Plasma treatment equipment

Abstract

The present invention relates to a plasma processing device capable of suppressing abnormal discharge and finely adjusting the distribution of plasma density. The plasma processing device (10) comprises a gas injection unit (41) and an antenna (54). The gas injection unit supplies processing gas into a chamber (11) from the upper part of the chamber (11). The antenna comprises an inner coil (542) and an outer coil (541). The inner coil is arranged around the gas injection unit. The outer coil is arranged around the gas injection unit and the inner coil. In addition, both ends of the circuit constituting the outer coil are open, and power is supplied from a high-frequency power supply (61) to the midpoint of the circuit or near the midpoint, and the outer coil is grounded near the midpoint to resonate at 1 / 2 wavelength of the high-frequency power supplied from the high-frequency power supply. In addition, with respect to the inner coil, both ends of the circuit constituting the inner coil are connected to each other via a capacitor, and the inner coil and the outer coil are inductively coupled.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application date of September 28, 2018, application number 201811138919.1, and invention name “Plasma Processing Device”. Technical Field

[0002] Various aspects and embodiments of the present invention are directed to a plasma processing apparatus. Background Art

[0003] As a processing device for performing a semiconductor manufacturing process, there is known a plasma processing device that converts a processing gas into plasma to perform etching, film forming, and the like. For example, in a single-chip plasma processing device, it is sought to be able to appropriately adjust the density distribution of the plasma in the surface direction of the substrate according to the type of processing. Specifically, there are cases based on the structure in the processing container, cases corresponding to the deviation of the processing in the substrate surface in post-processing, and the like. Therefore, it is not limited to the processing that makes the density distribution of the plasma in the entire surface of the substrate uniform, and sometimes it is intentionally made to have a difference in the density distribution of the plasma between the central part and the peripheral part of the substrate.

[0004] As a method for generating plasma in a plasma processing device, there is a method of supplying high-frequency power to an antenna to generate an induced electric field in a processing container to excite a processing gas (for example, refer to the following patent document 1). This method describes the following structure: as an antenna that outputs high frequency, a coil-shaped inner antenna and a coil-shaped outer antenna concentric with the inner antenna are provided, and each antenna resonates at a frequency of 1 / 2 wavelength of the high frequency. According to this plasma processing device, the high-frequency power supplied to each antenna is independently controlled, thereby being able to finely adjust the in-plane distribution of the plasma density.

[0005] In addition, there is known a technique in which a processing gas is supplied into a chamber from the center of a dielectric window provided with an antenna in an ICP (Inductively Coupled Plasma) type plasma processing apparatus (for example, refer to Patent Document 2 listed below).

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-258324

[0007] Patent Document 2: Japanese Patent Application Publication No. 2005-507159 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] In the technology described in the patent document 1, the inner antenna is arranged in a circular area with a smaller radius than the outer antenna, so the inner antenna cannot be too long. In addition, in the technology described in the patent document 1, each antenna is configured to resonate at a frequency of 1 / 2 wavelength of the supplied high frequency. Therefore, depending on the size of the plasma processing device, the frequency of the high frequency supplied to the inner antenna may have to be higher than the frequency of the high frequency supplied to the outer antenna. When the frequency of the high frequency supplied to the antenna becomes higher, there is a tendency for the power of the high frequency radiated from the antenna to increase.

[0010] In addition, it is considered that in the technology described in the patent document 1, the supply of the processing gas is performed as described in the patent document 2, that is, the processing gas is supplied into the chamber from the center of the dielectric window provided with the antenna. In this case, an inner antenna is arranged near the gas pipe for supplying the processing gas. In addition, high-power high-frequency waves are radiated from the inner antenna. Therefore, abnormal discharge sometimes occurs in the gas pipe arranged in the center of the dielectric window. When abnormal discharge occurs, the inside of the gas pipe is damaged and the gas pipe is degraded. In addition, when the inside of the gas pipe is damaged, sometimes the components peeled off from the inside of the gas pipe due to abnormal discharge float in the chamber in the form of particles and adhere to the processed substrate.

[0011] Solutions for solving problems

[0012] One aspect of the present invention is a plasma processing device, which includes a chamber, a gas supply unit, an antenna, and a power supply unit. The chamber is used to accommodate a substrate to be processed. The gas supply unit supplies a processing gas into the chamber from the upper part of the chamber. The antenna is arranged above the chamber and around the gas supply unit, and generates plasma of the processing gas in the chamber by supplying high-frequency waves into the chamber. The power supply unit supplies high-frequency power to the antenna. The antenna has an inner coil and an outer coil. The inner coil is arranged around the gas supply unit in a manner surrounding the gas supply unit. The outer coil is arranged around the gas supply unit and the inner coil in a manner surrounding the gas supply unit and the inner coil. In addition, the outer coil is configured as follows: both ends of the line constituting the outer coil are open, power is supplied from the power supply unit to the midpoint of the line or near the midpoint, and the line is grounded near the midpoint, and resonates at 1 / 2 wavelength of the high-frequency power supplied from the power supply unit. In addition, the two ends of the line constituting the inner coil are connected to each other via a capacitor, and the inner coil and the outer coil are inductively coupled.

[0013] Effects of the Invention

[0014] According to various aspects and embodiments of the present invention, it is possible to suppress abnormal discharge and finely adjust the distribution of plasma density. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1This is a cross-sectional view showing an example of the outline of a plasma processing apparatus.

[0016] Figure 2 This is a schematic perspective view showing an example of an antenna.

[0017] Figure 3 It is a diagram showing an example of the arrangement of the inner coil and the outer coil.

[0018] Figure 4 This is a diagram showing an example of changes in the current flowing through the inner coil and the current flowing through the outer coil when the capacitance of the capacitor of the inner coil is changed.

[0019] Figure 5 This is a diagram showing an example of the flow direction of the current flowing through the inner coil and the flow direction of the current flowing through the outer coil.

[0020] Figure 6 This is a diagram showing an example of the distribution of ion current on a wafer.

[0021] Figure 7 This is a cross-sectional view showing an example of the structure of the gas injection portion in Example 1.

[0022] Figure 8 This is a diagram showing an example of experimental results obtained by investigating the presence or absence of discharge in a comparative example.

[0023] Fig. 9 This is a diagram showing an example of experimental results obtained by investigating the presence or absence of discharge in Example 1.

[0024] Fig.10 This is a diagram showing an example of a simulation result obtained by simulating the gas flow ejected from the gas ejection unit.

[0025] Fig.11 This is a diagram showing an example of the distribution of the mass content ratio of reaction by-products on the wafer.

[0026] Fig.12 This is a diagram showing an example of changes in the distribution of the deposition rate of reaction by-products according to the flow rate of the gas when plasma of the etching process gas is actually generated in the chamber to etch the wafer.

[0027] Fig.13 It is a diagram showing another example of the structure of the gas injection unit.

[0028] Fig.14 This is a diagram showing an example of the structure of the gas injection unit in Example 2.

[0029] Fig.15 It is a diagram showing an example of arrangement of rod-shaped shielding members.

[0030] Fig.16 This is a diagram showing an example of the reduction rate of the electric field in the gas ejection portion caused by the shielding member.

[0031] Fig.17 This is a diagram showing an example of experimental results obtained by investigating the presence or absence of discharge in Example 2.

[0032] Fig.18 It is a diagram showing another example of arrangement of the shielding member.

[0033] Fig.19 It is a diagram showing another example of arrangement of the shielding member.

[0034] Fig. 20 This is a diagram showing an example of the structure of the gas injection unit in Example 3.

[0035] Fig.21 This is a diagram showing an example of experimental results obtained by investigating the presence or absence of discharge in Example 3.

[0036] Fig. 22 It is a diagram showing another example of the structure of the gas flow path.

[0037] Description of Reference Numerals

[0038] W: wafer; 10: plasma processing device; 100: control device; 11: chamber; 21: base; 41: gas injection part; 420: shielding member; 43a, 43b: injection port; 430a, 430b: space; 53: dielectric window; 54: antenna; 541: outer coil; 542: inner coil; 543: capacitor; 61: high-frequency power supply. DETAILED DESCRIPTION

[0039] One embodiment of the disclosed plasma processing device includes a chamber, a dielectric window, a gas supply unit, an antenna, and a power supply unit. The chamber is used to accommodate a substrate to be processed. The dielectric window constitutes the upper part of the chamber. The gas supply unit supplies a processing gas into the chamber from the upper part of the chamber. The antenna is arranged above the chamber and around the gas supply unit, and generates plasma of the processing gas in the chamber by supplying high-frequency waves into the chamber. The power supply unit supplies high-frequency power to the antenna. The antenna has an inner coil and an outer coil. The inner coil is arranged around the gas supply unit in a manner surrounding the gas supply unit. The outer coil is arranged around the gas supply unit and the inner coil in a manner surrounding the gas supply unit and the inner coil. In addition, either the inner coil or the outer coil is configured such that: both ends of the line constituting one coil are open, power is supplied from the power supply unit to the midpoint of the line or near the midpoint, and the line is grounded near the midpoint, and resonates at 1 / 2 wavelength of the high-frequency power supplied from the power supply unit. In addition, in the other of the inner and outer coils, both ends of the line constituting the other coil are connected to each other via a capacitor, and the other coil is inductively coupled to the one coil.

[0040] In one embodiment of the disclosed plasma processing apparatus, the coil on one side may be formed into a substantially circular spiral shape with two or more turns, and the coil on the other side may be formed into a substantially circular ring shape. In addition, the coil on one side and the coil on the other side may be configured so that the outer shape of the coil on one side and the outer shape of the coil on the other side form concentric circles.

[0041] In addition, in one embodiment of the disclosed plasma processing device, the gas supply part can also be formed into a roughly cylindrical shape, and the coil on one side and the coil on the other side can also be configured so that the center of the outer shape of the coil on one side and the center of the outer shape of the coil on the other side are located on the central axis of the gas supply part.

[0042] In addition, in one embodiment of the disclosed plasma processing device, the coil on one side and the coil on the other side may be arranged inside the dielectric window or above the dielectric window, and the distance between the plane including the coil on one side and the lower surface of the dielectric window may be different from the distance between the plane including the coil on the other side and the lower surface of the dielectric window.

[0043] In one embodiment of the disclosed plasma processing apparatus, one coil may be an outer coil and the other coil may be an inner coil. In addition, the distance between the plane including the inner coil and the lower surface of the dielectric window may be shorter than the distance between the plane including the outer coil and the lower surface of the dielectric window.

[0044] Furthermore, in one embodiment of the disclosed plasma processing apparatus, the power supply unit may be capable of changing the frequency of the high-frequency power supplied to the antenna.

[0045] In one embodiment of the disclosed plasma processing apparatus, the capacitor provided in the other coil may be a variable capacitor.

[0046] In one embodiment of the disclosed plasma processing apparatus, a flow path through which a processing gas supplied to the chamber flows may be provided inside the gas supply unit, and a pressure in the flow path may be higher than a pressure in the chamber.

[0047] In addition, in one embodiment of the disclosed plasma processing device, the gas supply part may also have: a protrusion, which protrudes from the lower surface of the dielectric window into the chamber at the lower part of the gas supply part; a first injection port, which is arranged on the protrusion and is used to inject the processing gas in a downward direction; and a second injection port, which is arranged on the protrusion and is used to inject the processing gas in a horizontal direction or obliquely downward.

[0048] In one embodiment of the disclosed plasma processing apparatus, a conductive shield member may be provided in the gas supply unit so as to surround a space through which the processing gas passes.

[0049] In one embodiment of the disclosed plasma processing apparatus, a lower end of the shield member may be located below a lower surface of the dielectric window.

[0050] Furthermore, in one embodiment of the disclosed plasma processing apparatus, the shield member may be formed in a plate shape.

[0051] In one embodiment of the disclosed plasma processing apparatus, the shield member may be a metal film formed on an outer wall of the gas supply unit or a side wall of a space in the gas supply unit through which the processing gas passes.

[0052] Furthermore, in one embodiment of the disclosed plasma processing apparatus, the shielding member may be formed in a rod shape.

[0053] In one embodiment of the disclosed plasma processing apparatus, at least a portion of the space in the gas supply portion through which the processing gas passes may be curved so that a straight path is not formed from the first injection port and the second injection port to the upper end of the gas supply portion.

[0054] In addition, one embodiment of the disclosed plasma processing device includes a chamber, a dielectric window, a gas supply unit, an antenna, and a power supply unit. The chamber is used to accommodate a substrate to be processed. The dielectric window constitutes the upper part of the chamber. The gas supply unit supplies a processing gas into the chamber from the upper part of the chamber. The antenna is arranged above the chamber and around the gas supply unit, and generates plasma of the processing gas in the chamber by supplying high-frequency waves into the chamber. The power supply unit supplies high-frequency power to the antenna. In addition, the antenna is arranged around the gas supply unit in a manner surrounding the gas supply unit, and is configured as follows: both ends of the line constituting the antenna are open, power is supplied from the power supply unit to the midpoint of the line or near the midpoint, and it is grounded near the midpoint, and resonates at 1 / 2 wavelength of the high-frequency power supplied from the power supply unit. In addition, a conductive shielding member is provided in the gas supply unit in a manner surrounding the space through which the processing gas passes.

[0055] In one embodiment of the disclosed plasma processing apparatus, a lower end of the shield member may be located below a lower surface of the dielectric window.

[0056] Furthermore, in one embodiment of the disclosed plasma processing apparatus, the shield member may be formed in a plate shape.

[0057] In one embodiment of the plasma processing apparatus of the present disclosure, the shield member may be a metal film formed on an outer wall of the gas supply unit or a side wall of a space in the gas supply unit through which the processing gas passes.

[0058] Furthermore, in one embodiment of the disclosed plasma processing apparatus, the shielding member may be formed in a rod shape.

[0059] In addition, in one embodiment of the disclosed plasma processing device, the gas supply part may include: a protrusion, which protrudes from the lower surface of the dielectric window into the chamber at the lower part of the gas supply part; a first injection port, which is arranged on the protrusion and is used to inject the processing gas in a downward direction; and a second injection port, which is arranged on the protrusion and is used to inject the processing gas in a horizontal direction or obliquely downward, and at least a portion of the space in the gas supply part through which the processing gas passes is bent so that a straight path is not formed from the first injection port and the second injection port to the upper end of the gas supply part.

[0060] Hereinafter, embodiments of the disclosed plasma processing apparatus will be described in detail based on the accompanying drawings. In addition, the disclosed plasma processing apparatus is not limited to the following embodiments. In addition, the embodiments can be appropriately combined within the range in which the processing contents are not contradictory.

[0061] [Example 1]

[0062] [Structure of Plasma Processing Device 10]

[0063] Figure 1 1 is a cross-sectional view showing an example of the outline of the plasma processing apparatus 10. The plasma processing apparatus 10 includes a chamber 11 formed of a conductor such as aluminum. An opening 110 for carrying in and out a wafer W as an example of a substrate to be processed is provided on the side of the chamber 11, and the opening 110 can be opened and closed by a gate valve 111. The chamber 11 is grounded.

[0064] A disc-shaped susceptor 21 made of a conductive material such as aluminum is provided at the approximate center of the bottom surface side of the chamber 11, and the susceptor 21 is used to carry the wafer W as the processing object. The susceptor 21 functions as an electrode for introducing (biasing) ions in the plasma. The susceptor 21 is supported by a cylindrical susceptor support 22 formed by an insulating material. In this embodiment, the central axis of the susceptor 21 supported by the susceptor support 22 is defined as the Z axis.

[0065] In addition, the susceptor 21 is connected to a high-frequency power supply 30 for bias via a power supply rod 32 and a matching circuit 31. A high-frequency power of, for example, 13 MHz is supplied from the high-frequency power supply 30 to the susceptor 21. The frequency and power of the high-frequency power supplied from the high-frequency power supply 30 to the susceptor 21 are controlled by a control device 100 described later.

[0066] An electrostatic chuck 23 for holding the wafer W by electrostatic attraction is provided on the upper surface of the susceptor 21, and a focus ring 24 is provided on the outer periphery of the electrostatic chuck 23 to surround the wafer W. The substantially disk-shaped wafer W is placed on the electrostatic chuck 23 with its central axis aligned with the Z axis.

[0067] In addition, a flow path 212 is formed inside the susceptor 21 for passing a refrigerant such as cooling water (CW) to control the temperature of the wafer W. The flow path 212 is connected to a cooling unit (not shown) via a pipe 213, and the temperature-controlled refrigerant is supplied from the cooling unit via the pipe 213 to the flow path 212. The temperature of the refrigerant in the cooling unit is controlled by a control device 100 described later.

[0068] A gas supply path 214 is provided inside the susceptor 21 for supplying a heat transfer gas such as He gas between the upper surface of the electrostatic chuck 23 and the lower surface of the wafer W. The gas supply path 214 penetrates the electrostatic chuck 23 and has an upper end opening on the upper surface of the electrostatic chuck 23.

[0069] In addition, the base 21 is provided with lift pins which penetrate the base 21 in the vertical direction, are provided to be able to protrude and retract relative to the upper surface of the electrostatic chuck 23, and are used to transfer the wafer W to and from a transfer arm (not shown). The vertical movement of the lift pins is controlled by a control device 100 described later.

[0070] In addition, an annular partition plate 12 having a large number of through holes is provided between the outer wall of the base support portion 22 and the inner wall of the chamber 11. In addition, an exhaust port 13 is formed on the bottom surface of the chamber 11, and the exhaust port 13 is connected to an exhaust device 15 via an exhaust pipe 14. The exhaust device 15 is controlled by a control device 100 described later.

[0071] A dielectric window 53 formed of a dielectric such as quartz in a disc shape is provided at the upper part of the chamber 11. The space above the dielectric window 53 is covered by a shielding box 51 formed of a conductor such as aluminum in a cylindrical shape. The shielding box 51 is grounded via the chamber 11. An opening is formed in the center of the shielding box 51 and the dielectric window 53, and a gas injection unit 41 for supplying a processing gas into the chamber 11 is provided at the opening. The outer shape of the gas injection unit 41 is roughly cylindrical, and is provided at the opening in the center of the shielding box 51 and the dielectric window 53 in a manner that the central axis is consistent with the Z axis. The gas injection unit 41 is an example of a gas supply unit.

[0072] Inlet ports 42a and 42b for introducing the processing gas into the gas injection portion 41 are provided at the upper portion of the gas injection portion 41. The lower portion of the gas injection portion 41 protrudes downward from the lower surface of the dielectric window 53. In the lower portion of the gas injection portion 41, there are formed: an injection port 43a for injecting the processing gas downward along the Z axis; and an injection port 43b for injecting the processing gas in the lateral direction, that is, in a direction away from the Z axis. The injection port 43a is an example of a first injection port, and the injection port 43b is an example of a second injection port.

[0073] The introduction port 42a is connected to a gas supply source 44a via a valve 46a and an MFC (Mass Flow Controller) 45a. In addition, the introduction port 42b is connected to a gas supply source 44b via a valve 46b and an MFC 45b.

[0074] The MFC 45a controls the flow rate of the processing gas supplied from the gas supply source 44a. The valve 46a controls the supply and stop of the processing gas whose flow rate is controlled by the MFC 45a to the gas injection unit 41. The processing gas introduced into the gas injection unit 41 through the introduction port 42a is injected downward into the chamber 11 from the injection port 43a.

[0075] The MFC 45b controls the flow rate of the processing gas supplied from the gas supply source 44b. The valve 46a controls the supply and supply stop of the processing gas whose flow rate is controlled by the MFC 45a to the gas injection unit 41. The processing gas introduced into the gas injection unit 41 through the introduction port 42b is injected into the chamber 11 in a lateral direction from the injection port 43b. The MFCs 45a and 45b and the valves 46a and 46b are independently controlled by the control device 100 described later.

[0076] In this embodiment, the gas supply sources 44a and 44b supply etching processing gas such as CF4 gas and chlorine gas as processing gas into the chamber 11. Alternatively, the gas supply sources 44a and 44b may supply respective processing gases into the chamber 11.

[0077] An antenna 54 for generating plasma is housed in a space above the chamber 11 and surrounded by the dielectric window 53 and the shield box 51. The antenna 54 includes an outer coil 541 and an inner coil 542. The inner coil 542 is disposed around the gas injection portion 41 in a manner to surround the gas injection portion 41. The outer coil 541 is disposed around the gas injection portion 41 and the inner coil 542 in a manner to surround the gas injection portion 41 and the inner coil 542. The outer coil 541 and the inner coil 542 are supported by a support mechanism (not shown) so as to be disposed above the dielectric window 53 in a manner to be separated from the dielectric window 53. In addition, the outer coil 541 and the inner coil 542 are not limited to being separated from the dielectric window 53, and either or both of the outer coil 541 and the inner coil 542 may be in contact with the upper surface of the dielectric window 53. In addition, either or both of the outer coil 541 and the inner coil 542 may be formed inside the dielectric window 53.

[0078] [Structure of Antenna 54]

[0079] Figure 2 : is a schematic perspective view showing an example of the antenna 54. Figure 2 As shown, the outer coil 541 is formed into a substantially circular spiral shape with more than two turns, and is arranged above the dielectric window 53 in such a way that the central axis of the outer shape of the outer coil 541 coincides with the Z axis. Figure 2 As shown, the inner coil 542 is formed in a substantially circular ring shape, and is arranged above the dielectric window 53 so that the central axis of the inner coil 542 coincides with the Z axis.

[0080] In the present embodiment, the outer coil 541 and the inner coil 542 are planar coils, and are arranged at a position above the lower surface of the dielectric window 53, which is the boundary surface with the plasma generation space, in a manner substantially parallel to the surface of the wafer W placed on the electrostatic chuck 23. In addition, in the present embodiment, the distance between the outer coil 541 and the lower surface of the dielectric window 53 is different from the distance between the inner coil 542 and the lower surface of the dielectric window 53. For example, the distance between the inner coil 542 and the lower surface of the dielectric window 53 is shorter than the distance between the outer coil 541 and the lower surface of the dielectric window 53. In addition, as another example, the distance between the outer coil 541 and the upper surface of the dielectric window 53 and the distance between the inner coil 542 and the upper surface of the dielectric window 53 may be the same distance. In addition, the distance between the outer coil 541 and the upper surface of the dielectric window 53 may be longer than the distance between the inner coil 542 and the upper surface of the dielectric window 53. Furthermore, the distance between the outer coil 541 and the lower surface of the dielectric window 53 and the distance between the inner coil 542 and the lower surface of the dielectric window 53 may be independently changed by a driving unit (not shown).

[0081] Figure 3 1 is a diagram showing an example of the arrangement of the inner coil 542 and the outer coil 541 . Figure 3 1 is a diagram showing an example of the configuration of the inner coil 542 and the outer coil 541 when viewed from the direction along the Z axis. The inner coil 542 is formed into a circle with a radius r3, and is configured so that the center of the circle coincides with the Z axis. In this embodiment, the radius r3 is, for example, a length of 75 mm or less.

[0082] The outer coil 541 is formed in a substantially circular spiral shape in the area between the circle of radius r1 and the circle of radius r2. The outer coil 541 is configured so that the center of the circle of radius r1 and the center of the circle of radius r2 coincide with the Z axis. That is, the outer coil 541 and the inner coil 542 are configured so that the outer shape of the outer coil 541 and the outer shape of the inner coil 542 form concentric circles. In the present embodiment, the radius r1 is, for example, 140 mm, and the radius r2 is, for example, 210 mm.

[0083] Both ends of the line constituting the outer coil 541 are open. In addition, the midpoint of the line constituting the outer coil 541 or the vicinity of the midpoint is connected to the high-frequency power supply 61, and high-frequency power is supplied from the high-frequency power supply 61 to the outer coil 541. The high-frequency power supply 61 is an example of a power supply unit. In addition, the vicinity of the midpoint of the line constituting the outer coil 541 is grounded. The outer coil 541 is configured to resonate at λ / 2 with respect to the wavelength λ of the high-frequency power supplied from the high-frequency power supply 61. That is, the outer coil 541 functions as a planar spiral resonator. The voltage generated by the line constituting the outer coil 541 is distributed as follows: the minimum near the midpoint of the line and the maximum at both ends of the line. In addition, the current generated by the line constituting the outer coil 541 is distributed as follows: the maximum near the midpoint of the line and the minimum at both ends of the line. The high-frequency power supply 61 that supplies high-frequency power to the outer coil 541 can change the frequency and power. The frequency and power of the high-frequency power supplied from the high-frequency power supply 61 to the outer coil 541 are controlled by the control device 100 described later.

[0084] Regarding the inner coil 542, both ends of the line constituting the inner coil 542 are connected via a capacitor 543. In the present embodiment, the capacitor 543 is a variable capacitor. In addition, the capacitor 543 may also be a capacitor having a fixed capacity. The inner coil 542 is inductively coupled with the outer coil 541, and a current flows in the inner coil 542 in a direction that cancels out the magnetic field generated by the current flowing in the outer coil 541. By controlling the capacity of the capacitor 543, the direction and magnitude of the current flowing in the inner coil 542 can be controlled in accordance with the current flowing in the outer coil 541. The capacity of the capacitor 543 is controlled by the control device 100 described later.

[0085] The current flowing through the outer coil 541 and the current flowing through the inner coil 542 generate a magnetic field in the Z-axis direction, and the generated magnetic field generates an induced electric field in the chamber 11. The induced electric field generated in the chamber 11 converts the processing gas supplied from the gas injection unit 41 into plasma. Then, the wafer W on the electrostatic chuck 23 is subjected to a predetermined process such as etching by using the ions and active species included in the plasma.

[0086] Here, it is considered to configure a planar spiral resonator of the same size as the inner coil 542 on the inner side of the outer coil 541 (on the gas injection unit 41 side) instead of the inner coil 542. The area inside the outer coil 541 is narrower than the area where the outer coil 541 is configured, so it is difficult to configure a line of the same length as the line constituting the outer coil 541 in the area inside the outer coil 541. Therefore, the line constituting the planar spiral resonator (hereinafter referred to as the inner resonator) configured in the area inside the outer coil 541 can only be shorter than the line constituting the outer coil 541. When the line becomes shorter, the resonant frequency becomes higher, so the resonant frequency of the inner resonator can only be higher than the resonant frequency of the outer coil 541. When the frequency becomes higher, the energy of the electromagnetic wave radiated from the coil becomes larger.

[0087] In addition, a gas injection portion 41 is arranged inside the inner resonator, and the inner resonator is close to the gas injection portion 41. Therefore, the electromagnetic wave radiated from the inner resonator invades the space inside the gas injection portion 41 through which the process gas flows. When the resonance frequency of the inner resonator becomes higher, the energy of the electromagnetic wave radiated from the inner resonator becomes larger, and thus the electromagnetic wave with greater energy invades the space inside the gas injection portion 41 through which the process gas flows. Therefore, abnormal discharge sometimes occurs in the space inside the gas injection portion 41 through which the process gas flows.

[0088] It is considered that the energy of the electromagnetic wave intruding from the inner resonator to the space inside the gas injection part 41 can be suppressed by separating the inner resonator from the gas injection part 41. However, when the inner resonator is arranged to be separated from the Z axis, it is difficult to independently control the plasma in the area near the Z axis and the plasma in the area away from the Z axis. Therefore, the inner resonator that helps control the plasma near the Z axis can only be arranged near the gas injection part 41. Therefore, when the inner resonator is used, it is difficult to avoid abnormal discharge in the space inside the gas injection part 41 where the process gas flows.

[0089] In contrast, in this embodiment, a planar spiral resonator is not arranged inside the outer coil 541 (on the gas injection unit 41 side), but a ring-shaped inner coil 542 whose two ends are connected via a capacitor 543 is arranged. The inner coil 542 does not resonate using high-frequency power supplied directly, but generates an induced current corresponding to the magnetic field generated by the current flowing through the outer coil 541. Therefore, regardless of the length of the line constituting the inner coil 542, a current having the same frequency as the frequency of the current flowing through the outer coil 541 flows through the inner coil 542. Therefore, even in the case where the length of the line constituting the inner coil 542 is shorter than the length of the line constituting the outer coil 541, a current having the same frequency as the frequency of the current flowing through the outer coil 541 can be generated in the inner coil 542.

[0090] The area where the outer coil 541 is arranged is wider than the area inside the outer coil 541, so a relatively long line can be used as a line constituting the outer coil 541. Therefore, the outer coil 541, which functions as a planar spiral resonator, can resonate at a relatively low frequency. Therefore, a current with a relatively low frequency, which is the same as the frequency of the current flowing in the outer coil 541, is generated in the inner coil 542. Thus, the energy of the electromagnetic wave radiated from the inner coil 542 is suppressed, and the energy of the electromagnetic wave intruding into the gas injection unit 41 is suppressed. Thus, abnormal discharge in the space inside the gas injection unit 41 can be suppressed.

[0091] return Figure 1 The description will be continued. The plasma processing apparatus 10 has a control device 100, which controls each part of the plasma processing apparatus 10. The control device 100 has a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and a processor such as a CPU (Central Processing Unit). The memory in the control device 100 stores data such as processes, programs, etc. The processor in the control device 100 reads out the program stored in the memory in the control device 100 and executes the program, and controls each part of the plasma processing apparatus 10 based on the data such as processes stored in the memory in the control device 100.

[0092] [Current Flowing in the Outer Coil 541 and the Inner Coil 542]

[0093] Figure 4 This is a diagram showing an example of changes in the current flowing through the inner coil 542 and the outer coil 541 when the capacitance of the capacitor 543 of the inner coil 542 is changed. Figure 4 2 shows changes in the current flowing through each of the inner coil 542 and the outer coil 541 when the capacitance of the capacitor 543 is changed in a range of 10 pF to 100 pF by a stepping motor in a range of 0 to 19200 steps.

[0094] Figure 4 The main conditions for the experimental results shown are as follows.

[0095] Pressure in chamber 11: 100mT

[0096] Processing gas: Ar / CF4=70 / 10sccm

[0097] High frequency power supplied to the outer coil 541: 1000W

[0098] The frequency of the high-frequency power supplied to the outer coil 541 is 27 MHz.

[0099] For example Figure 4 As shown in FIG. 1 , as the capacitance of the capacitor 543 increases from 10 pF (capacity corresponding to 0 steps), the energy supplied from the outer coil 541 to the inner coil 542 by electromagnetic induction increases, and the current flowing in the inner coil 542 increases. On the other hand, as the energy supplied to the inner coil 542 increases, the energy of the outer coil 541 decreases, and thus the current flowing in the outer coil 541 decreases. Furthermore, when the capacitance of the capacitor 543 becomes close to the capacitance corresponding to 12200 steps, the current flowing in the inner coil 542 is the largest, and the current flowing in the outer coil 541 becomes the same as the current flowing in the inner coil 542.

[0100] Furthermore, when the capacity of the capacitor 543 is further increased from the capacity corresponding to 12200 steps to the capacity corresponding to 12400 steps, the polarity of the current flowing through the inner coil 542 is reversed, and a large current flows in the reverse direction. This is because, for example, Figure 5 As shown in (a), at a capacity from 0 steps to about 12200 steps, the direction of the current flowing in the outer coil 541 is the same as the direction of the current flowing in the inner coil 542 (in phase), for example Figure 5 As shown in (b), at a capacity from approximately 12400 steps to 19200 steps, the direction of the current flowing in the outer coil 541 is opposite to the direction of the current flowing in the inner coil 542 (in phase).

[0101] Figure 6 : is a diagram showing an example of the distribution of ion current on a wafer. The ion current is measured radially from the center of the wafer W toward the outer periphery of the wafer W using a planar Langmuir probe. Figure 6 , the ion current at the center of the wafer W is normalized to 1, and the distribution of the ion current corresponding to the capacitance of the capacitor 543 corresponding to each step is shown. The magnitude of the ion current on the wafer W is related to the density of the plasma on the wafer W. Therefore, the distribution of the ion current on the wafer W corresponds to the distribution of the plasma density on the wafer W.

[0102] Reference Figure 6 , at the capacitance of capacitor 543 corresponding to step 0, the ion current slightly outside the center of wafer W becomes slightly larger. Moreover, as the capacitance of capacitor 543 increases, the ion current near the center of wafer W becomes relatively larger. This is believed to be because: Figure 5As shown in (a), the current flowing in the outer coil 541 and the current flowing in the inner coil 542 are in the same direction (in phase), and the induced electric fields generated by the magnetic fields generated by each coil reinforce each other, so the ion current near the center of the wafer W increases.

[0103] On the other hand, when the capacitance of the capacitor 543 becomes the capacitance corresponding to 12400 steps, the ion current near the center of the wafer W becomes relatively small. This is considered to be because, for example Figure 5 As shown in (b), the current flowing in the outer coil 541 and the current flowing in the inner coil 542 are in opposite directions (opposite phases), and the induced electric fields generated by the magnetic fields generated by each coil weaken each other, so that the ion current near the center of the wafer W is reduced.

[0104] In this way, by controlling the capacitance of the capacitor 543 connected to the inner coil 542 , the distribution of the plasma density in the radial direction centered on the Z axis on the wafer W can be controlled. Thus, the accuracy of the process on the wafer W can be improved.

[0105] [Structure of Gas Injection Unit 41]

[0106] Figure 7 4 is a cross-sectional view showing an example of the structure of the gas injection portion 41 in Example 1. The gas injection portion 41 is formed of a dielectric such as ceramics, quartz, etc., and has a substantially cylindrical shape. The gas injection portion 41 is embedded in an opening formed in the center of the shield box 51 and the dielectric window 53, and is fixed to the dielectric window 53 by a screw 411. The gas injection portion 41 is fixed to the dielectric window 53 in a manner such that the central axis coincides with the Z axis. The lower portion 410 of the gas injection portion 41 protrudes further below the dielectric window 53 than the lower surface of the dielectric window 53. The lower portion 410 of the gas injection portion 41 is an example of a protruding portion.

[0107] A plurality of injection ports 43a and a plurality of injection ports 43b are formed in the lower portion 410 of the gas injection portion 41. The plurality of injection ports 43a are formed on the lower surface of the gas injection portion 41 and on a circumference centered on the Z axis, and inject the processing gas downward. In addition, the plurality of injection ports 43b are formed on the side wall of the lower portion 410 of the gas injection portion 41, and are used to inject the processing gas in the lateral direction.

[0108] The processing gas supplied through the inlet 42a passes through the substantially cylindrical space 430a with the Z axis as the center axis and is ejected downward from the ejection port 43a. In addition, the processing gas supplied through the inlet 42b passes through the space 430b provided around the space 430a and is ejected radially from the plurality of ejection ports 43b with the Z axis as the center. The space 430a and the space 430b are an example of a flow path for the processing gas supplied to the chamber 11 to flow.

[0109] In addition, a transparent window 421 made of quartz or the like is provided on the upper part of the gas injection part 41. The presence or absence of discharge in the space 430a can be detected by using the window 421. In addition, the intensity and wavelength of light emitted from the plasma in the chamber 11 can also be observed through the space 430a and each injection port 43a by using the window 421.

[0110] [Experimental results]

[0111] Next, an experiment was conducted on abnormal discharge that occurs in the gas injection unit 41 when plasma is generated in the chamber 11 . Figure 8 This is a diagram showing an example of experimental results obtained by investigating the presence or absence of discharge in a comparative example. Figure 8 (a) shows the experimental results when the pressure in the chamber 11 is 10 mT. Figure 8 (b) shows the experimental results when the pressure in the chamber 11 is 100 mT. Figure 8 (c) shows the experimental results when the pressure in the chamber 11 is 400 mT. In the comparative example, the experiment was conducted by arranging an inner resonator in place of the inner coil 542 instead of the inner coil 542. In the experiment, high-frequency power was not applied to the outer coil 541.

[0112] The main conditions of the experiments in the comparative examples are as follows.

[0113] Pressure in chamber 11: 10mT~400mT

[0114] Gas used: Ar = 100 sccm ~ 1500 sccm

[0115] High frequency power supplied to the inner resonator: 100W to 650W

[0116] Frequency of high-frequency power supplied to the inner resonator: 60MHz

[0117] exist Figure 8 In the figure, the condition where no abnormal discharge occurs is indicated by ○, and the condition where abnormal discharge occurs is indicated by ×. Figure 8 As shown, in the comparative example using the inner resonator instead of the inner coil 542, abnormal discharge occurred in the gas injection part 41 under almost all conditions. In addition, the pressure in the spaces 430a and 430b of the gas injection part 41 was much higher than the pressure in the chamber 11, and became a pressure between 3 Torr and 25 Torr.

[0118] Fig. 9 This is a diagram showing an example of experimental results obtained by investigating the presence or absence of discharge in Example 1. Fig. 9(a) shows the experimental results when the pressure in the chamber 11 is 10 mT. Fig. 9 (b) shows the experimental results when the pressure in the chamber 11 is 100 mT. Fig. 9 (c) shows the experimental results when the pressure in the chamber 11 is 400 mT.

[0119] Fig. 9 The main conditions for the experimental results shown are as follows.

[0120] Pressure in chamber 11: 10mT~400mT

[0121] Gas used: Ar = 100 sccm ~ 1500 sccm

[0122] High frequency power supplied to the outer coil 541: 100W to 2000W

[0123] Frequency of high-frequency power supplied to outer coil 541: 27 MHz

[0124] In addition, the capacitor 543 connected to the inner coil 542 is set to Figure 4 The capacity corresponding to 12200 steps is shown for the experiments.

[0125] For example Fig. 9 As shown in FIG. 1 , in all conditions, no abnormal discharge occurred in the gas injection unit 41. Thus, by configuring the inner coil 542 inside the outer coil 541, abnormal discharge in the gas injection unit 41 can be suppressed. Figure 6 As shown, by controlling the capacitance of the capacitor 543 of the inner coil 542 , the distribution of the plasma density on the wafer W can be adjusted.

[0126] [Simulation of Gas Flow Injected from Gas Injection Section 41]

[0127] Furthermore, in this embodiment, for example Figure 7 As shown, a plurality of injection ports 43 a for injecting gas downward and a plurality of injection ports 43 b for injecting gas in a lateral direction are provided in the lower portion 410 of the gas injection portion 41 . Fig.10 1 is a diagram showing an example of a simulation result obtained by simulating the flow of gas injected from the gas injection unit 41 . Fig.10 (a) shows the simulation result of the gas flow ejected downward from the plurality of ejection ports 43a, Fig.10 (b) shows the simulation result of the gas flow injected in the lateral direction from the plurality of injection ports 43b.

[0128] The main conditions of the simulation are as follows.

[0129] Pressure in chamber 11: 50 mT

[0130] Gas used: Ar = 500 sccm

[0131] Reaction byproducts: SiCl4 = 50 sccm (entire surface of wafer W)

[0132] In addition, the reaction byproducts are particles generated from the plasma of the etching process gas when etching the wafer W, and substances generated secondarily by reacting with the wafer W. In the simulation, it is assumed that the compound of silicon contained in the wafer W and the halogen contained in the etching process gas, that is, SiCl4, is the reaction byproduct, and the reaction byproduct is uniformly supplied from the entire surface of the wafer W into the chamber 11.

[0133] In the case of a gas injection in a downward direction, e.g. Fig.10 As shown in (a), near the center of the wafer W, a strong gas flow is generated from the center toward the edge of the wafer W. Therefore, it is believed that the reaction by-products generated can be efficiently removed near the center of the wafer W. However, it is believed that the gas flow is weak near the edge of the wafer W, and the removal effect of the reaction by-products near the edge is low.

[0134] On the other hand, when the gas is ejected in the lateral direction, for example Fig.10 As shown in (b), a strong gas flow is generated near the edge of the wafer W, but a weak gas flow is generated near the center of the wafer W. Therefore, it is believed that the generated reaction by-products can be efficiently removed near the edge of the wafer W, and the removal effect of the reaction by-products is low near the center of the wafer W.

[0135] Fig.11 This is a diagram showing an example of the distribution of the mass content ratio of reaction by-products on the wafer. Fig.11 (a) shows the distribution of the mass content ratio of the reaction by-products on the wafer W when the flow rate of the Ar gas is 500 sccm. Fig.11 (b) shows the distribution of the mass content ratio of the reaction by-products on the wafer W when the flow rate of the Ar gas is 45 sccm.

[0136] For example, according to Fig.11 As can be clearly seen in (a), when the gas is ejected downward from the ejection port 43a, the content ratio of the reaction by-products near the center of the wafer W is lower than that near the edge of the wafer W, and the reaction by-products can be removed more efficiently near the center of the wafer W than near the edge. On the other hand, when the gas is ejected horizontally from the ejection port 43b, the content ratio of the reaction by-products near the edge of the wafer W is lower than that near the center of the wafer W, and the reaction by-products can be removed more efficiently near the edge of the wafer W than near the center.

[0137] according to Fig.11 As a result of (a), by combining the gas injection from the injection port 43a downward and the gas injection from the injection port 43b in the lateral direction, a strong gas flow can be generated near the center and near the edge of the wafer W. As a result, the reaction byproducts generated on the wafer W can be removed efficiently. In addition, when the flow rate of the injected gas is small, for example Fig.11 As shown in (b), regardless of the direction of the gas injection, the overall content ratio of the reaction by-products increases, and the removal effect of the reaction by-products is low. Therefore, it is necessary to inject a large flow rate of gas from the injection ports 43a and 43b.

[0138] [Process Influence of Gas Flow Injected from Gas Injection Unit 41]

[0139] Fig.12 1 is a diagram showing an example of a change in the distribution of the deposition rate of the reaction byproducts corresponding to the flow rate of the gas when the plasma of the etching process gas is actually generated in the chamber 11 to etch the wafer. At this time, the material of the wafer W is silicon, Cl2, HBr, Ar, and O2 are used as the etching process gas, and the reaction byproduct is SiOClBr. Through etching, the reaction byproducts are released from the surface of the wafer W into the chamber 11, and a part of the reaction byproducts is reattached to the wafer W. Therefore, the amount of the reaction byproducts reattached to the wafer W is measured as the deposition rate. Fig.12 (a) shows the distribution of the deposition rate of the reaction by-products when the gas is sprayed in the downward direction, Fig.12 (b) shows the distribution of the deposition rate of the reaction byproducts when the gas is sprayed in the lateral direction. Fig.12 (c) shows, as a comparative example, the distribution of the deposition rate of the reaction by-products when the gas is injected toward the Z axis from the side wall of the chamber 11 . Fig.12 The flow rate shown indicates the flow rate of the process gas for etching, and the reference flow rate is 500 sccm.

[0140] When the flow rate of the gas injected in the downward direction increases, e.g. Fig.12 As shown in (a), the deposition rate of the reaction byproducts decreases significantly near the center of the wafer W, but the deposition rate of the reaction byproducts near the edge of the wafer W remains almost unchanged. On the other hand, when the flow rate of the gas injected in the lateral direction increases, for example Fig.12 As shown in (b), the deposition rate of the reaction by-products decreases significantly near the edge of the wafer W, but the deposition rate of the reaction by-products near the center of the wafer W hardly changes.

[0141] The deposition rate of the reaction by-products is proportional to the residual amount of the reaction by-products retained near them, so according to Fig.12 (a) and Fig.12 The result of (b) also indicates that by combining the gas injection downward from the injection port 43a with the gas injection horizontally from the injection port 43b, the reaction byproducts can be efficiently removed near both the center and the edge of the wafer W.

[0142] In addition, when the gas is ejected from the side wall of the chamber 11 toward the Z axis, for example Fig.12 As shown in (c), if the flow rate of the injected gas is small, the deposition rate is high between the center and the edge of the wafer W. As the flow rate of the injected gas increases, the deposition rate near the edge of the wafer W decreases, and the deposition rate near the center increases. This is considered to be because the gas is injected from the side wall of the chamber 11, so the reaction byproducts near the edge of the wafer W are pushed toward the center of the wafer W as the gas flow rate increases. Therefore, when the gas is injected from the side wall of the chamber 11 toward the Z axis, it is difficult to efficiently remove the reaction byproducts on the wafer W as a whole.

[0143] The first embodiment is described above. As is clear from the above description, according to the plasma processing apparatus 10 of this embodiment, abnormal discharge can be suppressed and the distribution of plasma density can be finely adjusted. In addition, in this embodiment, the processing gas is injected downward and horizontally from the gas injection part 41 provided in the upper center of the chamber 11, thereby efficiently removing the reaction byproducts generated on the wafer W.

[0144] Furthermore, in the embodiment 1, for example Figure 7 As shown in FIG. 1 , each injection port 43 b injects the processing gas in the lateral direction, but the disclosed technology is not limited to this. Fig.13 As shown, each injection port 43b is configured to inject the processing gas in a direction away from the Z axis and obliquely downward. Fig.13 It is a diagram showing another example of the structure of the gas injection unit 41 .

[0145] [Example 2]

[0146] In the first embodiment, the abnormal discharge in the gas injection part 41 is suppressed by providing the inner coil 542 inside the outer coil 541. In contrast, in the second embodiment, the abnormal discharge in the gas injection part 41 is suppressed by arranging a shielding member around the space in the gas injection part 41 through which the processing gas flows.

[0147] [Structure of Gas Injection Unit 41]

[0148] Fig.141 is a diagram showing an example of the structure of the gas injection unit 41 in Example 2. In addition, in addition to the aspects to be described below, Fig.14 The components shown are marked with Figure 7 Components with the same reference numerals as those shown have the same Figure 7 The functions of the components described above are the same as those of the components described above, and thus detailed description thereof will be omitted.

[0149] In the gas injection unit 41 of the present embodiment, for example Fig.14 As shown in FIG. 1 , a plate-shaped shielding member 420 is provided on the side wall of the space 430a in the gas injection section 41. The shielding member 420 is formed of a non-magnetic conductive metal such as titanium. The lower end of the shielding member 420 extends to a position below the lower surface of the dielectric window 53. For example, the shielding member 420 is a metal film formed by spraying titanium or the like on the side wall of the space 430a in the gas injection section 41. The space 430a in the gas injection section 41 is substantially cylindrical, so the shielding member 420 is formed in a cylindrical shape.

[0150] The shield member 420 is provided on the side wall of the space 430a in the gas injection unit 41, thereby suppressing the electromagnetic waves generated by the antenna 54 from entering the space 430a. In this way, abnormal discharge in the space 430a is suppressed. Fig.14 In the example shown in FIG. 4 , the shielding member 420 is provided on the side wall constituting the space 430 a , but the shielding member 420 may also be provided on the side wall of each space 430 b .

[0151] In addition, Fig.14 In the example, a plate-shaped shielding member 420 is provided on the side wall constituting the space 430a. However, as another example, a plurality of shielding members 420 formed in a rod shape may be arranged around the space 430a. Fig.15 1 is a diagram showing an example of arrangement of the rod-shaped shielding member 420 . Fig.15 This is a cross-sectional view of the gas injection unit 41 as viewed from the direction of the Z axis. Fig.15 In the example, eight shielding members 420 formed in a rod shape are embedded between adjacent spaces 430b, but more than eight shielding members 420 may be arranged around the space 430a. When more than eight shielding members 420 are arranged around the space 430a, the shielding members 420 may be embedded in the side wall outside the space 430b in addition to being embedded between adjacent spaces 430b. Thus, abnormal discharge in the space 430b can be suppressed.

[0152] Fig.16 4 is a diagram showing an example of the electric field reduction rate of the gas injection unit 41 caused by the shield member 420. Fig.16, the simulation results of simulating the reduction rate of the electric field intensity when the shielding member 420 of each type is provided are shown, based on the electric field intensity acting on the area of ​​the lower portion 410 of the gas injection unit 41 including the space 430a and the space 430b when the shielding member 420 is not provided. Fig.16 In the example, an inner resonator is used instead of the inner coil 542, and a high-frequency power of 60 MHz and 1 kW is supplied to the inner resonator to cause resonance at 1 / 2 wavelength. Fig.16 The upper, middle and lower parts shown in the figure represent the upper, middle and lower parts of the lower part 410 area of ​​the gas injection part 41, respectively. Fig.16 For example, Fig.14 The thickness of the cylindrical shield member 420 (cylindrical shield) shown in the example is set to 0.5 mm. Fig.15 The simulation was performed with the diameter of the rod-shaped shield member 420 (rod-shaped shield) being 2 mm.

[0153] For example Fig.16 As shown, in any shielding member 420, the electric field intensity acting on the region of the lower portion 410 of the gas ejection portion 41 is reduced, and a shielding effect is achieved. In addition, the cylindrical shielding member has a higher overall shielding effect than the rod-shaped shielding member. In addition, with respect to the rod-shaped shielding member, the more the number of rod-shaped shielding members, that is, the narrower the interval between the rod-shaped shielding members, the higher the shielding effect becomes.

[0154] Fig.17 This is a diagram showing an example of experimental results obtained by investigating the presence or absence of discharge in Example 2. Fig.17 (a) shows the experimental results when the pressure in the chamber 11 is 10 mT. Fig.17 (b) shows the experimental results when the pressure in the chamber 11 is 100 mT. Fig.17 (c) shows the experimental results when the pressure in the chamber 11 is 400 mT. Fig.17 In the experiments shown, the Fig.14 The gas injection unit 41 of the structure shown uses an inner resonator instead of the inner coil 542. In addition, high-frequency power is not applied to the outer coil 541.

[0155] Fig.17 The main conditions for the experimental results shown are as follows.

[0156] Pressure in chamber 11: 10mT~400mT

[0157] Gas used: Ar = 100 sccm ~ 1500 sccm

[0158] High frequency power supplied to the inner resonator: 100W to 650W

[0159] Frequency of high-frequency power supplied to the inner resonator: 60MHz

[0160] For example Fig.17 As shown in FIG. 1 , even when the inner resonator is provided near the gas injection portion 41, the gas injection portion 41 has a similar structure to the experimental results (see FIG. 1 ) in which the shielding member 420 is not provided. Figure 8 ), the occurrence of abnormal discharge can be greatly suppressed in the gas injection unit 41 of the second embodiment in which the shield member 420 is arranged inside. In this way, by arranging the shield member 420 around the gas injection unit 41 and the space through which the process gas flows, even if an inner resonator is arranged near the body injection unit 41, abnormal discharge in the gas injection unit 41 can be suppressed. In addition, by arranging the inner resonator instead of the inner coil 542, abnormal discharge in the gas injection unit 41 can also be suppressed.

[0161] In the second embodiment, a plate-shaped shielding member 420 (see Fig.14 ), rod-shaped shielding member 420 (refer to Fig.15 ), but the configuration of the shielding member 420 is not limited thereto. Fig.18 As shown in FIG. 1 , the plate-shaped shielding member 420 is embedded in the side wall of the gas injection portion 41 so as to surround the spaces 430a and 430b. Fig.19 As shown, a shielding member 420 is provided on the outer wall of the gas injection portion 41. Alternatively, for example, a metal film of the shielding member 420 may be formed by spraying a metal constituting the shielding member 420 onto the side wall of the gas injection portion 41, and then ceramics or the like may be sprayed onto the surface of the shielding member 420.

[0162] [Example 3]

[0163] When the space in the gas injection portion 41 through which the processing gas flows expands linearly in the Z-axis direction, electrons are easily accelerated in the Z-axis direction, and abnormal discharge is easily generated in the space in the gas injection portion 41. Therefore, in Example 3, the space in the gas injection portion 41 is configured so that the length of the space in the gas injection portion 41 that expands linearly in the Z-axis direction becomes shorter.

[0164] Fig. 20 1 is a diagram showing an example of the structure of the gas injection unit 41 in Example 3. In addition, in addition to the aspects to be described below, Fig. 20 The components shown are marked with Figure 7 Components with the same reference numerals as those shown have the same Figure 7The functions of the components described above are the same as those of the components described above, and thus detailed description thereof will be omitted.

[0165] For example Fig. 20 As shown in the figure, the space 430a through which the gas injected from the injection port 43a flows is formed to be at least partially curved so that a straight path is not formed from the injection port 43a to the upper end of the gas injection portion 41. Similarly, the space 430b through which the gas injected from the injection port 43b flows is also formed to be at least partially curved so that a straight path is not formed from the injection port 43b to the upper end of the gas injection portion 41. The spaces 430a and 430b form a so-called labyrinth structure.

[0166] Fig.21 This is a diagram showing an example of experimental results obtained by investigating the presence or absence of discharge in Example 3. Fig.21 (a) shows the experimental results when the pressure in the chamber 11 is 10 mT. Fig.21 (b) shows the experimental results when the pressure in the chamber 11 is 100 mT. Fig.21 (c) shows the experimental results when the pressure in the chamber 11 is 400 mT. Fig.21 In the experiments shown, the Fig. 20 The gas injection unit 41 of the structure shown uses an inner resonator instead of the inner coil 542. In addition, high-frequency power is not applied to the outer coil 541.

[0167] Fig.21 The main conditions for the experimental results shown are as follows.

[0168] Pressure in chamber 11: 10mT~400mT

[0169] Gas used: Ar = 100 sccm ~ 1500 sccm

[0170] High frequency power supplied to the inner resonator: 100W to 650W

[0171] Frequency of high-frequency power supplied to the inner resonator: 60MHz

[0172] For example Fig.21 As shown in FIG. 1 , even when an inner resonator is provided near the gas injection portion 41, the space inside the gas injection portion 41 is not the gas injection portion 41 having a maze structure (see FIG. 1 ). Figure 7 ) experimental results (refer to Figure 8), the occurrence of abnormal discharge is greatly suppressed in the gas injection unit 41 of this embodiment in which the space in the gas injection unit 41 is a labyrinth structure. In this way, by setting the space in the gas injection unit 41 for the process gas to flow in a labyrinth structure, even if an inner resonator is provided near the gas injection unit 41, abnormal discharge in the gas injection unit 41 can be suppressed. In addition, by providing an inner resonator instead of the inner coil 542, abnormal discharge in the gas injection unit 41 can also be suppressed.

[0173] In addition, the spaces 430a and 430b for the processing gas to flow in the gas injection unit 41 may also be as follows. Fig. 22 As shown in the figure, the flow path of the gas from the injection port 43a and the injection port 43b to the upper end of the gas injection part 41 is formed in a spiral shape.

[0174] [other]

[0175] In addition, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the gist of the invention.

[0176] In the above-mentioned embodiments, the processing gas is supplied to the chamber 11 from the gas injection portion 41 disposed approximately in the center of the dielectric window 53. However, in addition to the gas injection portion 41, a plurality of injection ports for injecting the processing gas toward the Z-axis may be circumferentially disposed along the side wall of the chamber 11.

[0177] In the above-mentioned second and third embodiments, each injection port 43b may also be Fig.13 As shown in the figure, the processing gas is ejected in a direction away from the Z axis and obliquely downward.

Claims

1. A plasma processing device, comprising: a plasma processing chamber; a substrate support disposed in the plasma processing chamber; a dielectric window disposed above the substrate support, the dielectric window having a first central opening; A conductive shielding box having a top and side walls, wherein the top is arranged above the dielectric window, the side walls extend from the dielectric window to the top, the conductive shielding box having an inner space defined by the dielectric window, the top and the side walls, and the top having a second central opening vertically overlapping the first central opening; a central gas injection portion extending vertically through the first central opening of the dielectric window and the second central opening of the conductive shielding box and configured to supply processing gas into the plasma processing chamber, the central gas injection portion being formed of a dielectric material; An antenna is disposed in the inner space of the conductive shielding box in a manner of surrounding the central gas injection portion, and the antenna has: an outer coil having a first open end and a second open end, the outer coil having a first intermediate point and a second intermediate point between the first open end and the second open end, the first intermediate point being connected to a ground potential, the first open end being disposed closer to the central gas jet than the second open end, the outer coil having a first radius from a central axis of the central gas jet to the first open end; and an inner coil disposed between the central gas jet and the outer coil, the inner coil being inductively coupled to the outer coil, the inner coil having a second radius from a central axis of the central gas jet to the inner coil, the second radius being smaller than the first radius; and A power source is connected to the second intermediate point of the outer coil.

2. The plasma processing apparatus according to claim 1, wherein: The inner coil includes a variable capacitor.

3. The plasma processing apparatus according to claim 2, wherein: The conductive shielding box is connected to a ground potential.

4. The plasma processing apparatus according to claim 3, wherein: The outer coil is wound in a substantially circular spiral shape for more than two turns.

5. The plasma processing apparatus according to claim 1, wherein: The central gas injection portion has: a lower protrusion protruding downward from the dielectric window, wherein the lower protrusion has a first injection port configured to inject the processing gas downward into the plasma processing chamber and a second injection port configured to inject the processing gas laterally or obliquely into the plasma processing chamber; and An upper protrusion protrudes upward from the top of the conductive shield box, wherein the upper protrusion has a gas introduction port.

6. The plasma processing apparatus according to claim 5, wherein: The central gas injection portion has a substantially cylindrical shape. 7 . The plasma processing apparatus according to claim 6 , further comprising a cylindrical shield member provided on an outer wall of the central gas injection portion.

8. The plasma processing apparatus according to claim 7, wherein: The cylindrical shielding member is formed of a conductive material.

9. The plasma processing apparatus according to claim 1, wherein: A first distance between the outer coil and the dielectric window is different from a second distance between the inner coil and the dielectric window.

10. The plasma processing apparatus according to claim 9, wherein: The first distance is smaller than the second distance.

11. A plasma processing device comprising: a plasma processing chamber; a substrate support disposed in the plasma processing chamber; a dielectric window disposed above the substrate support, the dielectric window having a first central opening; A conductive shielding box having a top and side walls, wherein the top is arranged above the dielectric window, the side walls extend from the dielectric window to the top, the conductive shielding box having an inner space defined by the dielectric window, the top and the side walls, and the top having a second central opening vertically overlapping the first central opening; a central gas injection portion extending vertically through the first central opening of the dielectric window and the second central opening of the conductive shielding box and configured to supply processing gas into the plasma processing chamber, the central gas injection portion being formed of a dielectric material; An antenna is disposed in the inner space of the conductive shielding box in a manner of surrounding the central gas injection portion, and the antenna has: an outer coil having a first open end and a second open end, the outer coil having a first intermediate point and a second intermediate point between the first open end and the second open end, the first intermediate point being connected to a ground potential; and an inner coil disposed between the central gas jet and the outer coil, the inner coil being inductively coupled to the outer coil; and A power source is connected to the second intermediate point of the outer coil.

12. The plasma processing apparatus according to claim 11, wherein: The inner coil includes a variable capacitor.

13. The plasma processing apparatus according to claim 12, wherein: The conductive shielding box is connected to a ground potential.

14. The plasma processing apparatus according to claim 11, wherein: The central gas injection portion has: a lower protrusion protruding downward from the dielectric window, wherein the lower protrusion has a first injection port configured to inject the processing gas downward into the plasma processing chamber and a second injection port configured to inject the processing gas laterally or obliquely into the plasma processing chamber; and An upper protrusion protrudes upward from the top of the conductive shield box, wherein the upper protrusion has a gas introduction port. 15 . The plasma processing apparatus according to claim 14 , further comprising a cylindrical shield member provided on an outer wall of the central gas injection portion.

16. A plasma processing device comprising: a plasma processing chamber; a substrate support disposed in the plasma processing chamber; a dielectric window disposed above the substrate support, the dielectric window having a central opening; a central gas injection portion extending vertically through the central opening of the dielectric window and configured to supply a processing gas into the plasma processing chamber; An antenna is disposed above the dielectric window in a manner surrounding the central gas injection portion, the antenna comprising: an outer coil having a first open end and a second open end, the outer coil having a first intermediate point and a second intermediate point between the first open end and the second open end, the first intermediate point being connected to a ground potential, the first open end being disposed closer to the central gas jet than the second open end, the outer coil having a first radius from a central axis of the central gas jet to the first open end; and an inner coil disposed between the central gas jet and the outer coil, the inner coil being inductively coupled to the outer coil, the inner coil having a second radius from a central axis of the central gas jet to the inner coil, the second radius being smaller than the first radius; and A power source is connected to the second intermediate point of the outer coil.

17. The plasma processing apparatus according to claim 16, wherein: The inner coil includes a variable capacitor.

18. The plasma processing apparatus according to claim 17, wherein: The outer coil is wound in a substantially circular spiral shape for more than two turns.

19. The plasma processing apparatus according to claim 16, wherein: The central gas ejection portion is formed of a dielectric material. 20 . The plasma processing apparatus according to claim 19 , further comprising a cylindrical shield member provided on an outer wall of the central gas injection portion.

Images