhausts the nitrogen gas or the dry air from the internal space to an outside of the chamber; 9. The dry etching apparatus of claim 8, wherein the second vent pipe is different from the first vent pipe.

10. further comprising electrical wiring connected to the electrodes of the substrate holding part; the electrical wiring is constituted by a cable or a bus bar, the plurality of vent pipes further include a third vent pipe different from the first vent pipe and a fourth vent pipe different from each of the first vent pipe and the third vent pipe; the electrical wiring is located inside the third ventilation pipe; 10. The dry etching apparatus according to claim 6, wherein a lid is attached to each of the first vent pipe, the third vent pipe, and the fourth vent pipe at an end close to the chamber.

11. the substrate holding portion includes a substrate mounting portion, 11. The dry etching apparatus according to claim 1, wherein the diameter of the substrate mounting portion is 90 mm or more.

12. 12. The dry etching apparatus according to claim 1, further comprising a substrate lifting unit located in the internal space.

13. 13. The dry etching apparatus according to claim 1, wherein the substrate holder is supported only by the plurality of ventilation pipes.

14. A method for manufacturing a semiconductor substrate using the dry etching apparatus according to any one of claims 1 to 13, placing a substrate on the substrate holder; and performing plasma etching on the substrate.

15. The method for manufacturing a semiconductor substrate according to claim 14 , wherein the substrate is made of silicon carbide.

16. The method for manufacturing a semiconductor substrate according to claim 14 or 15, wherein the substrate includes an epitaxial layer.

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