Plasma processing apparatus and upper electrode assembly

Abstract

Provided is a technique capable of improving uniformity of gas introduced into a plasma processing space from an upper electrode assembly. This plasma processing apparatus comprises a chamber, a substrate support portion disposed in the chamber, a gas supply portion, and an upper electrode assembly, wherein the upper electrode assembly includes a plurality of annular gas diffusion spaces, at least one gas supply hole configured to supply gas from the gas supply portion to the plurality of annular gas diffusion spaces, a plurality of gas introduction holes configured to introduce gas located in the plurality of annular gas diffusion spaces into the plasma processing space, and a plurality of annular insulating members disposed in each of the plurality of annular gas diffusion spaces, each of the plurality of annular insulating members being configured to face an outlet of the gas supply hole and an inlet of the gas introduction hole in the annular gas diffusion space.

Description

Plasma processing apparatus and upper electrode assembly

[0001] SUMMARY OF THE INVENTION Exemplary embodiments of the present disclosure relate to a plasma processing apparatus and an upper electrode assembly.

[0002] Japanese Patent Application Laid-Open No. 2003-129999 discloses a technique in which a plasma processing apparatus is provided with an upper electrode including a gas flow path.

[0003] Japanese Patent Application Laid-Open No. 2019-192728

[0004] The present disclosure provides a technique that can improve the uniformity of gas introduced into a plasma processing space from an upper electrode assembly.

[0005] In one exemplary embodiment of the present disclosure, a plasma processing apparatus includes a chamber, a substrate support disposed within the chamber, a gas supply unit, and an upper electrode assembly disposed above the substrate support and configured to form a plasma processing space between the upper electrode assembly and the substrate support. The upper electrode assembly includes: a plurality of annular gas diffusion spaces; at least one gas supply hole configured to supply gas from the gas supply unit to the plurality of annular gas diffusion spaces, the at least one gas supply hole having an outlet opening in a ceiling wall surface forming the annular gas diffusion space; a plurality of gas inlet holes configured to introduce gas from the plurality of annular gas diffusion spaces into the plasma processing space, each of the plurality of gas inlet holes having an inlet opening in a bottom wall surface forming the annular gas diffusion space; and a plurality of annular insulating members disposed in each of the plurality of annular gas diffusion spaces, each of the plurality of annular insulating members configured to face the outlet of the gas supply hole and the inlet of the gas inlet hole in the annular gas diffusion space.

[0006] According to one exemplary embodiment of the present disclosure, a technique can be provided that can improve the uniformity of gas introduced into a plasma processing space from an upper electrode assembly.

[0007] FIG. 1 is a diagram for explaining an example of the configuration of a plasma processing system. FIG. 2 is a diagram for explaining an example of the configuration of a plasma processing apparatus. FIG. 3 is a diagram for explaining an example of the configuration of an upper electrode assembly. FIG. 4 is a diagram for explaining an example of the configuration of a lower surface of a cooling plate of an upper electrode assembly. FIG. 5 is a diagram for explaining an example of the configuration of an annular gas diffusion space of an upper electrode assembly. FIG. 6 is a diagram for explaining an example of the configuration of a lower surface of a cooling plate on which an annular insulating member is arranged. FIG. 7 is a diagram for explaining an example of the configuration of a support mechanism. FIG. 8 is a diagram for explaining an example of the configuration of a support mechanism in a state where the disk portion of the locking portion is housed in the first hole portion of the locked portion. FIG. 9 is a diagram for explaining an example of the configuration of a support mechanism in a state where the locking portion and the locked portion are locked.

[0008] Hereinafter, each embodiment of the present disclosure will be described.

[0009] In one exemplary embodiment, a plasma processing apparatus is provided, comprising: a chamber; a substrate support disposed within the chamber; a gas supply unit; and an upper electrode assembly disposed above the substrate support and configured to form a plasma processing space between the upper electrode assembly and the substrate support, wherein the upper electrode assembly includes: a plurality of annular gas diffusion spaces; at least one gas supply hole configured to supply gas from the gas supply unit to the plurality of annular gas diffusion spaces, the at least one gas supply hole having an outlet opening in a ceiling wall surface forming the annular gas diffusion space; a plurality of gas inlet holes configured to introduce gas from the plurality of annular gas diffusion spaces into the plasma processing space, each of the plurality of gas inlet holes having an inlet opening in a bottom wall surface forming the annular gas diffusion space; and a plurality of annular insulating members disposed in each of the plurality of annular gas diffusion spaces, each of the plurality of annular insulating members configured to face the outlet of the gas supply hole and the inlet of the gas inlet hole in the annular gas diffusion space.

[0010] In one exemplary embodiment, the annular insulating member is arranged in the annular gas diffusion space so as to have gaps between it and the top wall surface, bottom wall surface, inner wall surface, and outer wall surface that form the annular gas diffusion space.

[0011] In one exemplary embodiment, the annular insulating member is disposed at the center of the annular gas diffusion space in the vertical and horizontal directions.

[0012] In one exemplary embodiment, the upper electrode assembly further includes a support mechanism configured to support the annular insulating member in the annular gas diffusion space.

[0013] In one exemplary embodiment, the support mechanism is configured to support the annular insulating member by suspending it from a ceiling wall surface that forms the annular gas diffusion space.

[0014] In one exemplary embodiment, the support mechanism has an engaging portion arranged on the ceiling wall surface of the annular gas diffusion space and an engaged portion arranged on the upper surface of the annular insulating member, and is configured so that the engaged portion and the engaging portion are engaged with each other by bringing the upper surface of the annular insulating member close to the ceiling wall surface of the annular gas diffusion space and sliding the annular insulating member circumferentially relative to the ceiling wall surface of the annular gas diffusion space.

[0015] In one exemplary embodiment, the upper electrode assembly includes a showerhead electrode and a cooling plate disposed on the showerhead electrode, wherein at least one gas supply hole is disposed to pass through an interior of the cooling plate, a plurality of annular gas diffusion spaces are disposed between the cooling plate and the showerhead electrode, and a plurality of gas inlet holes are disposed to pass through an interior of the showerhead electrode.

[0016] In one exemplary embodiment, there is provided an upper electrode assembly for use in a plasma processing apparatus, the upper electrode assembly being disposed above a substrate support disposed in a chamber of the plasma processing apparatus and configured to form a plasma processing space between the upper electrode assembly and the substrate support, the upper electrode assembly including: a plurality of annular gas diffusion spaces; at least one gas supply hole configured to supply gas to the plurality of annular gas diffusion spaces, the at least one gas supply hole having an outlet opening in a ceiling wall surface forming the annular gas diffusion space; a plurality of gas inlet holes configured to introduce gas from the plurality of annular gas diffusion spaces into the plasma processing space, each of the plurality of gas inlet holes having an inlet opening in a bottom wall surface forming the annular gas diffusion space; and a plurality of annular insulating members disposed in each of the plurality of annular gas diffusion spaces, each of the plurality of annular insulating members configured to face the outlet of the gas supply hole and the inlet of the gas inlet hole in the annular gas diffusion space.

[0017] In one exemplary embodiment, the annular insulating member is arranged in the annular gas diffusion space so as to have gaps between it and the top wall surface, bottom wall surface, inner wall surface, and outer wall surface that form the annular gas diffusion space.

[0018] In one exemplary embodiment, the annular insulating member is disposed at the center of the annular gas diffusion space in the vertical and horizontal directions.

[0019] In one exemplary embodiment, the annular insulating member further comprises a support mechanism configured to support the annular insulating member in the annular gas diffusion space.

[0020] In one exemplary embodiment, the support mechanism is configured to support the annular insulating member by suspending it from a ceiling wall surface that forms the annular gas diffusion space.

[0021] In one exemplary embodiment, the support mechanism has an engaging portion arranged on the ceiling wall surface of the annular gas diffusion space and an engaged portion arranged on the upper surface of the annular insulating member, and is configured so that the engaged portion and the engaging portion are engaged with each other by bringing the upper surface of the annular insulating member close to the ceiling wall surface of the annular gas diffusion space and sliding the annular insulating member circumferentially relative to the ceiling wall surface of the annular gas diffusion space.

[0022] In one exemplary embodiment, the plasma processing apparatus further includes a showerhead electrode and a cooling plate disposed on the showerhead electrode, wherein the at least one gas supply hole is disposed to pass through an interior of the cooling plate, the plurality of annular gas diffusion spaces are disposed between the cooling plate and the showerhead electrode, and the plurality of gas introduction holes are disposed to pass through an interior of the showerhead electrode.

[0023] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are designated by the same reference numerals, and redundant explanations will be omitted. Unless otherwise specified, the positional relationships, such as up, down, left, and right, will be described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0024] <Example of Plasma Processing System> FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0025] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like. Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include radio frequency (RF) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0026] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 may be implemented by, for example, a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. This program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0027] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0028] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10 (also simply referred to as the "chamber"), a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0029] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0030] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal, which will be described later, is supplied to the at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple lower electrodes. Furthermore, the electrostatic electrode 1111b may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0031] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0032] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside of the substrate W and the central region 111a.

[0033] The showerhead 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas inlet may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0034] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0035] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. This generates a plasma from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, thereby attracting ion components in the formed plasma to the substrate W.

[0036] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0037] The second RF generator 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0038] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to the at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to the at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0039] In various embodiments, the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof pulse waveform. In one embodiment, a waveform generator for generating the sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. When the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulses may have either positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one period. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b.

[0040] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0041] In one embodiment, the showerhead 13 includes an upper electrode assembly 200. FIG. 3 is a diagram illustrating an example of the configuration of the upper electrode assembly 200. The upper electrode assembly 200 is disposed above the substrate support 11. The upper electrode assembly 200 is configured to form a plasma processing space 10s between the upper electrode assembly 200 and the substrate support 11. The upper electrode assembly 200 is electrically connected to the power supply 30. The upper electrode assembly 200 may be supported on the sidewall 10a of the chamber 10 via an annular insulator 201. The annular insulator 201 may be a part of the upper electrode assembly 200.

[0042] In one embodiment, the upper electrode assembly 200 includes a showerhead electrode (top plate) 210 and a cooling plate (support) 211 disposed on the showerhead electrode 210 .

[0043] In one embodiment, the showerhead electrode 210 has a substantially circular plate shape. The showerhead electrode 210 is made of a conductive material or an insulating material. The showerhead electrode 210 is configured to be detachable from the cooling plate 211.

[0044] In one embodiment, the cooling plate 211 has a coolant flow path 220 therein. The coolant flow path 220 is connected to a chiller unit 230 disposed outside the upper electrode assembly 200. The cooling plate 211 is configured to be cooled by supplying a coolant from the chiller unit 230 to the coolant flow path 220 and circulating the coolant. The cooling plate 211 has a substantially circular plate shape. The cooling plate 211 is formed of a conductive material.

[0045] The upper electrode assembly 200 is configured to introduce gas supplied from the gas supply unit 20 into the plasma processing space 10s. In one embodiment, the upper electrode assembly 200 has a plurality of annular gas diffusion spaces 300, at least one gas supply hole 301, a plurality of gas introduction holes 302, and a plurality of annular insulating members 303. The annular gas diffusion space 300 may be an example of the gas diffusion chamber 13b shown in FIG. 2 , the gas supply hole 301 may be an example of the gas supply port 13a, and the gas introduction hole 302 may be an example of the gas introduction port 13c.

[0046] As shown in Fig. 3, the plurality of annular gas diffusion spaces 300 are spaces formed inside the upper electrode assembly 200. In one embodiment, as shown in Figs. 3 and 4, the plurality of annular gas diffusion spaces 300 are concentrically arranged horizontally outward from the center of the upper electrode assembly 200. Note that Fig. 4 is a diagram illustrating an example of the underside of the cooling plate 221 from which the showerhead electrode 210 has been removed to expose the plurality of annular gas diffusion spaces 300.

[0047] As shown in FIG. 3 , multiple annular gas diffusion spaces 300 are disposed between the showerhead electrode 210 and the cooling plate 211. In one embodiment, the cooling plate 211 has multiple annular recesses 330 on its lower surface, and the openings (lower surfaces) of the annular recesses 330 are closed by the upper surface 210 a of the showerhead electrode 210. The annular gas diffusion spaces 300 are defined by the annular recesses 330 and the upper surface 210 a. That is, as shown in FIG. 5 , the annular recesses 330 of the cooling plate 211 define the ceiling wall surface 300 a, inner wall surface 300 b, and outer wall surface 300 c of the annular gas diffusion space 300, and the upper surface 210 a of the showerhead electrode 210 defines the bottom wall surface 300 d of the annular gas diffusion space 300. In one embodiment, the annular gas diffusion space 300 has a rectangular shape in a cross section perpendicular to the circumferential direction of the annular gas diffusion space 300.

[0048] As shown in Fig. 3, the gas supply hole 301 is connected to the gas supply unit 20. The gas supply hole 301 is configured to supply gas from the gas supply unit 20 to the multiple annular gas diffusion spaces 300. The gas supply hole 301 is connected from the upper surface of the cooling plate 211 through the interior of the cooling plate 211 to the multiple annular gas diffusion spaces 300 on the lower surface of the cooling plate 211. The gas supply hole 301 has multiple outlets 340 that open to the ceiling wall surface 300a of each of the multiple annular gas diffusion spaces 300. As shown in Fig. 4, the multiple outlets 340 are arranged at equal intervals in the circumferential direction on the ceiling wall surface 300a of each of the multiple annular gas diffusion spaces 300.

[0049] 3 , the gas introduction holes 302 are configured to introduce gas from the annular gas diffusion spaces 300 into the plasma processing space 10s. The gas introduction holes 302 are arranged to vertically penetrate the interior of the showerhead electrode 210. The gas introduction holes 302 have a plurality of inlets 350 opening in the bottom wall surface 300d of each of the annular gas diffusion spaces 300. The inlets 350 are arranged circumferentially and radially on the bottom wall surface 300d of each of the annular gas diffusion spaces 300. The number of inlets 350 in each of the annular gas diffusion spaces 300 may be greater than the number of outlets 340.

[0050] A plurality of annular insulating members 303 are disposed in each of the plurality of annular gas diffusion spaces 300. In one embodiment, the annular insulating members 303 have a shape similar to but smaller than the annular gas diffusion spaces 300. As shown in FIG. 6 , the annular insulating members 303 have an annular plate shape. The annular insulating members 303 may be formed of quartz, ceramics, or the like. As shown in FIG. 5 , the annular insulating members 303 are configured in the annular gas diffusion spaces 300 to face the outlets 340 of the gas supply holes 301 and the inlets 350 of the gas introduction holes 302. The annular insulating members 303 are disposed so as to vertically overlap the outlets 340 of the gas supply holes 301 and the inlets 350 of the gas introduction holes 302 and cover the outlets 340 and the inlets 350.

[0051] The annular insulating member 303 has a first gap between itself and the ceiling wall surface 300a of the annular gas diffusion space 300, a second gap between itself and the bottom wall surface 300d, a third gap between itself and the inner wall surface 300b, and a fourth gap between itself and the outer wall surface 300c. In one embodiment, the annular insulating member 303 is disposed at the center of the annular gas diffusion space 300 in the vertical and horizontal directions (horizontal direction). That is, the first gap between the upper surface 303a of the annular insulating member 303 and the ceiling wall surface 300a, the second gap between the lower surface 303d of the annular insulating member 303 and the bottom wall surface 300d, the third gap between the inner surface 303b of the annular insulating member 303 and the inner wall surface 300b, and the fourth gap between the outer surface 303c of the annular insulating member 303 and the outer wall surface 300c may have the same distance.

[0052] In one embodiment, the upper electrode assembly 200 includes a support mechanism 400 configured to support the annular insulating member 303 in the annular gas diffusion space 300 .

[0053] As shown in FIG. 7 , the support mechanism 400 may be configured to support the annular insulating member 303 by suspending it from the ceiling wall surface 300 b of the annular gas diffusion space 300 .

[0054] In one embodiment, the support mechanism 400 has a locking portion 410 arranged on the ceiling wall surface 300 a of the annular gas diffusion space 300 , and a locked portion 411 arranged on the upper surface 303 a of the annular insulating member 303 .

[0055] In one embodiment, the locking portion 410 has a support portion 420 extending downward from the ceiling wall surface 300a, and a disk portion 421 disposed at the bottom of the support portion 420. A screw is formed at the top of the support portion 420, and the support portion 420 is screwed to the ceiling wall surface 300a. The disk portion 421 is attached to the bottom of the support portion 420 so that its central axis coincides with that of the support portion 420. The disk portion 421 has a larger diameter than the support portion 420.

[0056] In one embodiment, the locked portion 411 has a first hole 430 and a second hole 431 formed in the upper surface 303a of the annular insulating member 303. The first hole 430 and the second hole 431 are adjacent to each other in the circumferential direction of the annular insulating member 303 and are connected to each other. In one embodiment, the first hole 430 and the second hole 431 have an arc shape extending in the circumferential direction of the annular insulating member 303 and are configured to be able to accommodate the disk portion 421 of the locking portion 410. Furthermore, the first hole 430 and the second hole 431 are configured so that the accommodated disk portion 421 can move circumferentially within the first hole 430 and the second hole 431.

[0057] The second hole portion 431 has a top plate 431a that forms an opening OP2. The opening OP2 of the second hole portion 431 is continuous with the opening OP1 of the first hole portion 430. The diameter of the opening OP2 of the second hole portion 431 is smaller than the diameter of the opening OP1 of the first hole portion 430. The diameter of the opening OP1 of the first hole portion 430 is larger than the diameter of the disc portion 421 of the locking portion 410, and the diameter of the opening OP2 of the second hole portion 431 is smaller than the diameter of the disc portion 421 and larger than the diameter of the support portion 420. The openings OP1 and OP2 are configured to allow the support portion 420 to move back and forth.

[0058] As shown in Fig. 8 , the upper surface 303a of the annular insulating member 303 is brought close to the ceiling wall surface 300a of the annular gas diffusion space 300, and the disk portion 421 of the ceiling wall surface 300a is inserted into the first hole portion 430 of the upper surface 303a of the annular insulating member 303. Then, as shown in Fig. 9 , the annular insulating member 303 is slid in the positive circumferential direction relative to the ceiling wall surface 300a of the annular gas diffusion space 300, and the disk portion 421 is slid from the first hole portion 430 to the second hole portion 431. In this manner, the top plate 431a of the second hole portion 431 is supported by the disk portion 421, and the locked portion 411 and the locking portion 410 are locked. In this manner, the annular insulating member 303 can be attached to the ceiling wall surface 300a. On the other hand, by sliding the annular insulating member 303 in the opposite circumferential direction relative to the ceiling wall surface 300a and sliding the disc portion 421 from the second hole portion 431 to the first hole portion 430, the engagement between the engaged portion 411 and the engaging portion 410 can be released, and the annular insulating member 303 can be removed from the ceiling wall surface 300a.

[0059] <Example of Plasma Processing> Plasma processing is performed in the plasma processing apparatus 1. The plasma processing includes an etching process in which a film on a substrate W is etched using plasma. In one embodiment, the plasma processing is performed by the control unit 2 in the plasma processing apparatus 1.

[0060] In the plasma processing apparatus 1 shown in FIG. 2, first, the substrate W is carried into the chamber 10 by a transport arm, placed on the substrate support portion 11 by a lifter, and held on the substrate support portion 11 by suction.

[0061] Next, plasma is generated in the plasma processing space 10s by the plasma generating unit. First, the atmosphere in the plasma processing space 10s is exhausted through the gas exhaust port 10e, and the inside of the plasma processing space 10s is depressurized. In one embodiment, in the upper electrode assembly 250 shown in FIG. 3, a process gas is supplied from the gas supply unit 20 to the upper electrode assembly 200 and introduced from the upper electrode assembly 200 into the plasma processing space 10s. As shown in FIG. 5, the process gas is supplied to each of the annular gas diffusion spaces 300 through the gas supply holes 301. The process gas flowing out from the outlet 340 of the gas supply hole 301 hits the upper surface 303a of the annular insulating member 303 and diffuses left and right along the upper surface 303a. At this time, the process gas passes through a first gap between the upper surface 303a and the ceiling wall surface 300a. The process gas then descends through a second gap between the inner surface 303b of the annular insulating member 303 and the inner wall surface 300b of the annular gas diffusion space 300, and a third gap between the outer surface 303c of the annular insulating member 303 and the outer wall surface 300c of the annular gas diffusion space 300. The process gas then passes through a fourth gap between the lower surface 303d of the annular insulating member 303 and the bottom wall surface 300d of the annular gas diffusion space 300, and flows into the inlets 350 of the multiple gas introduction holes 302. The process gas that has flowed into the inlets 350 of the gas introduction holes 302 descends through the gas introduction holes 302 and is introduced into the plasma processing space 10s. The process gas introduced into the plasma processing space 10s at this time includes a gas that generates active species necessary for etching the substrate W.

[0062] A source RF signal is supplied from the power supply 30 to the upper electrode and / or the upper electrode assembly 200. A bias RF signal or a bias DC signal is supplied to the lower electrode. A plasma is generated from the processing gas on the substrate support 11 in the plasma processing space 10s, and the substrate W is etched.

[0063] According to this exemplary embodiment, the plasma processing apparatus 1 includes a chamber 10, a substrate support 11, a gas supply unit 20, and an upper electrode assembly 200. The upper electrode assembly 200 includes a plurality of annular gas diffusion spaces 300, at least one gas supply hole 301 configured to supply gas from the gas supply unit to the plurality of annular gas diffusion spaces 300, a plurality of gas inlet holes 302 configured to introduce gas from the plurality of annular gas diffusion spaces 300 into a plasma processing space 10s, and a plurality of annular insulating members 303 disposed in each of the plurality of annular gas diffusion spaces 300. Each of the plurality of annular insulating members 303 is configured to face an outlet 340 of the gas supply hole 301 and an inlet 350 of the gas inlet hole 302 in the annular gas diffusion space 300. This uniformizes the pressure of the gas passing through the plurality of gas inlet holes 302, thereby improving the uniformity of the gas introduced from the upper electrode assembly into the plasma processing space 10s. In addition, gas is prevented from stagnation in the annular gas diffusion space 300, and products generated from the gas are prevented from accumulating on the wall surfaces of the annular gas diffusion space 300. Furthermore, by disposing the annular insulating member 303 in the annular gas diffusion space 300, abnormal discharge is prevented from occurring in the annular gas diffusion space 300. Furthermore, by making the flow rates of gas flowing through the plurality of gas introduction holes 302 uniform, the maximum flow rate of gas through the plurality of gas introduction holes 302 is reduced, and as a result, discharge is prevented from occurring in the gas introduction holes 302.

[0064] In this exemplary embodiment, the annular insulating member 303 is arranged in the annular gas diffusion space 300 so as to have gaps between the top wall surface 300 a, the bottom wall surface 300 d, the inner wall surface 300 b, and the outer wall surface 300 c. This prevents gas from stagnation in the annular gas diffusion space 300 and prevents products generated from the gas from accumulating on the wall surfaces of the annular gas diffusion space 300.

[0065] In this exemplary embodiment, the annular insulating member 303 is disposed at the center in the vertical and horizontal directions of the annular gas diffusion space 300. This prevents gas from stagnation in the annular gas diffusion space 300 and prevents products generated from the gas from accumulating on the wall surfaces of the annular gas diffusion space 300.

[0066] In this exemplary embodiment, the upper electrode assembly 200 further includes a support mechanism 400 configured to support the annular insulating member 303 in the annular gas diffusion space 300. This allows the annular insulating member 303 to be supported in the annular gas diffusion space 300.

[0067] In this exemplary embodiment, the support mechanism 400 is configured to support the annular insulating member 303 by suspending it from the ceiling wall surface 300a that forms the annular gas diffusion space 300. This prevents the support mechanism 400 from being exposed to plasma in the plasma processing space 10s, thereby preventing contamination of the support mechanism 400 by plasma.

[0068] In this exemplary embodiment, the support mechanism 400 has an engaging portion 410 on the ceiling wall surface 300a and an engaged portion 411 on the upper surface 303a of the annular insulating member 303, and is configured so that the engaged portion 411 and the engaging portion 410 are engaged with each other by bringing the upper surface 303a of the annular insulating member 303 close to the ceiling wall surface 300a of the annular gas diffusion space 300 and sliding the annular insulating member 303 circumferentially relative to the ceiling wall surface 300a. This allows the annular insulating member 303 to be supported in the annular gas diffusion space 300. The annular insulating member 303 can be attached to and detached from the cooling plate 211.

[0069] In the above embodiment, the support mechanism 400 supports the annular insulating member 303 so as to suspend it, but the annular insulating member 303 may be supported from below or from the side. For example, a support portion for supporting the annular insulating member 303 may be disposed on the bottom wall surface 300d of the annular gas diffusion space 300. Support portions for supporting the annular insulating member 303 may be disposed on the inner wall surface 300b and the outer wall surface 300c of the annular gas diffusion space 300.

[0070] In the above embodiment, the upper electrode assembly 200 has the showerhead electrode 210 and the cooling plate 211 as described above, but the configuration of the upper electrode assembly 200 is not limited to this. That is, the upper electrode assembly may have other configurations as long as it is disposed above a substrate support disposed in a chamber of a plasma processing apparatus, configured to form a plasma processing space between itself and the substrate support, and includes a plurality of annular gas diffusion spaces, at least one gas supply hole configured to supply gas to the plurality of annular gas diffusion spaces, a plurality of gas inlet holes configured to introduce gas from the plurality of annular gas diffusion spaces into the plasma processing space, and a plurality of annular insulating members disposed in each of the plurality of annular gas diffusion spaces, each of the plurality of annular insulating members configured to face an outlet of the gas supply hole and an inlet of the gas inlet hole in the annular gas diffusion space.

[0071] Embodiments of the present disclosure further include the following aspects.

[0072] a substrate support disposed within the chamber; a gas supply unit; and an upper electrode assembly disposed above the substrate support and configured to form a plasma processing space between the upper electrode assembly and the substrate support, wherein the upper electrode assembly includes: a plurality of annular gas diffusion spaces; at least one gas supply hole configured to supply gas from the gas supply unit to the plurality of annular gas diffusion spaces, the at least one gas supply hole having an outlet opening in a ceiling wall surface forming the annular gas diffusion space; a plurality of gas introduction holes configured to introduce gas from the plurality of annular gas diffusion spaces into the plasma processing space, each of the plurality of gas introduction holes having an inlet opening in a bottom wall surface forming the annular gas diffusion space; and a plurality of annular insulating members disposed in each of the plurality of annular gas diffusion spaces, each of the plurality of insulating members configured to face the outlet of the gas supply hole and the inlet of the gas introduction hole in the annular gas diffusion space.

[0073] (Supplementary Note 2) The plasma processing apparatus according to Supplementary Note 1, wherein the annular insulating member is arranged in the annular gas diffusion space so as to have a gap between the annular insulating member and the ceiling wall surface, the bottom wall surface, the inner wall surface, and the outer wall surface that form the annular gas diffusion space.

[0074] (Supplementary Note 3) The plasma processing apparatus according to Supplementary Note 2, wherein the annular insulating member is disposed at the center of the annular gas diffusion space in the vertical and horizontal directions.

[0075] (Supplementary Note 4) The plasma processing apparatus according to any one of Supplementary Notes 1 to 3, wherein the upper electrode assembly further includes a support mechanism configured to support the annular insulating member in the annular gas diffusion space.

[0076] (Supplementary Note 5) The plasma processing apparatus according to Supplementary Note 4, wherein the support mechanism is configured to support the annular insulating member by suspending it from the ceiling wall surface that forms the annular gas diffusion space.

[0077] (Appendix 6) The plasma processing apparatus described in Appendix 5, wherein the support mechanism has an engaging portion arranged on the ceiling wall surface of the annular gas diffusion space and an engaged portion arranged on the upper surface of the annular insulating member, and is configured so that the engaged portion and the engaging portion are engaged with each other by bringing the upper surface of the annular insulating member close to the ceiling wall surface of the annular gas diffusion space and sliding the annular insulating member circumferentially relative to the ceiling wall surface of the annular gas diffusion space.

[0078] (Supplementary Note 7) The plasma processing apparatus according to any one of Supplementary Notes 1 to 6, wherein the upper electrode assembly includes: a shower head electrode; and a cooling plate disposed on the shower head electrode; the at least one gas supply hole is disposed to pass through an interior of the cooling plate; the plurality of annular gas diffusion spaces are disposed between the cooling plate and the shower head electrode; and the plurality of gas introduction holes are disposed to pass through an interior of the shower head electrode.

[0079] (Supplementary Note 8) An upper electrode assembly for use in a plasma processing apparatus, the upper electrode assembly being disposed above a substrate support disposed in a chamber of the plasma processing apparatus and configured to form a plasma processing space between the upper electrode assembly and the substrate support, the upper electrode assembly including: a plurality of annular gas diffusion spaces; at least one gas supply hole configured to supply a gas to the plurality of annular gas diffusion spaces, the at least one gas supply hole having an outlet opening in a ceiling wall surface forming the annular gas diffusion spaces; a plurality of gas introduction holes configured to introduce gas from the plurality of annular gas diffusion spaces into the plasma processing space, each of the plurality of gas introduction holes having an inlet opening in a bottom wall surface forming the annular gas diffusion space; and a plurality of annular insulating members disposed in each of the plurality of annular gas diffusion spaces, each of the plurality of insulating members configured to face the outlet of the gas supply hole and the inlet of the gas introduction hole in the annular gas diffusion space.

[0080] (Supplementary Note 9) The upper electrode assembly according to Supplementary Note 8, wherein the annular insulating member is arranged in the annular gas diffusion space so as to have gaps between the annular insulating member and the ceiling wall surface, the bottom wall surface, the inner wall surface, and the outer wall surface that form the annular gas diffusion space.

[0081] (Supplementary Note 10) The upper electrode assembly according to Supplementary Note 9, wherein the annular insulating member is disposed at the center of the annular gas diffusion space in the vertical and horizontal directions.

[0082] (Supplementary Note 11) The upper electrode assembly according to any one of Supplementary Notes 8 to 10, further comprising a support mechanism configured to support the annular insulating member in the annular gas diffusion space.

[0083] (Supplementary Note 12) The upper electrode assembly according to Supplementary Note 11, wherein the support mechanism is configured to support the annular insulating member by suspending it from the ceiling wall surface that forms the annular gas diffusion space.

[0084] (Appendix 13) The upper electrode assembly described in Appendix 12, wherein the support mechanism has an engaging portion arranged on the ceiling wall surface of the annular gas diffusion space and an engaged portion arranged on the upper surface of the annular insulating member, and is configured so that the engaged portion and the engaging portion are engaged with each other by bringing the upper surface of the annular insulating member close to the ceiling wall surface of the annular gas diffusion space and sliding the annular insulating member circumferentially relative to the ceiling wall surface of the annular gas diffusion space.

[0085] (Supplementary Note 14) The upper electrode assembly according to any one of Supplementary Notes 8 to 13, further comprising: a showerhead electrode; and a cooling plate disposed on the showerhead electrode, wherein the at least one gas supply hole is disposed to pass through an interior of the cooling plate; the plurality of annular gas diffusion spaces are disposed between the cooling plate and the showerhead electrode; and the plurality of gas introduction holes are disposed to pass through an interior of the showerhead electrode.

[0086] The above embodiments are described for the purpose of explanation and are not intended to limit the scope of the present disclosure. Various modifications can be made to the above embodiments without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment can be added to other embodiments. Also, some components in one embodiment can be replaced with corresponding components in other embodiments.

[0087] 1: Plasma processing apparatus, 10: Chamber, 10s: Plasma processing space, 11: Substrate support, 20: Gas supply unit, 200: Upper electrode assembly, 210: Shower head electrode, 211: Cooling plate, 300: Annular gas diffusion space, 301: Gas supply hole, 302: Gas introduction hole, 303: Annular insulating member, 400: Support mechanism, W: Substrate

Claims

1. A plasma processing apparatus comprising: a chamber; a substrate support disposed within the chamber; a gas supply unit; and an upper electrode assembly disposed above the substrate support and configured to form a plasma processing space between the upper electrode assembly and the substrate support, wherein the upper electrode assembly includes: a plurality of annular gas diffusion spaces; at least one gas supply hole configured to supply gas from the gas supply unit to the plurality of annular gas diffusion spaces, the at least one gas supply hole having an outlet opening in a ceiling wall surface forming the annular gas diffusion space; a plurality of gas inlet holes configured to introduce gas from the plurality of annular gas diffusion spaces into the plasma processing space, each of the plurality of gas inlet holes having an inlet opening in a bottom wall surface forming the annular gas diffusion space; and a plurality of annular insulating members disposed in each of the plurality of annular gas diffusion spaces, each of the plurality of annular insulating members configured to face the outlet of the gas supply hole and the inlet of the gas inlet hole in the annular gas diffusion space.

2. The plasma processing apparatus according to claim 1, wherein the annular insulating member is arranged in the annular gas diffusion space so as to have a gap between the annular insulating member and the ceiling wall surface, the bottom wall surface, the inner wall surface, and the outer wall surface that form the annular gas diffusion space.

3. The plasma processing apparatus according to claim 2, wherein the annular insulating member is disposed at the center of the annular gas diffusion space in the vertical and horizontal directions.

4. The plasma processing apparatus according to claim 1, wherein the upper electrode assembly further includes a support mechanism configured to support the annular insulating member in the annular gas diffusion space.

5. The plasma processing apparatus according to claim 4, wherein the support mechanism is configured to support the annular insulating member by suspending it from the ceiling wall surface that forms the annular gas diffusion space.

6. The plasma processing apparatus described in claim 5, wherein the support mechanism has an engaging portion arranged on the ceiling wall surface of the annular gas diffusion space and an engaged portion arranged on the upper surface of the annular insulating member, and is configured so that the engaged portion and the engaging portion are engaged with each other by bringing the upper surface of the annular insulating member close to the ceiling wall surface of the annular gas diffusion space and sliding the annular insulating member circumferentially relative to the ceiling wall surface of the annular gas diffusion space.

7. The plasma processing apparatus of claim 1, wherein the upper electrode assembly comprises: a showerhead electrode; and a cooling plate disposed on the showerhead electrode; the at least one gas supply hole is disposed so as to pass through an interior of the cooling plate; the plurality of annular gas diffusion spaces are disposed between the cooling plate and the showerhead electrode; and the plurality of gas introduction holes are disposed so as to pass through an interior of the showerhead electrode.

8. An upper electrode assembly for use in a plasma processing apparatus, the upper electrode assembly being disposed above a substrate support disposed in a chamber of the plasma processing apparatus and configured to form a plasma processing space between the upper electrode assembly and the substrate support, the upper electrode assembly including: a plurality of annular gas diffusion spaces; at least one gas supply hole configured to supply gas to the plurality of annular gas diffusion spaces, the at least one gas supply hole having an outlet opening in a ceiling wall surface forming the annular gas diffusion spaces; a plurality of gas introduction holes configured to introduce gas from the plurality of annular gas diffusion spaces into the plasma processing space, each of the plurality of gas introduction holes having an inlet opening in a bottom wall surface forming the annular gas diffusion space; and a plurality of annular insulating members disposed in each of the plurality of annular gas diffusion spaces, each of the plurality of annular insulating members configured to face the outlet of the gas supply hole and the inlet of the gas introduction hole in the annular gas diffusion space.

9. The upper electrode assembly according to claim 8, wherein the annular insulating member is arranged in the annular gas diffusion space so as to have gaps between the annular insulating member and the top wall surface, the bottom wall surface, the inner wall surface, and the outer wall surface that form the annular gas diffusion space.

10. The upper electrode assembly according to claim 9, wherein the annular insulating member is disposed at the center of the annular gas diffusion space in the vertical and horizontal directions.

11. The upper electrode assembly of claim 8, further comprising a support mechanism configured to support the annular insulating member in the annular gas diffusion space.

12. The upper electrode assembly according to claim 11, wherein the support mechanism is configured to support the annular insulating member by suspending it from the ceiling wall surface that defines the annular gas diffusion space.

13. An upper electrode assembly as described in claim 12, wherein the support mechanism has an engaging portion arranged on the ceiling wall surface of the annular gas diffusion space and an engaged portion arranged on the upper surface of the annular insulating member, and is configured so that the engaged portion and the engaging portion are engaged with each other by bringing the upper surface of the annular insulating member close to the ceiling wall surface of the annular gas diffusion space and sliding the annular insulating member circumferentially relative to the ceiling wall surface of the annular gas diffusion space.

14. The upper electrode assembly of claim 8, further comprising: a showerhead electrode; and a cooling plate disposed on the showerhead electrode, wherein the at least one gas supply hole is disposed to pass through an interior of the cooling plate; the plurality of annular gas diffusion spaces are disposed between the cooling plate and the showerhead electrode; and the plurality of gas introduction holes are disposed to pass through an interior of the showerhead electrode.

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