JP2023053918A - Upper electrode assembly and plasma processing apparatus - Google Patents

Abstract

To obtain stable electric conduction between a first member and a second member that an upper electrode assembly has.SOLUTION: There is provided an upper electrode assembly of a plasma processing apparatus, and the upper electrode assembly comprises a first member formed of conductive material, a second member formed of conductive material and provided on the first member, and a conductive member interposed between the first member and second member and letting the first member and second member electrically conduct to each other, wherein the conductive member contains nickel, chromium and molybdenum and also has its surface processed.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to upper electrode assemblies and plasma processing apparatus.

A capacitively coupled plasma processing apparatus is used as one type of plasma processing apparatus. For example, Patent Literature 1 discloses a capacitively coupled plasma processing apparatus. A capacitively coupled plasma processing apparatus includes an upper electrode. The upper electrode includes a shower plate and an upper electrode body. A metal spiral tube is provided between the shower plate and the upper electrode body. A metal spiral tube ensures electrical continuity between the shower plate and the upper electrode body.

JP 2004-356509 A

The present disclosure provides an upper electrode assembly of a plasma processing apparatus and a plasma processing apparatus capable of achieving stable electrical conduction between a first member and a second member of the upper electrode assembly.

According to one aspect of the present disclosure, an upper electrode assembly for a plasma processing apparatus includes: a first member formed from a conductive material; and a conductive member interposed between the first member and the second member to electrically connect the first member and the second member, wherein the An upper electrode assembly is provided wherein the conducting member comprises nickel, chromium and molybdenum and is surface treated.

According to one aspect, stable electrical continuity can be achieved between the first member and the second member of the upper electrode assembly.

4 is an enlarged view showing an example of the upper electrode assembly according to the first embodiment; FIG. FIG. 5 is an enlarged view showing an example of an upper electrode assembly according to the second embodiment; The figure which shows an example of the plasma processing apparatus which concerns on one Embodiment.

Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and redundant description may be omitted.

[Upper electrode assembly]
SUMMARY Exemplary embodiments of the present disclosure relate to upper electrode assemblies and plasma processing apparatus. The upper electrode assembly 3 (see FIG. 3) in the present disclosure has a first member and a second member. The first member is formed from an electrically conductive material. The second member is formed from an electrically conductive material and overlies the first member.

The upper electrode assembly 3 has a conductive member that is interposed between the first member and the second member to electrically connect the first member and the second member to each other. The upper electrode assembly 3 contains nickel, chromium and molybdenum between the first member and the second member, and is surface-treated.

In the first embodiment, as an example of the first member and the second member of the upper electrode assembly 3, the upper electrode 31 and the cooling plate 32 of FIG. 1 are taken as an example. In the second embodiment, as an example of the first member and the second member of the upper electrode assembly 3, the ground ring 33 and the third annular member 36 of FIG. 2 are taken as an example.

<First Embodiment>
An upper electrode assembly 3 according to the first embodiment will be described with reference to FIG. FIG. 1 is an enlarged view showing an example of the upper electrode assembly 3 according to the first embodiment. FIG. 1 is an enlarged view of part of the outer peripheral side of the upper electrode assembly 3 of FIG.

The upper electrode assembly 3 has an upper electrode 31 and a cooling plate 32 . The upper electrode 31 is an example of the first member. The cooling plate 32 is an example of a second member. The conducting member 41 is interposed between the upper electrode 31 and the cooling plate 32 to electrically connect the upper electrode 31 and the cooling plate 32 to each other. For example, the conducting member 41 is provided along the entire circumference between the upper electrode 31 and the cooling plate 32 . The conductive member 41 is, for example, a spiral tube provided along the entire circumference of the upper electrode 31 in the circumferential direction.

A first annular member 34 , a second annular member 35 provided under the first annular member 34 , and a third An annular member 36 is provided. A first annular member 34 surrounds the cooling plate 32 . The second annular member 35 has an L-shaped cross section in the radial direction, and surrounds the upper electrode 31 via a fastening screw portion 52 that fastens the upper electrode 31 and the cooling plate 32 . The third annular member 36 is adjacent to the second annular member 35 at the outer periphery of the second annular member 35 and surrounds the second annular member 35 . A ground ring 33 is provided below the second annular member 35 and the third annular member 36 . The ground ring 33 is provided so as to cover the lower surface of the outermost periphery of the upper electrode 31 and the lower surfaces of the second annular member 35 and the third annular member 36 . The third annular member 36 is an example of an annular member having a heater 36 a located on the periphery of the upper electrode 31 .

The first to third annular members 34 to 36 and the ground ring 33 are annular. The first to third annular members 34 to 36 are made of insulating material such as quartz. A heater 36 a is provided inside the third annular member 36 . The temperature of the upper electrode assembly 3 can be controlled by the heater 36a. The ground ring 33 is made of a conductive material such as silicon and grounded.

The fastening screw portion 52 passes through a clamp 51 provided between the upper electrode 31 and the second annular member 35 . In a state in which the clamp 51 is engaged with the outer peripheral lower surface of the upper electrode 31 and lifts the upper electrode 31, the lower portion of the fastening screw portion 52 and the clamp 51 are engaged. The upper portion of the fastening screw portion 52 is inserted into the recess 32a of the cooling plate 32 and fixed to the cooling plate 32, and the clamp 51 is pushed up through the fastening screw portion 52 by the spring 52a. As a result, the upper electrode 31 is fixed by the fastening screw portion 52 and lifted up via the clamp 51 .

The upper electrode 31 is a conductive member containing silicon, and is made of, for example, silicon (Si), silicon carbide (SiC), polysilicon (Poly-Si), or silicon oxide (SiO ₂ ). The cooling plate 32 is a conductive member containing aluminum, and is made of, for example, aluminum (Al) or alumina (Al ₂ O ₃ ).

As described above, the upper electrode 31 and the cooling plate 32 are made of different materials and have different thermal expansions. Therefore, a gap is generated between the upper electrode 31 and the cooling plate 32 due to plasma generated in the processing chamber and heat input from the heater 36a.

Conventionally, an SUS spiral, that is, a spiral stainless steel, has been used to interpose between the upper electrode 31 and the cooling plate 32 to electrically connect the upper electrode 31 and the cooling plate 32 to each other. Since the conventional SUS spiral lacks a restoring force, electrical continuity between the upper electrode 31 and the cooling plate 32 cannot be ensured in some cases when the upper electrode 31 and the cooling plate 32 are crushed.

On the other hand, the conductive member 41 according to the present embodiment contains nickel, chromium and molybdenum and is surface-treated. For example, the conductive member 41 according to the present embodiment may include INCONEL (both registered trademarks) or HASTELLOY (both registered trademarks).

For example, the conducting member 41 according to one embodiment may include INCONEL® 625. In this embodiment, a conducting member 41 containing Inconel (registered trademark) 625 and having a surface subjected to plasma nitriding, which is an example of surface treatment, is placed between the upper electrode 31 and the cooling plate 32 .

The conductive member 41 of the present embodiment is harder than the conventional SUS spiral, and has characteristics of "strong corrosion resistance", "high heat resistance", and "strong strength". Therefore, since the conductive member 41 is excellent in plasma resistance, it exhibits a high restoring force even if the conductive member 41 is crushed between the upper electrode 31 and the cooling plate 32 . Therefore, by using this conducting member 41, it is possible to ensure more stable electrical conduction between the upper electrode 31 and the cooling plate 32 than with the conventional SUS spiral.

Furthermore, the surface of the conductive member 41 of this embodiment is subjected to plasma nitriding treatment. Such a surface treatment of the conductive member 41 increases plasma resistance, so that the conductive member 41 can be more effectively prevented from being damaged by plasma.

The plasma nitriding process is a process of exposing the conductive member 41 to plasma of a gas containing nitrogen to nitride the surface of the conductive member 41 to form a film. However, the surface treatment of the conducting member 41 is not limited to the plasma nitriding treatment as long as the plasma resistance can be increased. For example, the surface treatment of the conductive member 41 may be plasma nitriding treatment, plasma carbonization treatment, heat treatment, or film formation by CVD (Chemical Vapor Deposition). Conductive member 41 may have a nitrogen-containing surface or a carbon-containing surface.

The plasma carbonization process is a process of carbonizing the surface of the conduction member 41 by exposing the conduction member 41 to plasma of gas containing carbon. The heat treatment is processing for processing the surface of the conducting member 41 by heating the conducting member 41 . The CVD process is a process of covering the surface of the conducting member 41 by forming a film on the surface of the conducting member 41 by thermal CVD or plasma CVD.

By using a conductive member 41 having a larger diameter of the spiral tube of the conductive member 41, more stable electrical conduction can be ensured between the upper electrode 31 and the cooling plate 32. FIG. The cross-sectional diameter of the conductive member 41 is about 1 mm to 5 mm.

<Second embodiment>
An upper electrode assembly 3 according to the second embodiment will be described with reference to FIG. FIG. 2 is an enlarged view showing an example of the upper electrode assembly 3 according to the second embodiment. FIG. 2 is an enlarged view of part of the outer peripheral side of the upper electrode assembly 3 of FIG. In the upper electrode assembly 3 according to the second embodiment shown in FIG. 2, the conducting member 41 shown in FIG. 1 is not provided, but the conducting member 42 is provided. Since other configurations are the same as those of the upper electrode assembly 3 according to the first embodiment, the configuration of the conductive member 42 and its surroundings will be described below, and description of other configurations will be omitted.

The conducting member 42 is interposed between the ground ring 33 and the third annular member 36 (annular member) having the heater 36a, and electrically connects the ground ring 33 and the third annular member 36 to each other. The ground ring 33 is an example of the first member. The third annular member 36 is an example of a second member. For example, the conductive member 42 is provided along the entire circumference between the ground ring 33 and the third annular member 36 . The conduction member 42 is, for example, a spiral tube provided along the entire circumference of the ground ring 33 in the circumferential direction.
This also ensures more stable electrical conduction between the ground ring 33 and the third annular member 36 than the conventional SUS spiral.

Plasma enters the gap between the ground ring 33 and the third annular member 36 . Therefore, when the conventional SUS spiral is exposed to plasma, the surface of the SUS spiral is damaged, and electrical continuity between the ground ring 33 and the third annular member 36 cannot be ensured in some cases.

In the second embodiment, a conductive member 42 containing Inconel (registered trademark) 625 and having a surface subjected to plasma nitriding, which is an example of surface treatment, is installed between the ground ring 33 and the third annular member 36 .

The conducting member 42 of the present embodiment is harder than the conventional SUS spiral, and has characteristics of "strong corrosion resistance", "high heat resistance", and "high strength". Therefore, since the conductive member 42 is excellent in plasma resistance, it exhibits a high restoring force between the ground ring 33 and the third annular member 36 even if the conductive member 42 is exposed to plasma during the process. Therefore, by using this conducting member 42, it is possible to ensure more stable electrical conduction between the ground ring 33 and the third annular member 36 than with the conventional SUS spiral.

In FIG. 2, the conductive member 41 of FIG. 1 is not provided. A conductive member 41 for conducting may be arranged. This makes it possible to ensure more stable electrical continuity between the ground ring 33 and the third annular member 36 and between the upper electrode 31 and the cooling plate 32 .

In the first and second embodiments, the potential of the first member and the potential of the second member may be floating potential or ground potential. That is, the potential between the upper electrode 31 and the cooling plate 32 may be a floating potential or a ground potential. Also, the potential between the ground ring 33 and the third annular member 36 may be a floating potential or a ground potential. In the case of floating potential, since there is no guarantee that the first member and the second member have the same potential, the conducting member 41 and/or the conducting member 42 should be provided between the first member and the second member. Thus, electrical continuity between the first member and the second member can be ensured more stably.

[Plasma processing equipment]
An example of a plasma processing apparatus 100 having an upper electrode assembly 3 according to one embodiment will now be described with reference to FIG. The plasma processing apparatus (parallel plate type plasma processing apparatus) of FIG. 3 includes an upper electrode assembly according to the present disclosure as an upper electrode assembly 3 .

FIG. 3 is a diagram for explaining a configuration example of a capacitively coupled plasma (CCP) type plasma processing apparatus.

Plasma processing apparatus 100 has a processing chamber 1 , an upper electrode assembly 3 and a lower electrode 4 . RF (Radio Frequency) power is supplied from the RF power supply 6 to the upper electrode assembly 3 (upper electrode 31 (see FIG. 1)) and from the RF power supply 7 to the lower electrode 4 . RF power supply 6 and RF power supply 7 may provide RF power at different RF frequencies.

A bottom electrode 4 is positioned within the processing chamber 1 . The lower electrode 4 includes an electrostatic chuck (ESC) 5 to attract and support a substrate W, which is an example of a semiconductor wafer. The lower electrode 4 is an example of a substrate supporting portion. An upper electrode assembly 3 is provided above and opposite the lower electrode 4 within the processing chamber 1 .

The lower electrode 4 may include a temperature regulation module configured to regulate at least one of the electrostatic chuck 5 and the substrate W to a target temperature. The temperature control module may include heaters, heat transfer media, flow paths, or combinations thereof. A heat transfer fluid, such as brine or gas, flows through the channel. In one embodiment, channels are formed in the bottom electrode 4 and one or more heaters are located in the electrostatic chuck 5 . The lower electrode 4 may also include a heat transfer gas supply configured to supply a heat transfer gas to the gap between the back surface of the substrate W and the electrostatic chuck 5 .

The plasma processing apparatus 100 includes a gas introduction section. The gas introduction is configured to introduce at least one process gas into the process chamber 1 . A gas source 8 is connected to the gas inlet and supplies a processing gas into the processing chamber 1 from the gas inlet. The gas introduction part may additionally include one or more side gas injectors (SGI) attached to one or more openings formed in the side wall of the processing chamber 1 .

Gas source source 8 is configured to supply at least one process gas to plasma processing space 10s via a flow controller. Flow controllers may include, for example, mass flow controllers or pressure-controlled flow controllers. Additionally, plasma processing apparatus 100 may include one or more flow modulation devices that modulate or pulse the flow rate of at least one process gas.

The processing chamber 1 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 exhaust port for exhausting gas from the plasma processing space 10s. Processing chamber 1 is grounded.

The exhaust device 9 is connected to the processing chamber 1 and exhausts the inside of the processing chamber 1 . The exhaust device 9 can be connected to a gas outlet provided at the bottom of the processing chamber 1, for example. The evacuation device 9 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the plasma processing space 10s. Vacuum pumps may include turbomolecular pumps (TMP), dry pumps, or combinations thereof.

RF power is supplied to at least one of the upper electrode 31 and the lower electrode 4 and the plasma 2 is formed in the vicinity of the substrate W between the upper electrode 31 and the lower electrode 4 . A plurality of RF power sources 6 and RF power sources 7 may be connected to the same electrode among the upper electrode 31 and the lower electrode 4 .

Accordingly, RF power source 6 and RF power source 7 may function as at least part of a plasma generator configured to generate a plasma from one or more process gases in processing chamber 1 . Further, by supplying a bias RF signal to the lower electrode 4, a bias potential is generated in the substrate W, and ion components in the formed plasma can be drawn into the substrate W. FIG.

RF power supply 6 is coupled to upper electrode 31 via an impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. An RF power supply 6 may be coupled to the lower electrode 4 via an impedance matching circuit and configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency within the range of 10 MHz to 150 MHz. In one embodiment, RF power supply 6 may be configured to generate multiple source RF signals having different frequencies. One or more source RF signals generated are supplied to the bottom electrode 4 and/or the top electrode 31 .

An RF power supply 7 is coupled to the lower electrode 4 via an impedance matching circuit and 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 within the range of 100 kHz to 60 MHz. In one embodiment, RF power supply 7 may be configured to generate multiple bias RF signals having different frequencies. One or more bias RF signals generated are supplied to the bottom electrode 4 . Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

Additionally, a DC voltage (direct voltage) may be supplied to the upper electrode assembly 3 from a variable direct current (DC) power supply 10 . In various embodiments, the DC voltage may be pulsed. In this case, a sequence of voltage pulses is applied to the upper electrode 31 . The voltage pulses may have rectangular, trapezoidal, triangular, or combinations thereof pulse waveforms. In one embodiment, a DC voltage (direct voltage) may be supplied to the lower electrode 4 from a variable direct current (DC) power supply 10 .

Controller 50 processes computer-executable instructions that cause plasma processing apparatus 100 to perform various operations described in this disclosure. Controller 50 may be configured to control elements of plasma processing apparatus 100 to perform the various processes described herein. In one embodiment, some or all of controller 50 may be included in plasma processing apparatus 100 . Controller 50 may include a processing unit, a storage unit, and a communication interface. The control device 50 is implemented by, for example, a computer. The processing unit can be configured to read a program from the storage unit and execute various control operations by executing the read program. This program may be stored in the storage unit in advance, or may be obtained via a medium when necessary. The acquired program is stored in the storage unit, read from the storage unit and executed by the processing unit. The medium may be various computer-readable storage media or a communication line connected to a communication interface. The processing unit may be a CPU (Central Processing Unit). The storage unit may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the plasma processing apparatus 100 via a communication line such as a LAN (Local Area Network).

The embodiments disclosed above include, for example, the following aspects.
(Appendix 1)
An upper electrode assembly for a plasma processing apparatus, comprising:
a first member formed from an electrically conductive material;
a second member formed from an electrically conductive material and disposed over the first member;
a conducting member interposed between the first member and the second member and conducting the first member and the second member to each other;
The upper electrode assembly, wherein the conducting member contains nickel, chromium and molybdenum and is surface-treated.
(Appendix 2)
The conductive member includes INCONEL (both registered trademarks) or HASTELLOY (both registered trademarks),
The upper electrode assembly of paragraph 1.
(Appendix 3)
The conductive member comprises INCONEL (registered trademark) 625 (INCONEL (registered trademark) 625),
2. The upper electrode assembly of paragraph 2.
(Appendix 4)
The surface treatment is plasma nitriding treatment, plasma carbonization treatment, heat treatment, or film formation by CVD.
The upper electrode assembly according to any one of Appendixes 1-3.
(Appendix 5)
The conducting member has a nitrogen-containing surface or a carbon-containing surface,
5. The upper electrode assembly of paragraph 4.
(Appendix 6)
The first member is a conductive member containing silicon, and the second member is a conductive member containing aluminum,
6. The upper electrode assembly according to any one of clauses 1-5.
(Appendix 7)
wherein the first member is an upper electrode and the second member is a cooling plate;
The upper electrode assembly according to any one of clauses 1-6.
(Appendix 8)
The first member is a ground ring located on the periphery of the upper electrode, and the second member is an annular member having a heater located on the periphery of the upper electrode.
The upper electrode assembly according to any one of clauses 1-6.
(Appendix 9)
the potential of the first member and the potential of the second member are floating potential or ground potential;
The upper electrode assembly according to any one of clauses 1-8.
(Appendix 10)
a processing chamber, a substrate support for supporting a substrate in the processing chamber, and an upper electrode assembly provided above the substrate support in the processing chamber and facing the substrate support;
The upper electrode assembly comprises:
a first member formed from an electrically conductive material;
a second member formed from an electrically conductive material and disposed over the first member;
a conducting member interposed between the first member and the second member and conducting the first member and the second member to each other;
The plasma processing apparatus, wherein the conductive member contains nickel, chromium and molybdenum and is surface-treated.

It should be noted that the present invention is not limited to the configurations shown here, such as combinations with other elements, etc., in the configurations described in the above embodiments. These points can be changed without departing from the gist of the present invention, and can be determined appropriately according to the application form. In addition, the items described in the multiple embodiments can be configured in other configurations within a consistent range, and can be combined within a consistent range.

The plasma processing apparatus of the present disclosure can be applied to any of a single-wafer apparatus for processing substrates one by one, a batch apparatus and a semi-batch apparatus for collectively processing a plurality of substrates.

This application claims priority to US Provisional Application No. 63/261,955 filed October 1, 2021 with the US Patent Office, the entire contents of which are hereby incorporated by reference.

3 upper electrode assembly 31 upper electrode 32 cooling plate 33 ground ring 34 first annular member 35 second annular member 36 third annular member 36a heater 41, 42 conduction member 50 controller 100 plasma processing apparatus

Claims (10)

An upper electrode assembly for a plasma processing apparatus, comprising:
a first member formed from an electrically conductive material;
a second member formed from an electrically conductive material and disposed over the first member;
a conducting member interposed between the first member and the second member and conducting the first member and the second member to each other;
The upper electrode assembly, wherein the conducting member contains nickel, chromium and molybdenum and is surface-treated. The conductive member includes Inconel (registered trademark) or Hastelloy (registered trademark),
The upper electrode assembly of Claim 1. The conductive member includes Inconel (registered trademark) 625,
3. The upper electrode assembly of claim 2. The surface treatment is plasma nitriding treatment, plasma carbonization treatment, heat treatment, or film formation by CVD.
The upper electrode assembly according to any one of claims 1-3. The conducting member has a nitrogen-containing surface or a carbon-containing surface,
5. The upper electrode assembly of claim 4. The first member is a conductive member containing silicon, and the second member is a conductive member containing aluminum,
The upper electrode assembly according to any one of claims 1-3. wherein the first member is an upper electrode and the second member is a cooling plate;
The upper electrode assembly according to any one of claims 1-3. The first member is a ground ring located on the periphery of the upper electrode, and the second member is an annular member having a heater located on the periphery of the upper electrode.
The upper electrode assembly according to any one of claims 1-3. the potential of the first member and the potential of the second member are floating potential or ground potential;
The upper electrode assembly according to any one of claims 1-3. a processing chamber, a substrate support for supporting a substrate in the processing chamber, and an upper electrode assembly provided above the substrate support in the processing chamber and facing the substrate support;
The upper electrode assembly comprises:
a first member formed from an electrically conductive material;
a second member formed from an electrically conductive material and disposed over the first member;
a conducting member interposed between the first member and the second member and conducting the first member and the second member to each other;
The plasma processing apparatus, wherein the conductive member contains nickel, chromium and molybdenum and is surface-treated.

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