Etching device

Abstract

To provide a technique that can apply a bias potential to a support portion.SOLUTION: An etching device includes a mounting unit 20, a potential application member 30, a lifting / lowering drive unit 40, a plasma generator 50, and a heating unit 80. A portable support unit 21 supporting a substrate W is mounted on the mounting unit 20. The heating unit 80 is located below the mounting unit 20 and includes a light source 81 that emits light for heating and heats the substrate W. The potential application member 30 is provided above the mounting unit 20 and is applied with a predetermined bias potential. The lifting / lowering drive unit 40 lifts and lowers the mounting unit 20 between an upper position where the potential application member 30 comes into contact with the substrate W or the support unit 21 and a lower position where the potential application member 30 is separated from the substrate W and the support unit 21. The plasma generator 50 generates plasma and supplies the plasma to the upper surface of the substrate W on the support unit 21 mounted on the mounting unit 20, thereby etching the upper surface of the substrate W with the plasma.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an etching apparatus. [Background technology]

[0002] Conventionally, devices for etching group III nitride semiconductors have been proposed (for example, Patent Documents 1 and 2). In Patent Documents 1 and 2, the etching device heats a substrate, turns a chlorine-based gas containing chlorine into plasma, and supplies the plasma to the substrate. Ions and radicals in the plasma act on the substrate, etching the group III nitride semiconductor on the substrate.

[0003] Furthermore, in conventional plasma devices, a substrate is placed on a placement section on which a base material to which a bias potential is applied is disposed together with a heater-embedded electrostatic chuck (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-80349 A [Patent Document 2] JP 2018-152415 A [Patent Document 3] JP 2009-170509 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the case of a mounting section that includes a heater-embedded electrostatic chuck and a substrate to which a bias potential is applied, a design that suppresses interference with the electric field is required, resulting in a complex mechanism.

[0006] On the other hand, the support part supporting the substrate may be transported into the chamber of the etching device. In the chamber, the support part is placed on the placement part. When a bias potential is applied to the placement part in the chamber, an electric field due to the bias potential can be generated in the space above the substrate. This allows ions of the plasma above the substrate to move toward the substrate. However, due to heating by an electric resistance heater, thermal expansion occurs in the members of the placement part, which may cause warping of the members of the placement part. In addition, in processing with corrosive gas at high temperatures by heating by an electric resistance heater, deformation of the members of the placement part may occur due to discharge corrosion. When warping or deformation of the members of the placement part occurs, the formation of an electric field in the space above the substrate becomes unstable.

[0007] Therefore, an object of the present disclosure is to provide a technique capable of forming a stable electric field in the space above a substrate. [Means for solving the problem]

[0008] A first aspect is an etching apparatus comprising: a mounting section on which a portable support section supporting a substrate is placed; a heating section located below the mounting section and including a light source that emits heating light to heat the substrate; a potential application member located above the mounting section and to which a predetermined bias potential is applied; a lifting drive section that raises and lowers the mounting section between an upper position where the potential application member contacts the substrate or the support section and a lower position where the potential application member is spaced apart from the substrate and the support section; and a plasma generator that generates plasma, supplies the plasma to an upper surface of the substrate on the support section placed on the mounting section, and etches the upper surface of the substrate with the plasma.

[0009] A second aspect is the etching apparatus according to the first aspect, wherein the placement portion is translucent to the light.

[0010] A third aspect is the etching apparatus according to the second aspect, wherein, at the upper position, the potential application member contacts the upper surface of the substrate.

[0011] A fourth aspect is an etching apparatus according to any one of the first to third aspects, comprising a chamber, the chamber including a cylindrical portion that houses the potential application member and the placement portion, and an entry portion that is connected to a portion of a side wall of the cylindrical portion that is lower than the potential application member and through which the substrate and the support portion pass.

[0012] A fifth aspect is the etching apparatus according to any one of the first to fourth aspects, wherein the potential application member includes conductive carbon and a silicon carbide film formed on a surface of the conductive carbon.

[0013] A sixth aspect is the etching apparatus according to any one of the first to fifth aspects, wherein the potential application member includes a circular member having a circular shape in a plan view. Effect of the Invention

[0014] According to the first aspect, a stable electric field can be formed in the space above the substrate.

[0015] According to the second aspect, the light from the light source is transmitted through the placement part and enters the support part. This makes it possible to heat the support part that is closer to the substrate. This improves the heating efficiency for the substrate.

[0016] According to the third aspect, the potential application member can press the substrate against the support portion, thereby improving the adhesion between the lower surface of the substrate and the upper surface of the support portion, thereby allowing the heat of the support portion to be transferred to the substrate more effectively.

[0017] According to the fourth aspect, the portion of the inner circumferential surface of the cylindrical portion above the substrate can be formed into a cylindrical shape. This makes it possible to make the flow of plasma uniform in the space above the substrate. This allows the plasma to act more uniformly on the upper surface of the substrate.

[0018] According to the fifth aspect, the reliability of the potential application member can be improved.

[0019] According to the sixth aspect, the flow of plasma in the space above the substrate can be made more uniform, so that the plasma can act more uniformly on the upper surface of the substrate. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an etching apparatus. [Diagram 2] FIG. 2 is a top view illustrating an example of a configuration of a chamber. [Diagram 3] FIG. 2 is a perspective view illustrating an example of a configuration of a circular ring member. [Figure 4] FIG. 1 is a diagram illustrating an example of the configuration of an etching apparatus. [Diagram 5] FIG. 1 is a diagram illustrating an example of the configuration of an etching apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the drawings, the dimensions and numbers of each part are exaggerated or simplified as necessary for the purpose of easy understanding. Parts having similar configurations and functions are given the same reference numerals, and duplicated explanations will be omitted in the following description.

[0022] In the following description, the same components are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions thereof may be omitted to avoid duplication.

[0023] Furthermore, in the description below, even if ordinal numbers such as "first" or "second" are used, these terms are used for convenience to facilitate understanding of the contents of the embodiments, and are not limited to the ordering that may result from these ordinal numbers.

[0024] When an expression indicating a relative or absolute positional relationship (e.g., "in one direction," "along one direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.) is used, the expression not only strictly indicates the positional relationship, but also indicates a state in which the relative positional relationship is displaced with respect to angle or distance within a range in which a tolerance or similar function is obtained, unless otherwise specified. When an expression indicating an equal state (e.g., "same," "equal," "homogeneous," etc.) is used, the expression not only strictly indicates a quantitatively equal state, but also indicates a state in which a difference exists within a range in which a tolerance or similar function is obtained, unless otherwise specified. When an expression indicating a shape (e.g., "square shape" or "cylindrical shape," etc.) is used, the expression not only strictly indicates the shape geometrically, but also indicates a shape having, for example, unevenness or chamfering within a range in which a similar effect is obtained, unless otherwise specified. When an expression "comprises," "has," "includes," "includes," or "has" a component is used, the expression is not an exclusive expression that excludes the presence of other components. When the phrase "at least one of A, B, and C" is used, the phrase includes A only, B only, C only, any two of A, B, and C, and all of A, B, and C.

[0025] <Etching equipment> FIG. 1 is a diagram illustrating an example of the configuration of an etching apparatus 1. The etching apparatus 1 performs etching on a substrate W. A group III nitride semiconductor film, which is an etching target, is formed on the upper surface of the substrate W. For example, a gallium nitride (GaN) semiconductor is applied as the group III nitride semiconductor. The gallium nitride semiconductor can be used in devices such as power devices, high frequency devices, and optical devices. The gallium nitride semiconductor film can be formed on, for example, a silicon (Si) substrate or a silicon carbide (SiC) substrate. On the upper surface of the substrate W, a resist having a predetermined pattern may be formed on the group III nitride semiconductor film. The substrate W has, for example, a circular shape in a plan view.

[0026] The etching apparatus 1 includes a mounting section 20, a potential application member 30, a lifting and lowering drive section 40, a plasma generator 50, a heating section 80, and a control section 90.

[0027] As shown in FIG. 1, the etching apparatus 1 may be provided with a chamber 10. The chamber 10 is a housing that forms a processing chamber in which etching is performed on the substrate W. The internal space surrounded by the inner peripheral surface of the chamber 10 corresponds to the processing chamber. FIG. 2 is a top view that shows an example of the configuration of the chamber 10. In the example of FIGS. 1 and 2, the chamber 10 includes a cylindrical portion 11 and a loading portion 12. The cylindrical portion 11 has a cylindrical shape with both ends closed. Specifically, the cylindrical portion 11 includes a ceiling portion that is circular in plan view, a floor portion that is circular in plan view, and a cylindrical side wall portion that connects the periphery of the ceiling portion and the periphery of the floor portion. The loading portion 12 is connected to the side wall portion of the cylindrical portion 11 and has a substantially rectangular box shape. The internal space of the loading portion 12 is connected to the internal space of the cylindrical portion 11. Inside the loading portion 12, the substrate W and the support portion 21 are transported by a transport robot as described later. The loading section 12 is provided with a shutter (not shown) that is driven to open and close. The loading section 12 may be a gate valve. The processing chamber mainly corresponds to the internal space of the cylindrical section 11. As shown in FIG. 1, the chamber 10 is conductive and can be grounded.

[0028] In the example of FIG. 1, a pressure reducing unit 70 is connected to the chamber 10. The pressure reducing unit 70 is a device that reduces the pressure in the chamber 10. The pressure reducing unit 70 includes an exhaust pipe 71 and a suction driving unit 72. The upstream end of the exhaust pipe 71 is connected to the chamber 10. For example, the upstream end of the exhaust pipe 71 is connected to the side wall of the chamber 10. Note that the upstream ends of the multiple exhaust pipes 71 may be connected to the side wall of the chamber 10 at positions that are equally spaced in the circumferential direction. The suction driving unit 72 is provided in the exhaust pipe 71. The suction driving unit 72 includes, for example, a vacuum pump. The suction driving unit 72 sucks gas in the chamber 10 through the exhaust pipe 71. This reduces the pressure in the chamber 10. The suction driving unit 72 is controlled by a control unit 90. A pressure sensor that measures the pressure in the chamber 10 may be provided. The control unit 90 may control the suction driving unit 72 so that the pressure measured by the pressure sensor is within a predetermined pressure range.

[0029] The placement unit 20 is provided in the chamber 10. As described below, the support unit 21 is placed on the upper surface of the placement unit 20. The upper surface of the placement unit 20 may be a horizontal flat surface. The placement unit 20 has, for example, a circular shape in a plan view.

[0030] The support portion 21 has, for example, a plate-like shape. The support portion 21 is placed on the placement portion 20 in a horizontal position with its thickness direction aligned along the vertical direction. The support portion 21 supports the substrate W in a horizontal position with the thickness direction of the substrate W aligned along the vertical direction. The upper surface of the support portion 21 may be a horizontal flat surface. The upper surface of the support portion 21 is in contact with the lower surface of the substrate W. The support portion 21 may be wider than the substrate W in a planar view. That is, the periphery 21a of the support portion 21 may be located outside the periphery of the substrate W in a planar view. The support portion 21 has, for example, a circular shape in a planar view. In this case, the diameter of the support portion 21 may be larger than the diameter of the substrate W. The support portion 21 may be provided with a holding mechanism for holding the substrate W.

[0031] The support portion 21 has electrical conductivity. The support portion 21 may be formed of, for example, a metal material, or may be formed of conductive carbon. A silicon carbide (SiC) film may be formed on the surface of the support portion 21.

[0032] The support part 21 is transported together with the substrate W. That is, a transport robot outside the etching apparatus 1 transports the support part 21 supporting the substrate W. The transport robot transports the unprocessed substrate W and the support part 21 together into the chamber 10. Specifically, the transport robot transports the substrate W and the support part 21 into the cylindrical part 11 through the inside of the carry-in part 12, and places the support part 21 on the placement part 20. The etching apparatus 1 performs etching on the substrate W as described later. The transport robot transports the processed substrate W and the support part 21 together out of the chamber 10. Specifically, the transport robot takes out the substrate W and the support part 21 from the placement part 20 and carries them out through the inside of the carry-in part 12. Such a support part 21 can also be said to be a portable support part. The support part 21 can also be called a susceptor. On the other hand, the placement part 20 can also be said to be a stationary placement part installed in the etching apparatus 1.

[0033] 1, the mounting part 20 is an upper part of a storage member 82 that houses the heating part 80. Specifically, the mounting part 20 is a plate-shaped portion at the upper part of the storage member 82. The storage member 82 includes the plate-shaped mounting part 20 and a cylindrical side wall part 821 that extends vertically downward from the periphery of the mounting part 20. The internal space of the storage member 82 may be isolated from the processing chamber in the chamber 10. The side wall part 821 may be connected to the floor surface of the chamber 10 via a bellows (not shown), for example.

[0034] The heating unit 80 includes a light source 81. The light source 81 is provided inside the storage member 82. The light source 81 is provided at a position facing the placement unit 20 in the vertical direction, and emits light for heating. The light for heating may be, for example, infrared light. The light source 81 may be, for example, a halogen lamp. As shown in FIG. 1, a plurality of light sources 81 may be provided. The plurality of light sources 81 may be lined up in the horizontal direction inside the storage member 82.

[0035] The mounting portion 20 may be translucent for the light emitted by the light source 81. The transmittance of the mounting portion 20 for the light may be, for example, 60% or more, 80% or more, or 95% or more. The mounting portion 20 may be made of, for example, quartz glass. The mounting portion 20 may also be insulating. If the mounting portion 20 contains a conductive material, the transmittance of the mounting portion 20 decreases, but by employing an insulating mounting portion 20, the transmittance of the mounting portion 20 can be easily increased.

[0036] The light emitted by the light source 81 passes through the placement unit 20 and is absorbed by at least one of the support unit 21 and the substrate W. This heats up the substrate W. As a specific example, the absorptivity of the support unit 21 for the light is higher than the absorptivity of the placement unit 20 for the light. In this case, at least a part of the light emitted by the light source 81 is absorbed by the support unit 21. This heats up the support unit 21, and the heat of the support unit 21 is transferred to the substrate W, increasing the temperature of the substrate W. This increase in the temperature of the substrate W can improve the etching rate of the III nitride semiconductor film of the substrate W. In other words, the light source 81 emits light so that the temperature of the substrate W is within a predetermined temperature range suitable for etching. This can shorten the time during which the substrate W is exposed to the plasma described below, and can reduce damage to the substrate W caused by the plasma described below.

[0037] In the example of FIG. 1, a reflecting section 83 is provided inside the storage member 82. The reflecting section 83 is provided on the opposite side of the light source 81 from the placement section 20 (here, vertically downward). The reflecting section 83 has reflectivity for the light emitted by the light source 81. The reflecting section 83 may be formed of a metal such as aluminum. The reflectance of the reflecting section 83 for the light may be, for example, 60% or more, 80% or more, or 95% or more. The light from the light source 81 toward the reflecting section 83 is reflected by the reflecting section 83 and travels toward the placement section 20. This can increase the amount of light traveling toward the placement section 20, and can improve the heating efficiency.

[0038] The potential application member 30 is a member for applying a bias potential to the support 21 or the substrate W. The potential application member 30 is conductive. The potential application member 30 may be made of, for example, conductive carbon, or a silicon carbide film may be formed on the surface of the conductive carbon.

[0039] In the example of FIG. 1, the potential application member 30 includes a conductive ring member 31 and a conductive support column 32. FIG. 3 is a perspective view that shows an example of the configuration of the ring member 31. The ring member 31 has a plate-like shape and has a ring shape in a plan view. In the example of FIG. 1, the ring member 31 is provided vertically above the placement unit 20. An inner peripheral edge 31a of the ring member 31 is located inside the peripheral edge 21a of the support unit 21 in a plan view, and an outer peripheral edge 31b of the ring member 31 is located outside the peripheral edge 21a of the support unit 21 in a plan view. In other words, the inner diameter (diameter) of the ring member 31 is smaller than the diameter of the support unit 21, and the outer diameter (diameter) of the ring member 31 is larger than the diameter of the support unit 21. In the example of FIG. 1, the inner peripheral edge 31a of the ring member 31 is located outside the peripheral edge of the substrate W. In other words, the inner diameter (diameter) of the ring member 31 is larger than the diameter of the substrate W.

[0040] As shown in Figures 1 and 3, the circular member 31 may be inclined downward toward the inside. The circular member 31 may be rotationally symmetrical with respect to an imaginary axis that passes through the center of the substrate W and is aligned in the vertical direction. In the example of Figures 1 and 3, the circular member 31 has a plate-like shape that follows the side surface of a truncated cone. In this shape, the diameter of the circular member 31 in a horizontal cross section becomes wider toward the vertically upward direction. The upper surface of the circular member 31 may be a flat surface.

[0041] The support pillar 32 has a rod-like shape extending along the vertical direction, with an upper end of the support pillar 32 connected to the circular ring member 31 and a lower end of the support pillar 32 connected to, for example, the floor surface of the chamber 10. The upper end of the support pillar 32 is connected to, for example, the lower surface of the circular ring member 31. The support pillar 32 is located outside the storage member 82 and supports the circular ring member 31. The support pillar 32 is electrically connected to a power supply unit 60, which will be described later.

[0042] The annular member 31 may be supported not only by the support columns 32 but also by the support columns 33. More specifically, one or more support columns 32 and one or more support columns 33 may be provided. The support columns 33 have a rod-like shape extending along the vertical direction, and are provided at a position different from the support columns 32 in a plan view. For example, the support columns 32 and 33 are provided at intervals so as to surround the support unit 21 and the storage member 82. The upper end of the support column 33 is connected to the annular member 31, and the lower end of the support column 33 is connected to the floor surface of the chamber 10. The support columns 33 may be insulating. Each of the support columns 32 and 33 is provided at a position that avoids the transport path of the substrate W and the support unit 21.

[0043] A bias power supply unit 60 is electrically connected to the potential application member 30. The power supply unit 60 includes, for example, a matching circuit 61 and a high-frequency power supply 62. The matching circuit 61 is connected in series to the potential application member 30 and the high-frequency power supply 62. The matching circuit 61 is a circuit that matches a power supply impedance and a load impedance. One end of the high-frequency power supply 62 is electrically connected to the potential application member 30 (for example, the support column 32) through the matching circuit 61, and the other end of the high-frequency power supply 62 is electrically grounded. The high-frequency power supply 62 applies a high-frequency voltage (bias potential) between the potential application member 30 and the ground through the matching circuit 61. The frequency of the bias potential is, for example, 2 MHz.

[0044] The lifting drive unit 40 lifts and lowers the mounting unit 20 between an upper position and a lower position. Fig. 4 is a diagram that shows a schematic example of the configuration of the etching apparatus 1. Fig. 1 shows the etching apparatus 1 in a state where the mounting unit 20 is located in the lower position, and Fig. 4 shows the etching apparatus 1 in a state where the mounting unit 20 is located in the upper position.

[0045] The upper position is a position where at least one of the support part 21 and the substrate W (support part 21 in FIG. 4) is in contact with the potential application member 30. Therefore, the potential application member 30 is electrically connected to the support part 21. With the potential application member 30 in contact with the support part 21, a bias potential can be applied to the support part 21. As shown in FIG. 1, the lower position is a position vertically lower than the upper position, and is a position where both the support part 21 and the substrate W are separated from the potential application member 30. With the mounting part 20 in the lower position, the substrate W and the support part 21 are taken out of the mounting part 20 or transferred to the mounting part 20 by a transfer robot outside the chamber 10.

[0046] The lift drive unit 40 includes, for example, a drive source such as a motor, and a power conversion unit such as a ball screw mechanism, etc. Alternatively, the lift drive unit 40 may include an air cylinder.

[0047] 1, the upper part of the loading section 12 is located vertically below the circular member 31. The internal space of the loading section 12 is horizontally connected to the space between the circular member 31 and the mounting section 20 located at the lower position. The transport robot moves the substrate W and the support section 21 horizontally through the internal space of the loading section 12, and moves the substrate W and the support section 21 to directly above the mounting section 20. The transport robot then places the support section 21 on the mounting section 20.

[0048] When the lifting and lowering drive unit 40 moves the substrate W, the support unit 21 and the mounting unit 20 together to the upper position, the inner periphery of the potential application member 30 (e.g., the lower end of the inner periphery 31a) comes into contact with the upper surface of the support unit 21. In this state, the power supply unit 60 applies a bias potential to the potential application member 30, so that the bias potential can be applied to the support unit 21.

[0049] The plasma generator 50 is provided vertically above the substrate W on the support 21 placed on the placement unit 20. The plasma generator 50 is provided at a position facing the substrate W in the vertical direction. In the example of FIG. 1 and FIG. 4, the plasma generator 50 is provided on the ceiling of the chamber 10. The type of the plasma generator 50 may be, for example, any of a capacitively coupled plasma type, an inductively coupled plasma type, a microwave plasma type, an electron cyclotron resonance plasma (ECR) type, a helicon wave excited plasma (HWP) type, and a microwave excited surface wave plasma (SWP) type. In the example of FIG. 1 and FIG. 4, the type of the plasma generator 50 is an inductively coupled plasma type, and the plasma generator 50 includes an inductively coupled antenna 51 and a power supply unit 52 for plasma.

[0050] The inductive coupling antenna 51 is formed of a conductive member. For example, the inductive coupling antenna 51 has a U-shaped rod shape. The inductive coupling antenna 51 is provided on the ceiling of the chamber 10 with both ends of the U-shape positioned vertically upward. The inductive coupling antenna 51 may be embedded in the ceiling of the chamber 10. In the example of FIG. 1 and FIG. 4, a plurality of inductive coupling antennas 51 are provided. A power supply unit 52 is electrically connected to the inductive coupling antenna 51. The power supply unit 52 applies a voltage for plasma (e.g., a high-frequency voltage) to both ends of the inductive coupling antenna 51 to generate an electric field for plasma around the inductive coupling antenna 51. For example, the power supply unit 52 includes a matching circuit 521 and a high-frequency power supply 522. The matching circuit 521 is connected in series to the high-frequency power supply 522 and the inductive coupling antenna 51. The matching circuit 521 is a circuit that matches a power supply impedance and a load impedance. One end of the high frequency power supply 522 is electrically connected to one end of the inductive coupling antenna 51 through a matching circuit 521, and the other end of the high frequency power supply 522 is electrically connected to the other end of the inductive coupling antenna 51 and is grounded. The high frequency power supply 522 applies a high frequency voltage to the inductive coupling antenna 51 through the matching circuit 521. The frequency of the high frequency voltage is, for example, 13.56 MHz.

[0051] In the examples of FIG. 1 and FIG. 4, the gas flow path 53a is formed so as to be surrounded by a plurality of inductive coupling antennas 51. The gas flow path 53a is formed by, for example, a gas pipe 53. The internal flow path of the gas pipe 53 corresponds to the gas flow path 53a. The gas pipe 53 extends along the vertical direction, and the inductive coupling antenna 51 is provided around the gas pipe 53. The lower end of the gas pipe 53 opens in the chamber 10. That is, the lower end of the gas pipe 53 corresponds to the outlet of the gas flow path 53a. The upstream end of the gas pipe 53 is connected to a gas supply source 54. The gas supply source 54 includes a reservoir for storing gas, and a valve. The gas supply source 54 supplies, for example, a chlorine-based gas containing a chlorine (Cl) element to the upstream end of the gas pipe 53. The chlorine-based gas may be, for example, chlorine (Cl2) gas, or a mixed gas of chlorine gas and boron chloride (BCl3) gas. The gas supply source may supply a mixed gas containing at least one of hydrogen gas, nitrogen gas, and a rare gas to the gas pipe 53 in addition to the chlorine-based gas.

[0052] The electric field generated by the inductively coupled antenna 51 acts on the gas in the gas pipe 53, converting the gas into plasma. This generates, for example, chlorine ions and chlorine radicals. These ions and radicals flow into the chamber 10 from the outlet of the gas pipe 53 and flow toward the substrate W. The ions and radicals act on the upper surface of the substrate W, etching the Group III nitride semiconductor film on the upper surface of the substrate W.

[0053] The control unit 90 comprehensively controls the etching apparatus 1. Specifically, the control unit 90 controls the shutter of the chamber 10, the lifting drive unit 40, the plasma generator 50, the power supply unit 60, and the pressure reducing unit 70. The control unit 90 is an electronic circuit, and has, for example, a data processing unit and a storage unit. The data processing unit and the storage unit are connected to each other, for example, via a bus. The data processing unit may be, for example, an arithmetic processing device such as a CPU (Central Processor Unit). The storage unit may have a non-transient storage unit (for example, a ROM (Read Only Memory)) and a temporary storage unit (for example, a RAM (Random Access Memory)). The non-transient storage unit may store, for example, a program that specifies the processing to be executed by the control unit 90. The data processing unit executes this program, so that the control unit 90 can execute the processing specified in the program. Of course, a part or all of the processing executed by the control unit 90 may be executed by hardware such as a dedicated logic circuit.

[0054] <An example of the operation of an etching device> Next, a description will be given of an example of the operation of the etching apparatus 1. The operation of the etching apparatus 1 is realized under the control of the control unit 90.

[0055] First, the lifting drive unit 40 stops the placement unit 20 at the lower position, and the transport robot carries the substrate W and the support unit 21 into the chamber 10. Specifically, the support unit 21 supporting the substrate W is moved in the internal space of the loading unit 12 by the transport robot and placed on the placement unit 20. Next, the control unit 90 closes the shutter of the loading unit 12 and causes the pressure reducing unit 70 to reduce the pressure in the chamber 10 to within a predetermined pressure range. In addition, the control unit 90 causes the lifting drive unit 40 to raise the placement unit 20 from the lower position to the upper position. As a result, the potential application member 30 comes into contact with the support unit 21. Then, the control unit 90 causes the power supply unit 60 to apply a bias potential to the potential application member 30 and the support unit 21. In addition, the control unit 90 causes the light source 81 to emit light for heating. As a result, the substrate W is heated.

[0056] Next, the control unit 90 causes the plasma generator 50 to generate plasma. Specifically, the gas supply source 54 supplies a gas containing a chlorine-based gas into the chamber 10 through the gas pipe 53, and the power supply unit 52 supplies high-frequency power to the inductively coupled antenna 51. As a result, an electric field generated around the inductively coupled antenna 51 acts on the gas in the gas pipe 53, and the gas turns into plasma.

[0057] The ions and radicals generated by the plasma flow out from the outlet of the gas pipe 53 into the chamber 10. The ions move toward the support 21 in response to the electric field caused by the bias potential of the support 21. As a result, many ions reach the upper surface of the substrate W. On the other hand, the force of the electric field does not act on the radicals, and therefore the directionality of the radical movement is not as high as that of the ions, but the radicals can reach the upper surface of the substrate W, for example, by following the air flow. The ions and radicals that reach the upper surface of the substrate W act on the Group III nitride semiconductor film, etching the Group III nitride semiconductor film.

[0058] In the above example, since the substrate W is heated by the light source 81, the etching rate by ions and radicals can be improved. Therefore, the time required for etching can be shortened. In other words, since the time during which the substrate W is exposed to the plasma is shortened, damage to the substrate W caused by the plasma can be reduced.

[0059] When the Group III nitride semiconductor film of the substrate W has been sufficiently etched (for example, when a predetermined etching time has elapsed), the control unit 90 ends the etching. Specifically, the control unit 90 stops the operation of the power supply unit 60 and the plasma generator 50, and causes the lifting drive unit 40 to lower the mounting unit 20 to the lower position. This separates the support unit 21 from the potential application member 30, making it possible for the transfer robot to take it out. The control unit 90 also stops the operation of the pressure reduction unit 70. Then, the transfer robot carries the support unit 21 supporting the processed substrate W out of the chamber 10.

[0060] As described above, the etching apparatus 1 can etch the group III nitride semiconductor film of the substrate W. Moreover, in the above example, the lifting driver 40 raises the mounting part 20 to the upper position, thereby bringing the potential application member 30 into contact with the portable support part 21 and applying a bias potential to the portable support part 21. This allows the bias potential to be applied to the support part 21 closer to the substrate W. That is, compared to a comparative structure in which a bias potential is applied to the conductive mounting part 20, the potential application member 30 can directly apply a bias voltage to the support part 21 closer to the substrate W. Therefore, in the space above the substrate W, an electric field that directs ions toward the substrate W can be more effectively generated. This allows the ions in the plasma to be effectively moved to the upper surface of the substrate W.

[0061] In the above example, the stationary mounting part 20 in the chamber 10 is translucent to the light from the light source 81. Since the mounting part 20 is insulating, the transmittance of the mounting part 20 to the light can be increased. This allows a larger amount of light from the light source 81 to be incident on the support part 21, thereby improving the heating efficiency of the support part 21. In this way, the light source 81 can heat the support part 21 that is closer to the substrate W.

[0062] As a comparative example, a structure in which light is absorbed by the placement part 20 will be considered. In this structure, heat is generated in the placement part 20, and the heat is transferred to the substrate W via the support part 21. In this structure, since heat is transferred to the substrate W via the support part 21, the heating efficiency of the substrate W is relatively low. In addition, since the placement part 20 itself becomes hot, when the substrate W and the support part 21 are placed on the high-temperature placement part 20, the support part 21 is likely to be thermally deformed. In contrast, in this embodiment, light is transmitted through the placement part 20 and absorbed by the support part 21. Therefore, the heat generated in the support part 21 is directly transferred to the substrate W. Therefore, the heating efficiency of the substrate W can be increased. Moreover, the temperature rise of the placement part 20 can be suppressed, and the thermal deformation of the support part 21 can also be suppressed.

[0063] As described above, according to the etching apparatus 1, it is possible to improve the heating efficiency of the supporting portion 21 and to apply a bias potential to the supporting portion 21 at the same time.

[0064] In the above example, the substrate W is heated by the light source 81. Therefore, compared to a structure using an electric resistance heater, the occurrence of unnecessary discharge can be suppressed. Here, as a comparative example, a structure in which the mounting part 20 is an electric resistance heater is considered. In this structure, for example, an unnecessary discharge may occur due to an electric field between the support part 21 to which a bias potential is applied and the heating wire in the mounting part 20. If such a discharge occurs, discharge corrosion may occur in the support part 21 or the mounting part 20. In contrast, in the above example, the substrate W is heated by the light source 81, so that the occurrence of such discharge corrosion can be suppressed or prevented. Furthermore, deformation of the support part 21 and the mounting part 20 due to discharge corrosion can be suppressed or prevented, and a stable electric field can be formed in the space above the substrate W.

[0065] Furthermore, in this embodiment, there is no need to provide a conductive member for applying a bias potential and a built-in heater of an electric resistance type inside the mounting section 20, and the configuration of the mounting section 20 can be simplified.

[0066] Also, in the above example, the loading section 12 is located vertically below the annular member 31 of the potential application member 30. Therefore, the inner circumferential surface of the sidewall of the chamber 10 (cylindrical section 11) that is vertically above the potential application member 30 can be made cylindrical. This makes it possible to make the flows of gas and plasma flowing in the space vertically above the substrate W more uniform. This in turn makes it possible to make the ions and radicals act more uniformly on the upper surface of the substrate W. Therefore, the etching apparatus 1 can etch the upper surface of the substrate W more uniformly.

[0067] In the above example, the annular member 31 of the potential application member 30 has an annular shape. Specifically, the upper surface of the annular member 31 has a shape that follows the side surface of a truncated cone. This makes it possible to make the gas flow uniform around the substrate W. This allows the etching apparatus 1 to etch the upper surface of the substrate W more uniformly.

[0068] In the above example, the potential application member 30 includes conductive carbon and a silicon carbide film formed on the surface of the conductive carbon. With this, even if plasma containing, for example, chlorine ions acts on the potential application member 30, the potential application member 30 is hardly corroded. In other words, the reliability of the potential application member 30 can be improved.

[0069] <Another example> 5 is a diagram illustrating another example of the configuration of the etching apparatus 1. In the example of FIG. 5, the lifting drive unit 40 stops the mounting unit 20 at the upper position, and in this state, the potential application member 30 contacts the peripheral portion of the upper surface of the substrate W. That is, in a plan view, the inner peripheral edge 31a of the circular member 31 of the potential application member 30 is located inside the peripheral edge of the substrate W. In other words, the inner diameter (diameter) of the circular member 31 is smaller than the diameter of the substrate W. It is preferable that the potential application member 30 contacts the peripheral portion of the upper surface of the substrate W where no devices are formed.

[0070] According to this structure, the substrate W is sandwiched between the annular member 31 of the potential application member 30 and the support part 21. The potential application member 30 presses the peripheral portion of the substrate W towards the support part 21, so that the lower surface of the substrate W can be brought into closer contact with the upper surface of the support part 21. This allows the heat of the support part 21 to be transferred to the substrate W more efficiently. In other words, the heating efficiency for the substrate W can be improved. Also, there is no need to provide a support chuck that supports the peripheral portion of the substrate W by contacting it.

[0071] As described above, the etching apparatus 1 has been described in detail, but the above description is merely an example in all respects, and this disclosure is not limited thereto. In addition, the above-mentioned various modified examples can be combined and applied as long as they are not mutually inconsistent. It is understood that many modified examples not exemplified can be envisioned without departing from the scope of this disclosure. [Explanation of symbols]

[0072] 1 Etching equipment 10. Chamber 11 Cylindrical part 12 Loading area 20 Placement section 21 Support part 30 Electric potential application member 31 Circular member 40 Lifting drive unit 50 Plasma Generator 81 Light source W substrate

Claims

1. a placement section on which a portable support section supporting a substrate is placed; a heating unit located below the placement unit and including a light source that emits light for heating to heat the substrate; a potential application member provided above the mounting portion and to which a predetermined bias potential is applied; a lifting drive unit that lifts and lowers the placement unit between an upper position where the potential application member contacts the substrate or the support unit and a lower position where the potential application member is separated from the substrate and the support unit; a plasma generator that generates plasma and supplies the plasma to an upper surface of the substrate on the support part placed on the placement part, thereby etching the upper surface of the substrate with the plasma; An etching apparatus comprising:

2. 2. The etching apparatus according to claim 1, The mounting portion is translucent to the light.

3. 3. The etching apparatus according to claim 2, In the upper position, the potential application member contacts the upper surface of the substrate.

4. 4. The etching apparatus according to claim 1, A chamber is provided, The chamber comprises: a cylindrical portion that houses the potential application member and the placement portion; a carry-in section connected to a portion of the side wall of the cylindrical section that is lower than the potential application member, through which the substrate and the support section pass; An etching apparatus comprising:

5. 4. The etching apparatus according to claim 1, The etching apparatus, wherein the potential application member includes conductive carbon and a silicon carbide film formed on a surface of the conductive carbon.

6. 4. The etching apparatus according to claim 1, The etching apparatus, wherein the potential application member includes a circular member having a circular shape in a plan view.

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