Upper electrode and plasma processing apparatus

Abstract

To provide technique for suppressing an abnormal discharge in an upper electrode.SOLUTION: An upper electrode disclosed, constructs a shower head in a capacity coupling type plasma processing apparatus. The upper electrode comprises: a first member; a second member; and a third member. The first member is formed by a conductor. The first member provides a first gas hole. The first gas hole penetrates the first member. The second member is formed by a conductor. The second member is provided on the first member. The second member provides a second gas hole. The third member is formed by a dielectric body. The third member is provided between the first member and the second member. The third member defines a gas diffusion chamber. The first gas hole and the second gas hole are connected to the gas diffusion chamber.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to an upper electrode and a plasma processing apparatus.

Background Art

[0002] In plasma processing of a substrate, a plasma processing apparatus is used. One type of plasma processing apparatus is a capacitively coupled plasma processing apparatus, which includes a plasma processing chamber, a substrate support, and an upper electrode. The upper electrode is provided above the substrate support and constitutes a shower head. Inside the upper electrode, a gas diffusion chamber into which a processing gas is introduced from a gas inlet is defined.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for suppressing abnormal discharge in an upper electrode.

Means for Solving the Problems

[0005] In one exemplary embodiment, an upper electrode is provided. The upper electrode constitutes a shower head in a capacitively coupled plasma processing apparatus. The upper electrode includes a first member, a second member, and a third member. The first member is formed of a conductor. The first member provides a plurality of first gas holes. The plurality of first gas holes penetrate the first member. The second member is formed of a conductor. The second member is provided on the first member. The second member provides one or more second gas holes. The third member is formed of a dielectric. The third member is provided between the first member and the second member. The third member defines a gas diffusion chamber. The gas diffusion chamber is connected to the plurality of first gas holes and the one or more second gas holes.

Effect of the Invention

[0006] According to one exemplary embodiment, abnormal discharge at the upper electrode is suppressed.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Best Mode for Carrying Out the Invention

[0008] Hereinafter, various exemplary embodiments will be described.

[0009] In one exemplary embodiment, an upper electrode is provided. The upper electrode constitutes a shower head in a capacitively coupled plasma processing apparatus. The upper electrode includes a first member, a second member, and a third member. The first member is formed of a conductor. The first member provides a plurality of first gas holes. The plurality of first gas holes penetrate the first member. The second member is formed of a conductor. The second member is provided on the first member. The second member provides one or more second gas holes. The third member is formed of a dielectric. The third member is provided between the first member and the second member. The third member defines a gas diffusion chamber. The plurality of first gas holes and one or more second gas holes are connected to the gas diffusion chamber.

[0010] In the above embodiment, the gas diffusion chamber is defined by a third member formed of a dielectric. Therefore, even if electrons or positive ions enter the gas diffusion chamber from each of the plurality of first gas holes and collide with the third member that defines the gas diffusion chamber, the amount of secondary electrons emitted from the third member is small. As a result, abnormal discharge at the upper electrode is suppressed.

[0011] In one exemplary embodiment, the upper electrode may further include at least one of a first seal member and a second seal member. The first seal member is sandwiched between the first member and the third member. The second seal member is sandwiched between the second member and the third member. The first seal member suppresses the formation of a flow of processing gas toward the gap between the first member and the third member. The second seal member suppresses the formation of a flow of processing gas toward the gap between the second member and the third member. The flow of processing gas formed in the gas diffusion chamber is stabilized by at least one of the first seal member and the second seal member.

[0012] In one exemplary embodiment, the third member may include a side wall and a top portion. The side wall extends circumferentially so as to surround the gas diffusion chamber. The top portion extends over the gas diffusion chamber. The second seal member may be sandwiched between the side wall of the third member and the second member. Alternatively, the second seal member may be sandwiched between the top portion of the third member and the second member. By being sandwiched between the second member and the third member, the second seal member exerts a reaction force on the third member. Due to this reaction force, the relative position of the third member with respect to the first member is fixed. Accordingly, the friction between the third member and the first member is suppressed. As a result, the generation of particles due to the friction between the third member and the first member is suppressed.

[0013] In one exemplary embodiment, the top portion may be arranged so as to face the opening end on the gas diffusion chamber side of each of the plurality of first gas holes. Since the opening end of each of the plurality of first gas holes faces the top portion, many of the electrons or positive ions that have entered the gas diffusion chamber from each of the plurality of first gas holes tend to collide with the top portion. It is difficult for secondary electrons to be emitted from the top portion. Accordingly, according to this embodiment, abnormal discharge at the upper electrode is further suppressed.

[0014] In one exemplary embodiment, the third member may include a bottom portion. The bottom portion may be disposed below the gas diffusion chamber.

[0015] In one exemplary embodiment, the bottom portion may provide a plurality of third gas holes. The plurality of third gas holes may be aligned with the plurality of first gas holes respectively. The electrons or positive ions that have entered the plurality of first gas holes may collide with the wall surface defining the plurality of third gas holes before reaching the gas diffusion chamber. The wall surface defining the plurality of third gas holes is difficult to emit secondary electrons. Accordingly, according to this embodiment, abnormal discharge at the upper electrode is further suppressed.

[0016] In one exemplary embodiment, the second seal member may be sandwiched between the second member and the bottom. By being sandwiched between the second member and the bottom, the second seal member exerts a reaction force on the third member. Due to this reaction force, the relative position of the third member with respect to the first member is fixed. Therefore, the friction between the third member and the first member is suppressed. As a result, the generation of particles due to the friction between the third member and the first member is suppressed.

[0017] In one exemplary embodiment, the first seal member may be sandwiched between the first member and the bottom. In this embodiment, particles that may be generated due to the friction between the third member and the first member are suppressed from entering the plurality of first gas holes.

[0018] In one exemplary embodiment, at least one of the first seal member and the second seal member may separate the boundary between the first member and the second member from the gas diffusion chamber. In this embodiment, the boundary where abnormal discharge is likely to occur is separated from the gas diffusion chamber by at least one of the first seal member or the second seal member. Therefore, abnormal discharge at the upper electrode is further suppressed.

[0019] In one exemplary embodiment, at least one of the first seal member and the second seal member may separate the boundary between the first member and the second member from the plurality of third gas holes. Particles that may be generated due to the friction between the third member and the second member from entering the plurality of third gas holes are suppressed by at least one of the first seal member and the second seal member.

[0020] In one exemplary embodiment, the third member may separate the boundary between the first member and the second member from the gas diffusion chamber. In this embodiment, the boundary B where abnormal discharge is likely to occur is separated from the gas diffusion chamber by the third member. Therefore, abnormal discharge at the upper electrode is further suppressed.

[0021] In one exemplary embodiment, the third member may have a contact portion. The contact portion may be in contact with the first member. The contact portion may be formed of a low-friction member. The low-friction member may have a lower coefficient of friction than portions of the third member other than the contact portion. The first member contacts the contact portion. Accordingly, the frictional resistance between the first member and the third member is reduced. As a result, the generation of particles due to friction between the first member and the third member is suppressed.

[0022] In one exemplary embodiment, the dielectric may be a porous body.

[0023] In one exemplary embodiment, the first sealing member may be an O-ring. The first sealing member may be a gasket. The second sealing member may be an O-ring. The second sealing member may be a gasket.

[0024] In another exemplary embodiment, the plasma processing apparatus includes a plasma processing chamber, a substrate support portion, and an upper electrode. The plasma processing chamber provides a processing space therein. The substrate support portion is provided in the plasma processing chamber. The upper electrode is any of the various upper electrodes of the above-described exemplary embodiments and is provided above the substrate support portion.

[0025] Hereinafter, a configuration example of a plasma processing system will be described. FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0026] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a control unit 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a showerhead 13. The substrate support unit 11 is disposed in the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support unit 11. In one embodiment, the showerhead 13 constitutes at least a part 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, the side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas discharge port for discharging gas from the plasma processing space. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support unit 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0027] The substrate support unit 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the 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. Accordingly, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as a ring support surface for supporting the ring assembly 112.

[0028] 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 other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. 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. Also, at least one RF / DC electrode coupled to an RF (Radio Frequency) power supply 31 and / or a DC (Direct Current) power supply 32 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 described later is supplied to the at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as a plurality of lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Accordingly, the substrate support portion 11 includes at least one lower electrode.

[0029] 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 ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0030] Further, the substrate support portion 11 may include a temperature control 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 control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. Further, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0031] The shower head 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 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 plurality of gas introduction ports 13c. Further, the shower head 13 includes at least one upper electrode. Note that the gas introduction portion may include, in addition to the shower head 13, one or more side gas injection portions (SGI) attached to one or more openings formed in the side wall 10a.

[0032] 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 the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Further, the gas supply unit 20 may include one or more flow modulation devices for modulating or pulsing the flow rate of at least one process gas.

[0033] 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. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Accordingly, the RF power supply 31 can function as at least a part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. Also, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, and the ion component in the formed plasma can be drawn into the substrate W.

[0034] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation 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 generation unit 31a may be configured to generate a plurality of 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.

[0035] The second RF generation unit 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 generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0036] Also, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In one embodiment, the first DC generation unit 32a is connected to at least one lower electrode and is configured to generate a first DC signal. The generated first bias DC signal is applied to at least one lower electrode. In one embodiment, the second DC generation unit 32b is connected to at least one upper electrode and is configured to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0037] In various embodiments, at least one of 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 pulse waveform that is rectangular, trapezoidal, triangular, or a combination thereof. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from a DC signal is connected between the first DC generation unit 32a and at least one lower electrode. Accordingly, the first DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. When the second DC generation unit 32b and the waveform generation unit constitute a voltage pulse generation unit, the voltage pulse generation unit is connected to at least one upper electrode. The voltage pulses may have a positive polarity or a negative polarity. Also, the sequence of voltage pulses may include one or more positive-polarity voltage pulses and one or more negative-polarity voltage pulses within one cycle. Note that the first and second DC generation units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0038] The exhaust system 40 may be connected to, for example, the gas discharge 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 adjusted by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0039] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various processes described in the present disclosure. The control unit 2 can be configured to control each element of the plasma processing apparatus 1 to execute the 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 is realized, for example, by a computer 2a. The processing unit 2a1 can be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 and executed. The medium may be various storage media readable by the computer 2a, or may be 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 RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0040] Hereinafter, with reference to FIG. 2, the configuration of the upper electrode of a plasma processing apparatus according to one exemplary embodiment will be described. FIG. 2 is a cross-sectional view of the upper electrode according to one exemplary embodiment. The upper electrode 14 shown in FIG. 2 constitutes a shower head 13 in the plasma processing apparatus 1. The upper electrode 14 shown in FIG. 2 can be used as the upper electrode of a capacitively coupled plasma processing apparatus 1.

[0041] As shown in FIG. 2, the upper electrode 14 includes a first member 51, a second member 52, and at least one third member 53. Hereinafter, with reference to FIG. 2, FIGS. 3 and 4 will be referred to. FIG. 3 is a perspective view of a second member according to one exemplary embodiment. FIG. 4 is a cross-sectional view showing a part of the upper electrode according to one exemplary embodiment.

[0042] The first member 51 may be a top plate that defines the space (plasma processing space 10s) in the plasma processing chamber 10 from above. The first member 51 may have the axis AX as its central axis and may have a substantially disk shape. The axis AX extends in the vertical direction. The first member 51 is formed of a conductor. The first member 51 is formed of, for example, a silicon-containing material such as silicon or silicon carbide. As shown in FIG. 4, the first member 51 provides a plurality of first gas holes 51h. The plurality of first gas holes 51h penetrate the first member 51 in its plate thickness direction. The plurality of first gas holes 51h may constitute a plurality of gas inlets 13c.

[0043] As shown in FIGS. 2 and 4, the second member 52 is provided on or above the first member 51. The second member 52 is formed of a conductor. The second member 52 may be formed of a metal such as aluminum. As shown in FIG. 3, the second member 52 may have the axis AX as its central axis and may have a substantially disk shape. The second member 52 provides one or more second gas holes 52h. Each of the one or more second gas holes 52h constitutes a gas supply port 13a. Note that the second member 52 may be cooled. The second member 52 may provide a flow path through which a refrigerant flows inside.

[0044] At least one third member 53 is formed of a dielectric. The at least one third member 53 is formed of, for example, ceramics such as alumina and aluminum nitride, resins such as polytetrafluoroethylene (PTFE) and polyimide, or quartz. In one embodiment, the at least one third member 53 may be a porous body.

[0045] At least one third member 53 is provided between the first member 51 and the second member 52. At least one third member 53 defines at least one gas diffusion chamber 13b. A plurality of first gas holes 51h and one or more second gas holes 52h are connected to at least one gas diffusion chamber 13b.

[0046] In one embodiment, the upper electrode 14 may include a plurality of third members 53. As shown in FIG. 2, the number of the plurality of third members 53 may be three. Each of the plurality of third members 53 may define a plurality of gas diffusion chambers 13b as at least one gas diffusion chamber 13b. A plurality of first gas holes 51h (i.e., a plurality of gas inlets 13c) and corresponding one or more second gas holes 52h (i.e., gas supply ports 13a) may be connected to each of the plurality of gas diffusion chambers 13b.

[0047] As shown in FIG. 3, as an example, the second member 52 may define a plurality of grooves 52a that open downward. The number of the grooves 52a provided by the second member 52 is, for example, three. Each of the plurality of grooves 52a extends in the circumferential direction about the axis AX and has an annular shape. The plurality of grooves 52a are provided concentrically with respect to the axis AX. That is, the plurality of grooves 52a are arranged along the radial direction. Note that each of the radial direction and the circumferential direction is a direction based on the axis AX. As shown in FIG. 2, each of the plurality of third members 53 may be provided in the plurality of grooves 52a. In this case, each of the plurality of gas diffusion chambers 13b may be formed in the corresponding groove 52a.

[0048] Hereinafter, one gas diffusion chamber 13b among the plurality of gas diffusion chambers 13b of the upper electrode 14 and one third member 53 that defines the one gas diffusion chamber 13b will be described. As shown in FIG. 4, a plurality of first gas holes 51h and one or more second gas holes 52h are connected to the gas diffusion chamber 13b. As an example, one second gas hole 52h is connected to the gas diffusion chamber 13b.

[0049] In one embodiment, the upper electrode 14 may further include a seal member 55 (second seal member). The seal member 55 is sandwiched between the second member 52 and the third member 53. The seal member 55 may be an O-ring or a gasket. Note that the upper electrode 14 may include a plurality of seal members 55 corresponding to each of the plurality of third members 53.

[0050] In one embodiment, the third member 53 may include a side wall 53a, a top portion 53b, and a bottom portion 53c. The side wall 53a extends in the circumferential direction so as to surround the gas diffusion chamber 13b. The top portion 53b extends over the gas diffusion chamber 13b. The bottom portion 53c is disposed below the gas diffusion chamber 13b. The third member 53 may be a single member or may be composed of a plurality of members. For example, the side wall 53a, the top portion 53b, and the bottom portion 53c may be separate members. Alternatively, as shown in FIG. 4, in the third member 53, the top portion 53b may be a member separate from the side wall 53a and the bottom portion 53c, and the side wall 53a and the bottom portion 53c may be a single member and may be integrated with each other.

[0051] In one embodiment, the top portion 53b is disposed so as to face the opening end on the side of the gas diffusion chamber 13b of each of the plurality of first gas holes 51h. The top portion 53b may provide a through hole communicating with the second gas hole 52h. The through hole of the third member 53 may be aligned with the second gas hole 52h. The seal member 55 is, for example, an O-ring. In one embodiment, the seal member 55 may be sandwiched between the top portion 53b and the second member 52. As an example, the seal member 55 is disposed in a groove formed so as to surround the second gas hole 52h in the top portion 53b. In this case, the seal member 55 contacts the bottom surface of the groove 52a. Note that the thickness of the top portion 53b may be 3 mm or less.

[0052] In one embodiment, the bottom portion 53c may provide a plurality of third gas holes 53h. The plurality of third gas holes 53h penetrate the bottom portion 53c. Each of the plurality of third gas holes 53h connects a plurality of first gas holes 51h to the gas diffusion chamber 13b. The plurality of third gas holes 53h are aligned with the plurality of first gas holes 51h respectively. The center line of each of the plurality of third gas holes 53h may be aligned with the center line of each of the plurality of first gas holes 51h.

[0053] In one embodiment, the third member 53 may have a contact portion 53d that contacts the first member 51. The contact portion 53d is a part of the bottom portion 53c and is a portion that contacts the upper surface of the first member 51. The contact portion 53d is formed of a member having a lower coefficient of friction than the portion other than the contact portion 53d of the third member 53, that is, a low-friction member. The low-friction member is, for example, polytetrafluoroethylene (PTFE).

[0054] In one embodiment, the third member 53 may separate the boundary B between the first member 51 and the second member 52 from the gas diffusion chamber 13b. For example, the bottom portion 53c may separate the boundary B from the gas diffusion chamber 13b. In this case, the bottom portion 53c extends along the upper surface of the first member 51 and the two side surfaces of the second member 52 that define the groove 52a so as to fill two corners (an inner-diameter side corner and an outer-diameter side corner) formed by the upper surface of the first member 51 and the two side surfaces of the second member 52.

[0055] As described above, in the upper electrode 14, the gas diffusion chamber 13b is defined by the third member 53 formed of a dielectric. Therefore, even if electrons or positive ions enter the gas diffusion chamber 13b from each of the plurality of first gas holes 51h and collide with the third member 53 that defines the gas diffusion chamber 13b, the amount of secondary electrons emitted from the third member 53 is small. As a result, abnormal discharge in the upper electrode 14 is suppressed.

[0056] In the upper electrode 14, the seal member 55 suppresses the formation of the flow of the processing gas directed toward the gap between the second member 52 and the third member 53. Therefore, the flow of the processing gas formed in the gas diffusion chamber 13b is stabilized by the seal member 55.

[0057] Further, the seal member 55 exerts a reaction force on the third member 53 by being sandwiched between the second member 52 and the third member 53. The relative position of the third member 53 with respect to the first member 51 is fixed by this reaction force. Therefore, the friction between the third member 53 and the first member 51 is suppressed. As a result, the generation of particles due to the friction between the third member 53 and the first member 51 is suppressed.

[0058] Also, since the open ends of each of the plurality of first gas holes 51h face the top portion 53b, many of the electrons or positive ions that have entered the gas diffusion chamber 13b from each of the plurality of first gas holes 51h tend to collide with the top portion 53b. It is difficult for secondary electrons to be emitted from this top portion. Therefore, abnormal discharge in the upper electrode 14 is further suppressed.

[0059] Also, the electrons or positive ions that have entered the plurality of first gas holes 51h may collide with the wall surface that defines the plurality of third gas holes 53h before reaching the gas diffusion chamber 13b. The wall surface that defines the plurality of third gas holes 53h is difficult to emit secondary electrons. Therefore, abnormal discharge in the upper electrode 14 is further suppressed.

[0060] Also, in the upper electrode 14, the boundary B where abnormal discharge is likely to occur is blocked by the third member 53. Therefore, abnormal discharge in the upper electrode 14 is further suppressed.

[0061] Also, in the upper electrode 14, the frictional resistance between the first member 51 and the third member 53 is reduced by the contact portion 53d. As a result, the generation of particles due to the friction between the first member 51 and the third member 53 is suppressed.

[0062] The upper electrode according to various other exemplary embodiments will be described below. In the following, the differences from the upper electrode 14 regarding the upper electrodes according to various other exemplary embodiments will be described, and duplicate descriptions will be omitted.

[0063] First, refer to FIG. 5. FIG. 5 is a cross-sectional view showing a part of the upper electrode according to another exemplary embodiment. In the following, one gas diffusion chamber 13b out of the plurality of gas diffusion chambers 13b of the upper electrode 14A shown in FIG. 5 and a third member 53 defining the one gas diffusion chamber 13b will be described.

[0064] As shown in FIG. 5, the bottom 53c may not provide the third gas hole 53h. In this case, the third member 53 defines the gas diffusion chamber 13b together with the first member 51, and the bottom 53c surrounds the gas diffusion chamber 13b. In this case, the plurality of first gas holes 51h are directly connected to the gas diffusion chamber 13b. Note that, in this case, the thickness of the top 53b is, for example, 5 mm.

[0065] Next, refer to FIG. 6. FIG. 6 is a cross-sectional view showing a part of the upper electrode according to yet another exemplary embodiment. In the following, one gas diffusion chamber 13b out of the plurality of gas diffusion chambers 13b of the upper electrode 14B shown in FIG. 6 and a third member 53 defining the one gas diffusion chamber 13b will be described.

[0066] As shown in FIG. 6, the third member 53 may not include the side wall 53a and the top 53b. In this case, the third member 53 may include a bottom 53c that provides a plurality of third gas holes 53h. In this case, the third member 53 defines the gas diffusion chamber 13b together with the second member 52. Note that the third member 53 may not include a contact portion formed of a low-friction member.

[0067] As shown in FIG. 6, the upper electrode 14B may include two seal members 55 corresponding to one third member 53. Each of the two seal members 55 has an annular shape centered on the axis AX. One of the two seal members 55 is sandwiched between one of the two side wall surfaces (the inner diameter side wall surface) of the second member 52 defining the groove 52a and one side wall surface of the bottom portion 53c. The other of the two seal members 55 is sandwiched between the other of the two side wall surfaces (the outer diameter side wall surface) of the second member 52 defining the groove 52a and the other side wall surface of the bottom portion 53c.

[0068] Hereinafter, refer to FIG. 7. FIG. 7 is a cross-sectional view showing a part of the upper electrode according to still another exemplary embodiment. Hereinafter, one gas diffusion chamber 13b among the plurality of gas diffusion chambers 13b of the upper electrode 14C shown in FIG. 7 and the third member 53 defining the one gas diffusion chamber 13b will be described.

[0069] In one embodiment, as shown in FIG. 7, the boundary B between the first member 51 and the second member 52 may be separated from the gas diffusion chamber 13b by the seal member 55. As shown in FIG. 7, the upper electrode 14C may include a plurality of seal members 55 corresponding to one third member 53. In one example, as shown in FIG. 7, the upper electrode 14C includes four seal members 55. The four seal members 55 have an annular shape centered on the axis AX. Two of the four seal members 55 are sandwiched between one of the two side wall surfaces (the inner diameter side wall surface) of the second member 52 defining the groove 52a and the third member 53. Another two of the four seal members 55 are sandwiched between the other of the two side wall surfaces (the outer diameter side wall surface) of the second member 52 defining the groove 52a and the third member 53.

[0070] Of the four seal members 55, the two seal members 55 arranged above may be respectively arranged at two corners (the inner diameter side corner and the outer diameter side corner) on the upper end side of the groove 52a. The two seal members 55 arranged above among the four seal members 55 may be in contact with two side walls and the top portion 53b of the second member 52 that defines the groove 52a. Also, of the four seal members 55, the other two seal members 55 arranged below may be respectively arranged at two corners (the inner diameter side corner and the outer diameter side corner) formed by the upper surface of the first member 51 and the two side surfaces of the second member 52 that defines the groove 52a. Each of the other two seal members 55 arranged below among the four seal members 55 may be in contact with the side wall of the third member 53 that defines the groove 52a and the upper surface of the first member 51. In this case, the thickness of the top portion 53b is, for example, 5 mm or more.

[0071] Also, in the upper electrode 14C, a boundary B where abnormal discharge is likely to occur is separated from the gas diffusion chamber 13b by the seal member 55. Therefore, abnormal discharge in the upper electrode 14C is further suppressed.

[0072] Hereinafter, refer to FIG. 8. FIG. 8 is a cross-sectional view showing a part of an upper electrode according to still another exemplary embodiment. Hereinafter, one gas diffusion chamber 13b among a plurality of gas diffusion chambers 13b of the upper electrode 14D shown in FIG. 8 and the third member 53 that defines the one gas diffusion chamber 13b will be described.

[0073] As shown in FIG. 8, the upper electrode 14D may further include a seal member 54 (first seal member). The seal member 54 may be an O-ring or a gasket. The upper electrode 14 may include a plurality of seal members 54 corresponding to each of the plurality of third members 53. Hereinafter, at least one seal member 54 corresponding to one third member 53 will be described. The upper electrode 14D may include two seal members 54 corresponding to the third member 53. Each seal member 54 is sandwiched between the first member 51 and the third member 53. More specifically, each seal member 54 may be sandwiched between the first member 51 and the bottom portion 53c.

[0074] Each sealing member 54 is, for example, an O-ring. Each of the two sealing members 54 may be disposed at two corners (an inner-diameter-side corner and an outer-diameter-side corner) formed by the upper surface of the first member 51 and two side surfaces of the second member 52 that define the groove 52a. Each of the two sealing members 54 may be sandwiched between the bottom portion 53c of the third member 53 and the upper surface of the first member 51. As shown in FIG. 8, each of the two sealing members 54 may separate the boundary B between the first member 51 and the second member 52 from the gas diffusion chamber 13b. Further, the sealing member 54 may separate the boundary B between the first member 51 and the second member 52 from the third gas hole 53h. In another embodiment, the sealing member 55 may separate the boundary B between the first member 51 and the second member 52 from the third gas hole 53h.

[0075] In the upper electrode 14D, the sealing member 54 suppresses the formation of the flow of the processing gas toward the gap between the first member 51 and the third member 53. Accordingly, the flow of the processing gas formed in the gas diffusion chamber 13b is stabilized by the sealing member 54.

[0076] Also, in the upper electrode 14D, particles that may be generated by the friction between the third member 53 and the first member 51 are suppressed from entering the plurality of first gas holes 51h.

[0077] Also, in the upper electrode 14D, the boundary B where abnormal discharge is likely to occur is separated from the gas diffusion chamber 13b by the sealing member 54. Accordingly, abnormal discharge in the upper electrode 14D is further suppressed.

[0078] Also, in the upper electrode 14D, particles that may be generated by the friction between the third member 53 and the first member 51 are suppressed from entering the plurality of third gas holes 53h.

[0079] Refer to FIG. 9 below. FIG. 9 is a cross-sectional view showing a part of an upper electrode according to still another exemplary embodiment. Hereinafter, one of the plurality of gas diffusion chambers 13b of the upper electrode 14E shown in FIG. 9 and a third member 53 that defines the one gas diffusion chamber 13b will be described. As shown in FIG. 9, the upper electrode 14E may not include the seal members 54 and 55. In other embodiments, the upper electrode may include at least one of the seal members 54 and 55.

[0080] Although various exemplary embodiments have been described above, various additions, omissions, substitutions, and changes may be made without being limited to the above-described exemplary embodiments. Also, it is possible to form other embodiments by combining elements in different embodiments.

[0081] From the above description, it will be understood that the various embodiments of the present disclosure have been described herein for the purpose of illustration and that various changes can be made without departing from the scope and gist of the present disclosure. Therefore, the various embodiments disclosed herein are not intended to be limiting, and the true scope and gist are indicated by the appended claims.

Description of Reference Numerals

[0082] 1... Plasma processing apparatus, 10... Plasma processing chamber, 10s... Plasma processing space, 11... Substrate support portion, 13... Shower head, 13b... Gas diffusion chamber, 14, 14A, 14B, 14C, 14D... Upper electrode, 51... First member, 51h... First gas hole, 52... Second member, 52a... Groove, 52h... Second gas hole, 53... Third member, 53a... Side wall, 53b... Top portion, 53c... Bottom portion, 53d... Contact portion, 53h... Third gas hole, 54... Seal member (first seal member), 55... Seal member (second seal member), AX... Axis, B... Boundary.

Claims

1. An upper electrode that constitutes a shower head in a capacitively coupled plasma processing apparatus, a first member formed of a conductor, providing a plurality of first gas holes penetrating the first member, the first member, a second member formed of a conductor and provided on the first member, providing one or more second gas holes, the second member, a third member formed of a dielectric, provided between the first member and the second member, defining at least one gas diffusion chamber to which the plurality of first gas holes and the one or more second gas holes are connected, at least one third member, comprising: wherein, as the at least one third member, a plurality of third members are provided, the plurality of third members define a plurality of gas diffusion chambers as the at least one gas diffusion chamber, the plurality of gas diffusion chambers are arranged along a radial direction with respect to a central axis of the first member extending in a vertical direction, upper electrode.

2. An upper electrode that constitutes a shower head in a capacitively coupled plasma processing apparatus, a first member formed of a conductor, providing a plurality of first gas holes penetrating the first member, the first member, a second member formed of a conductor and provided on the first member, providing one or more second gas holes, the second member, a third member formed of a dielectric, provided between the first member and the second member, defining at least one gas diffusion chamber to which the plurality of first gas holes and the one or more second gas holes are connected, at least one third member, comprising: the at least one third member has a contact portion that contacts the first member, the contact portion is formed of a low friction member having a lower friction coefficient than other portions of the at least one third member, upper electrode.

3. The upper electrode according to claim 2, wherein the dielectric is a porous body.

4. An upper electrode that constitutes a shower head in a capacitively coupled plasma processing apparatus, a first member formed of a conductor, providing a plurality of first gas holes penetrating the first member, the first member, a second member formed of a conductor and provided on the first member, providing one or more second gas holes, the second member, It is formed of a dielectric, provided between the first member and the second member, and defines at least one gas diffusion chamber to which the plurality of first gas holes and the one or more second gas holes are connected. At least one third member, comprising The dielectric is a porous body. Upper electrode.

5. The upper electrode according to any one of claims 1 to 4, further comprising at least one of a first seal member sandwiched between the first member and the at least one third member and a second seal member sandwiched between the second member and the at least one third member.

6. The at least one third member a side wall extending in the circumferential direction so as to surround the at least one gas diffusion chamber; a top portion extending over the at least one gas diffusion chamber; including The second seal member is sandwiched between either the side wall and the second member or between the top portion and the second member. The upper electrode according to claim 5.

7. The upper electrode according to claim 6, wherein the top portion is disposed so as to face the opening end on the side of the at least one gas diffusion chamber of each of the plurality of first gas holes.

8. The upper electrode according to any one of claims 5 to 7, wherein the at least one third member includes a bottom portion disposed below the at least one gas diffusion chamber.

9. The upper electrode according to claim 8, wherein the bottom portion provides a plurality of third gas holes respectively aligned with the plurality of first gas holes.

10. The upper electrode according to claim 8 or 9, wherein the second seal member is sandwiched between the second member and the bottom portion.

11. The upper electrode according to any one of claims 8 to 10, wherein the first seal member is sandwiched between the first member and the bottom portion.

12. The upper electrode according to any one of claims 5 to 11, wherein at least one of the first seal member and the second seal member separates the boundary between the first member and the second member from the at least one gas diffusion chamber.

13. The upper electrode according to claim 9, wherein at least one of the first seal member and the second seal member separates the boundary between the first member and the second member from the plurality of third gas holes.

14. The at least one third member separates a boundary between the first member and the second member from the at least one gas diffusion chamber, the top electrode according to any one of claims 1 to 13.

15. At least one of the first sealing member and the second sealing member is an O-ring or a gasket, the top electrode according to any one of claims 5 to 13.

16. A plasma processing chamber that provides a processing space therein, A substrate support provided in the plasma processing chamber, The top electrode according to any one of claims 1 to 15, provided above the substrate support, the top electrode, and A plasma processing apparatus comprising.

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