Plasma probe device and plasma processing device

Abstract

The plasma characteristics are accurately measured using a plasma probe device installed on a component exposed to the internal space side of the processing vessel where the plasma is generated. [Solution] A plasma probe device provided on a member exposed to the internal space side of a processing vessel where plasma is generated, comprising: a probe cover including a cylindrical metal cover and a cylindrical insulating cover provided inside the metal cover; a rod-shaped probe body provided inside the insulating cover; and a metal plate connected to the tip of the probe body and covering the tip of the probe cover, wherein a gas discharge port for supplying gas to the space between the metal plate and the tip of the probe cover is provided on the probe body side from the peripheral end of the probe cover.

Description

Technical Field

[0001] The present disclosure relates to a plasma probe device and a plasma processing device.

Background Art

[0002] Patent Document 1 discloses a plasma probe device that senses plasma generated in a plasma generation space. The plasma probe device disclosed in Patent Document 1 has an antenna portion attached via an O-ring to an opening formed in a side wall of a processing container. The antenna portion is provided at the tip of the plasma probe device. The tip of the antenna portion is a disc-shaped member and is arranged to close the opening of the opening via an O-ring. The front surface of the antenna portion and the back surface near the opening of the wall of the processing container are isolated, and a gap with a predetermined width is formed. The region from the opening to the O-ring on the front surface of the antenna portion is covered with a film of an insulator. Also, at least the region from the side surface of the opening to the back surface of the opening and through to the O-ring on the wall surface of the processing container is covered with a film of an insulator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology according to the present disclosure accurately measures the characteristics of plasma using a plasma probe device provided on a member exposed on the inner space side of a processing container in which plasma is generated.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a plasma probe device provided on a member exposed to the internal space side of a processing vessel where plasma is generated, comprising: a probe cover including a cylindrical metal cover and a cylindrical insulating cover provided inside the metal cover; a rod-shaped probe body provided inside the insulating cover; and a metal plate connected to the tip of the probe body and covering the tip of the probe cover, wherein a gas discharge port for supplying gas to the space between the metal plate and the tip of the probe cover is provided on the probe body side from the peripheral end of the probe cover. [Effects of the Invention]

[0006] According to this disclosure, the properties of the plasma can be accurately measured using a plasma probe device provided on a component exposed to the internal space side of the processing vessel where the rasma is generated. [Brief explanation of the drawing]

[0007] [Figure 1] This is a longitudinal cross-sectional view showing a schematic configuration of a plasma processing apparatus equipped with a plasma probe device according to this embodiment. [Figure 2] This is a cross-sectional view showing a schematic configuration of a plasma probe device. [Figure 3] This is a magnified view of a portion of Figure 2. [Figure 4] This is a schematic cross-sectional view illustrating the configuration of a plasma probe device to illustrate another example of a gas outlet. [Figure 5] This is a magnified view of a portion of Figure 4. [Modes for carrying out the invention]

[0008] The plasma probe device according to this embodiment will be described below with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted.

[0009] <Plasma Processing Equipment> Figure 1 is a longitudinal cross-sectional view showing a schematic configuration of a plasma processing apparatus equipped with a plasma probe device according to this embodiment.

[0010] The plasma processing apparatus 1 shown in Figure 1 comprises a processing container 11 for housing a wafer W and performing plasma processing, a mounting table 12 positioned inside the processing container 11 on which the wafer W is placed, a gas supply mechanism 13 for supplying gas into the processing container 11, an exhaust device 14 for exhausting the inside of the processing container 11, a microwave introduction device 15 for generating microwaves to generate plasma inside the processing container 11 and introducing the microwaves into the processing container 11, and a control unit 16. The processing container 11 is grounded.

[0011] The processing container 11 is made of a metal material such as aluminum and its alloys, has a substantially cylindrical shape, and has a plate-shaped top portion 21 and bottom portion 22, and side walls 23 connecting them. The microwave introduction device 15 is provided on top of the processing container 11 and functions as a plasma generation means that generates plasma by introducing electromagnetic waves (microwaves) into the processing container 11.

[0012] The top plate 21 has multiple openings into which the microwave radiation mechanism 53 and gas introduction nozzle 41 of the microwave introduction device 15, which will be described later, are fitted. The side wall 23 has an inlet / outlet 24 for loading and unloading wafers W, which are substrates to be processed, between the processing container 11 and a transport chamber (not shown) adjacent to it. The inlet / outlet 24 is opened and closed by a gate valve 25. An exhaust device 14 is provided at the bottom 22. The exhaust device 14 is connected to an exhaust pipe 26 provided at the bottom 22. The exhaust device 14 is equipped with a vacuum pump (not shown). This vacuum pump exhausts the inside of the processing container 11 via the exhaust pipe 26. The pressure inside the processing container 11 is controlled by a pressure control valve (not shown) provided in the exhaust device 14.

[0013] The mounting table 12 is disc-shaped and made of ceramics such as AlN. The mounting table 12 is supported by a cylindrical support member 30 made of ceramics such as AlN that extends upward from the center of the bottom of the processing container 11. A guide ring 31 for guiding the wafer W is provided on the outer edge of the mounting table 12. Inside the mounting table 12, a lifting pin (not shown) for raising and lowering the wafer W is provided so as to be able to protrude from and retract to the upper surface of the mounting table 12. Furthermore, a heater 32 is embedded inside the mounting table 12, and this heater 32 heats the wafer W on the mounting table 12 with power supplied from a heater power supply 33.

[0014] A thermocouple (not shown) is inserted into the mounting table 12, and the wafer W can be heated to a desired temperature based on the signal from the thermocouple. An electrode 34, approximately the same size as the wafer W, is embedded above the heater 32 in the mounting table 12, and a high-frequency power supply 35 is electrically connected to this electrode 34. A high-frequency bias for attracting ions is applied to the mounting table 12 from this high-frequency power supply 35. Note that the high-frequency power supply 35 may not be necessary depending on the characteristics of the plasma processing. In this example, a high-frequency bias was described as an example for attracting ions, but a DC bias may also be applied by connecting a DC power supply. Note that a high-frequency bias may not be necessary depending on the characteristics of the plasma processing.

[0015] The gas supply mechanism 13 is for introducing gases such as plasma generation gas into the processing container 11, and has a plurality of gas introduction nozzles 41. The gas introduction nozzles 41 are provided on the top plate portion 21 of the processing container 11. Each gas introduction nozzle 41 is connected to a gas supply source 43 via a gas supply pipe 42. The gas supplied from the gas supply source 43 is, for example, a plasma generation gas such as Ar gas, or a raw material gas for film formation.

[0016] As described above, the microwave introduction device 15 is provided above the processing container 11 and functions as plasma generation means for introducing electromagnetic waves (microwaves) into the processing container 11 to generate plasma. The microwave introduction device 15 includes a top plate portion 21 of the processing container 11 that functions as a top plate, a microwave output unit 50 that generates microwaves and distributes and outputs the microwaves to a plurality of paths, and an antenna unit 51 that introduces the microwaves output from the microwave output unit 50 into the processing container 11.

[0017] The microwave output unit 50 includes a microwave power source (not shown), a microwave oscillator, an amplifier that amplifies the microwaves oscillated by the microwave oscillator, and a distributor that distributes the microwaves amplified by the amplifier to a plurality of paths. The microwave oscillator oscillates microwaves (for example, PLL oscillation) at, for example, 860 MHz. Note that the frequency of the microwaves is not limited to 860 MHz, and those in the range of 700 MHz to 10 GHz such as 2.45 GHz, 8.35 GHz, 5.8 GHz, 1.98 GHz, etc. can be used.

[0018] The antenna unit 51 includes a plurality of antenna modules (not shown), and each antenna module has an amplifier unit 52 that amplifies and outputs the microwaves from the microwave output unit 50, and a microwave radiation mechanism 53 that radiates the microwaves output from the amplifier unit 52 into the processing container 11.

[0019] Each microwave radiation mechanism 53 is provided on the top plate portion 21 and has a microwave transmission plate 54 that is exposed in the processing container 11. The microwave transmission plate 54 is made of a dielectric and has a shape (for example, a disc shape) that can efficiently radiate microwaves in the TE mode. The microwave radiation mechanisms 53 are arranged, for example, at the center of the top plate portion 21 and at six locations equidistantly around it. Note that as the material constituting the microwave transmission plate 54, for example, quartz, ceramics, fluorine-based resins such as polytetrafluoroethylene resin, polyimide resin, etc. can be used.

[0020] And a plurality of gas introduction nozzles 41 of the gas supply mechanism 13 are arranged so as to surround the periphery of the central microwave transmission plate 54. More specifically, in the present embodiment, for example, 12 gas introduction nozzles 41 are provided on the top plate portion 21 so as to surround the periphery of the central microwave transmission plate 54 at equal intervals.

[0021] A gas supply hole 71 that opens into the processing container 11 is formed at the tip of the gas introduction nozzle 41. The gas from the gas supply source 43 is supplied to the gas supply hole 71 through the gas supply pipe 42 and the gas introduction nozzle 41, and is discharged into the processing container 11 from the gas supply hole 71.

[0022] In the plasma processing apparatus 1, further, a plasma probe device 80 is provided on the side wall 23 of the processing container 11. The plasma probe device 80 senses the plasma generated in the plasma generation space S1 above the mounting table 12 in the processing container 11. Based on the sensing result, for example, the plasma electron temperature and the plasma electron density can be calculated.

[0023] The plasma probe device 80 is connected to a monitor device 81 located outside the processing container 11 via a coaxial cable 82. The monitor device 81 has a signal oscillator and outputs a signal of a predetermined frequency oscillated by the signal oscillator. The signal is transmitted to the plasma probe device 80 via the coaxial cable 82 and is transmitted from the shield disk 104 at the tip of the plasma probe device 80 to the plasma in the processing container 11. The plasma probe device 80 detects the current value of the signal reflected from the plasma side with respect to the signal transmitted to the plasma side and sends it to the monitor device 81. The detected current value is sent from the monitor device 81 to a control unit 16 described later, and is analyzed (specifically, FTT (frequency) analysis) by the control unit 16. Thereby, the plasma electron temperature and the plasma electron density are calculated.

[0024] The plasma processing apparatus 1 configured as described above is provided with at least one control unit 16. The control unit 16 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various processes described herein. The control unit 16 may be configured to control each element of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, some or all of the control unit 16 may be included in the plasma processing apparatus 1. The control unit 16 may include a processing unit, a storage unit, and a communication interface. The control unit 16 is implemented, for example, by a computer. The processing unit may be configured to read a program from the storage unit that provides logic or routines that enable various control operations, and to perform various control operations by executing the read program. This program may be stored in the storage unit in advance, or it may be retrieved via a medium when needed. The retrieved program is stored in the storage unit and read from the storage unit and executed by the processing unit. The medium may be various storage media readable by a computer, or it may be a communication line connected to a communication interface. The storage medium may be temporary or non-temporary. The processing unit may be a CPU (Central Processing Unit), or it may be one or more circuits. The memory 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 device 1 via a communication line such as a LAN (Local Area Network).

[0025] <Example of processing using plasma processing device 1> An example of a process performed using the plasma processing device 1 will be described. First, a wafer W, supported by a transport arm of a transport mechanism located outside the plasma processing apparatus 1, is transported into the processing container 11 through an input / output port 24 that is opened by a gate valve 25. Subsequently, the wafer W is transferred from the transport arm to a lifting pin, and then placed on the mounting table 12 via the lifting pin. After the transfer of the wafer W from the transport arm to the lifting pin, the transport arm is retracted from inside the processing container 11, and the input / output port 24 is closed. Next, the inside of the processing container 11 is reduced to a predetermined vacuum level.

[0026] Subsequently, the wafer W is subjected to plasma treatment. Specifically, plasma generation gas and the like are supplied into the processing container 11 from the gas supply port 71. Microwaves are also output from the microwave output unit 50. The output microwaves propagate along the surface of the top plate portion 21 of the processing container 11 on the plasma generation space S1 side via the microwave radiation mechanism 53. Surface wave plasma is generated in the region directly below the top plate portion 21 by the electric field of the microwaves propagating as surface waves. This surface wave plasma is then applied to the wafer W.

[0027] <Plasma probe device 80> Figure 2 is a cross-sectional view showing a schematic configuration of the plasma probe device 80. Figure 3 is a partially enlarged view of Figure 2.

[0028] In this embodiment, the plasma probe device 80 is used attached to the side wall 23 of the processing vessel 11, and specifically, as shown in Figures 2 and 3, it is used by being inserted through a through hole 23a that penetrates the side wall 23. The plasma probe device 80 includes a probe body 101, an electrode 102, a probe cover 103, and a shield disk 104 as a metal plate.

[0029] The probe body 101 is a rod-shaped component, specifically made of a metal material, i.e., a conductive material, and for example, its cross-sectional shape in an axial view is circular, i.e., it is formed in a cylindrical shape. The "axial direction" refers to the direction in which the plasma probe device 80 and the probe body 101 extend, which is the left-right direction in the figure. When the probe body 101 is formed in a cylindrical shape, its diameter is, for example, 5 to 10 mm. The plasma probe device 80 is mounted so that the probe body 101 penetrates the side wall 23 of the processing container 11. A flange 101a is provided on the outer circumference of the base end of the probe body 101. The flange 101a is used to fix the probe body 101 and the probe cover 103, as will be described later.

[0030] The electrode 102 transmits signals from the monitoring device 81 to the probe body 101. When the signal from the monitoring device 81 is transmitted, the monitoring device 81 detects the current that flows through the shield disk 104 and the probe body 101 to the plasma in the processing container 11. This electrode 102 is connected, for example, to the base end of the probe body 101.

[0031] The probe cover 103 covers the probe body 101 so as to electrically insulate it from the side wall 23 of the processing container 11. The probe cover 103 has an insulating cover 110 and a metal cover 120.

[0032] The insulating cover 110 is a cylindrical (specifically, for example, cylindrical) member made of an electrically insulating material. The probe body 101 is installed inside the insulating cover 110. The insulating cover 110 includes a first insulating cover 111 and a second insulating cover 112.

[0033] The first insulating cover 111 is a cylindrical (specifically, for example, cylindrical) member formed from an electrically insulating material with relatively high heat resistance (specifically, a ceramic such as alumina). When the first insulating cover 111 is formed in a cylindrical shape, the outer diameter of the tip of the insulating cover 110 is, for example, 8 to 12 mm. The first insulating cover 111 covers the tip side of the probe body 101. The tip surface of the first insulating cover 111 is exposed to the plasma generation space S1 side of the processing container 11. For example, the tip surface of the first insulating cover 111 and the tip surface of the metal cover 120 coincide without any step between them. The first insulating cover 111 has a flange 111a on the outer circumference of the base end side.

[0034] The second insulating cover 112 is a cylindrical (specifically, for example, cylindrical) member made of an electrically insulating material (specifically, a fluororesin) that has relatively low heat resistance but does not easily generate particles. The second insulating cover 112 covers the base end side of the probe body 101 beyond the portion covered by the first insulating cover 111. The tip surface of the second insulating cover 112 abuts against the base end surface of the first insulating cover 111. The second insulating cover 112 has a flange 112a on its outer circumference at the base end side.

[0035] The probe body 101 is fixed to the insulating cover 110 by sandwiching the flange 101a of the probe body 101 between the flange cover 113, which is provided on the base end side of the flange 112a, and the flange 112a. The flange cover 113 is formed in an annular shape with a hole 113a in the center, for example, using the same electrically insulating material as the second insulating cover 112. At least one of the electrode 102 and the probe body 101 is inserted through the hole 113a.

[0036] The metal cover 120 is a cylindrical (specifically, for example, cylindrical) member formed from a metal material with higher rigidity than the insulating cover 110. When the metal cover 120 is formed in a cylindrical shape, its outer diameter is 15 to 25 mm. The insulating cover 110 is provided inside the metal cover 120. For example, the metal cover 120 covers the entire first insulating cover 111 and the entire portion of the second insulating cover 112 from the flange 112a to the tip. The tip surface of the metal cover 120 is exposed to the plasma generation space S1 side of the processing vessel 11. For example, the tip surface of the metal cover 120 and the inner circumferential surface of the processing vessel 11 are on the same side without any step difference between them. The metal cover 120 has a butt portion 120a on the inner circumference at the tip side and a flange 120b on the outer circumference at the base end side.

[0037] The insulating cover 110 is fixed to the metal cover 120 by sandwiching the first insulating cover 111, the second insulating cover 112, and the flange cover 113 between the base end cover 121, which is provided on the base end side of the flange 120b, and the abutment portion 120a. Also, by sandwiching them as described above, the flange 101a of the probe body 101 is sandwiched between the flange 112a of the second insulating cover 112 and the flange cover 113, thereby fixing the probe body 101 to the insulating cover 110. In other words, the probe body 101 is fixed to the probe cover 103 via the flange 101a by sandwiching the first insulating cover 111, the second insulating cover 112, and the flange cover 113 between the base end cover 121 and the abutment portion 120a.

[0038] The shield disk 104 is connected to the tip of the probe body 101. In this example, the shield disk 104 is provided separately from the probe body 101. The shield disk 104 has a circular disc portion 104a in an axial view and a protrusion 104b extending from the center of the base end side surface of the disc portion 104a toward the base end. For example, the shield disk 104 is physically and electrically connected to the tip of the probe body 101 by screwing the recess 101b provided at the tip of the probe body 101 with the protrusion 104b.

[0039] Furthermore, the shield disk 104 covers the tip of the probe cover 103. Specifically, the shield disk 104 is located within the plasma generation space S1 when the plasma probe device 80 is attached to the side wall 23 of the processing vessel 11. The shield disk 104 covers the tip of the probe cover 103 with a gap K between it and the tip of the probe cover 103, so that the shield disk 104 and the side wall 23 of the processing vessel 11 do not conduct electricity through the probe cover 103. The gap K is formed at least between the base side surface, i.e., the back surface, of the shield disk 104 and the tip surface of the metal cover 120, and in this example, it is also formed between the back surface of the shield disk 104 and the tip of the insulating cover 110 (specifically the first insulating cover 111).

[0040] Furthermore, in this example, the outer circumference of the shield disk 104, when viewed axially, is located outside the outer circumference of the metal cover 120 (specifically, the outer circumference of the tip of the metal cover 120). In other words, the diameter of the disc portion 104a of the shield disk 104 is larger than the outer diameter of the tip of the annular metal cover 120, for example, 35 mm to 45 mm. Therefore, in this example, the disc portion 104a of the shield disk 104 covers the entire tip of the metal cover 120 and the tip of the insulating cover 110 (specifically, the tip of the first insulating cover 111).

[0041] In an axial view, the outer circumference of the shield disk 104 is located outside the outer circumference of the metal cover 120, and therefore outside the periphery of the through hole 23a, which is approximately the same as the outer circumference of the metal cover 120. For this reason, the plasma probe device 80 cannot be attached to the side wall 23 of the processing container 11 when the shield disk 104 is attached. When attaching to the side wall 23, the plasma probe device 80 without the shield disk 104 attached is first inserted through the through hole 23a of the side wall 23 from the first insulating cover 111 side, and then the shield disk 104 is attached to the tip of the probe body 101.

[0042] Furthermore, the plasma probe device 80 has a gas outlet 201 that supplies gas to the space S2 created by the gap K between the shield disk 104 and the tip of the probe cover 103. In an axial view, the gas outlet 201 is located on the probe body 101 side, i.e., inward, from the peripheral edge of the probe cover 103 (specifically, the outer peripheral edge of the tip of the probe cover 103). The gas from the outlet 201 prevents conductive materials such as metal in the processing gas in the plasma generation space S1 from accumulating on the tip of the insulating cover 110, and prevents the shield disk 104 or probe body 101 from becoming electrically conductive with the side wall 23 of the processing container 11 due to the accumulation of these materials.

[0043] The discharge port 201 is formed in an annular shape, for example, surrounding the probe body 101 in an axial view. Alternatively, multiple discharge ports 201 may be provided, arranged in an annular shape along the periphery of the probe body 101 in an axial view.

[0044] Furthermore, the gas from the discharge port 201 is discharged from the discharge port 201 so that it spreads radially around the probe body 101 in an axial view within space S2. Specifically, the gas is discharged axially from the discharge port 201 located on the probe cover 103 side toward the shield disk 104, collides with the base end side of the shield disk 104, and then moves toward the peripheral edge of the shield disk 104. Therefore, the gas from the discharge port 201 spreads radially around the probe body 101 in an axial view.

[0045] In this example, a discharge port 201 and a flow path 202 for guiding gas to the discharge port 201 are formed between the insulating cover 110 and the probe body 101. That is, the discharge port 201 and the flow path 202 are formed by the outer circumferential surface of the probe body 101 and the inner circumferential surface of the insulating cover 110. Specifically, the discharge port 201 is formed between the first insulating cover 111 and the probe body 101, and the flow path 202 is formed between the first insulating cover 111 and the second insulating cover 112 and the probe body 101.

[0046] The flow path 202 is connected to the gas supply source 212 via a flow path (not shown) formed within the base end cover 121 and a gas supply pipe 211. The gas supplied from the gas supply source 212 is supplied to the discharge port 201 via the gas supply pipe 211 and the flow path 202. After being discharged from the discharge port 201, the gas flows outward along the shield disk 104 in an axial view through the space S2 created by the gap K between the shield disk 104 and the probe cover 103, and is discharged from the peripheral edge of the shield disk 104 into the plasma generation space S1.

[0047] By the way, the ratio C / C0 of the concentration of the processing gas at the outermost position P of the insulating cover 110 in the axial view of space S2 to the concentration of the processing gas at the outermost position P0 of the shield disk 104 in the axial view of space S2 is expressed by the following formula. C / C0 = exp(-uL / D)

[0048] Here, u is the gas flow velocity from the discharge port 201 (m / s), L is the distance from the outermost position P0 to the outermost position P (m), and D is the gas type-dependent diffusion coefficient of the gas from the discharge port 201 (m 2 ( / s)

[0049] By setting the Peclet coefficient (uL / D) to 10 or higher, the C / C0 ratio can be reduced to 0.001% or less, thereby lowering the concentration of the processing gas at the outermost position P of the insulating cover 110 in an axial view, and further suppressing the accumulation of conductive materials such as metal in the processing gas at the tip of the insulating cover 110.

[0050] Therefore, the probe cover 103, probe body 101, shield disc 104, and discharge port 201 may be provided (i.e., designed) such that the Peclet number is 10 or more at the outermost part in the axial view within space S2. Specifically, both the design of the probe cover 103, probe body 101, shield disc 104, and discharge port 201, and the setting of the gas flow velocity from the discharge port 201 may be performed so that the Peclet number is 10 or more at the outermost part in the axial view within space S2.

[0051] Furthermore, if it is necessary to keep the gas flow rate from the discharge port 201 within a predetermined range due to equipment performance or other reasons, the following may be done. In other words, when the gas flow velocity from the discharge port 201 is within a predetermined range, the probe cover 103, probe body 101, shield disc 104, and discharge port 201 may be arranged such that the Peclet number is 10 or more at the outermost part in the axial view within the space S2.

[0052] The plasma probe device 80, configured as described above, senses the plasma in the plasma generation space S1 while the plasma processing device 1 is performing plasma processing on the wafer W. Furthermore, while the plasma processing device 1 is performing plasma processing on the wafer W, gas is discharged from the discharge port 201 of the plasma probe device 80, regardless of whether or not the plasma characteristics are being measured using the plasma probe device 80.

[0053] <Main effects of this embodiment> As described above, in this embodiment, the plasma probe device 80 includes a probe cover 103 which includes a cylindrical metal cover 120 and a cylindrical insulating cover 110 provided inside the metal cover 120, and a rod-shaped probe body 101 provided inside the insulating cover 110. The plasma probe device 80 also further includes a shielding disk 104 which is connected to the tip of the probe body 101 and covers the tip of the probe cover 103. Therefore, it is possible to suppress the exposure of the tip of the probe cover 103, including the insulating cover 110, to conductive materials (e.g., metal) contained in the processing gas in the plasma generation space S1. Furthermore, the plasma probe device 80 has a gas outlet 201 that supplies gas to the space S2 between the shielding disk 104 and the tip of the probe cover 103, located on the probe body 101 side, i.e., inward, from the peripheral end (outer edge) of the probe cover 103. Therefore, the gas discharged from the discharge port 201 flows through space S2 toward the peripheral edge of the shield disk 104, which prevents the processing gas in the plasma generation space S1 from entering space S2, for example, through the gap between the shield disk 104 and the inner surface of the side wall 23 of the processing container 11. Consequently, exposure of the tip of the probe cover 103, including the insulating cover 110, to conductive materials contained in the processing gas can be further suppressed. Thus, the formation of deposits of conductive material on the tip of the insulating cover 110 can be suppressed, and leakage of the current flowing through the probe body 101 to the side wall 23 of the processing container 11 through these deposits can be suppressed, allowing the plasma probe device 80 to accurately measure the characteristics of the plasma in the plasma generation space S1.

[0054] Furthermore, according to this embodiment, the gap between the shield disk 104 and the metal cover 120, and the gap between the shield disk 104 and the side wall 23 of the processing container 11, can be prevented from being filled with conductive material in the processing gas by the gas from the discharge port 201. Therefore, the leakage of the current flowing through the probe body 101 to the side wall 23 of the processing container 11 through the material filling the gaps can be prevented, and from this viewpoint as well, the characteristics of the plasma in the plasma generation space S1 can be accurately measured.

[0055] Furthermore, according to this embodiment, the surface area of ​​the shield disk 104, which is exposed to plasma and through which plasma-induced current flows, can be increased without increasing the size of the through-hole 23a through which the plasma probe device 80 is inserted. As a result, the signal-to-noise ratio of the current detected by the plasma probe device 80 can be improved. Furthermore, increasing the size of the through-hole 23a would necessitate increasing the size of the plasma probe device 80, which would worsen the ease of mounting the plasma probe device 80. In this embodiment, however, to improve the signal-to-noise ratio of the detected current, it is not necessary to increase the size of the through-hole 23a, as described above. Therefore, the signal-to-noise ratio of the detected plasma-induced current can be improved while maintaining the size and ease of mounting of the plasma probe device 80.

[0056] <Other examples of gas outlets> Figure 4 is a schematic cross-sectional view illustrating the configuration of a plasma probe device to illustrate another example of a gas outlet. Figure 5 is a partially enlarged view of Figure 4.

[0057] In the plasma probe device 80 shown in Figure 2, a gas outlet 201 and a flow path 202 for guiding gas to the outlet 201 were formed between the insulating cover 110 and the probe body 101. In contrast, in the plasma probe device 80A shown in Figures 4 and 5, a gas outlet 201A and a flow path 202A for guiding gas to the outlet 201A are formed between the insulating cover 110A and the metal cover 120A. That is, the gas outlet 201A and the flow path 202A for guiding gas to the outlet 201A are formed by the outer circumferential surface of the insulating cover 110A (specifically the first insulating cover 111A described later) and the inner circumferential surface of the metal cover 120A.

[0058] The plasma probe device 80A will be described in more detail below.

[0059] The plasma probe device 80A includes a probe body 101A, an electrode 102A, a probe cover 103A, and a shielding disk 104A as a metal plate.

[0060] The probe body 101A is a rod-shaped component, similar to the probe body 101 described above. If the probe body 101A is cylindrical, its diameter is, for example, 5 to 10 mm. The probe body 101A is fixed within the probe cover 103A by, for example, a fit, specifically by a fit with the second insulating cover 112A described later.

[0061] The function of electrode 102A is the same as that of electrode 102.

[0062] The probe cover 103A, like the probe cover 103, covers the probe body 101A so as to electrically insulate it from the side wall 23 of the processing container 11. The probe cover 103A has an insulating cover 110A and a metal cover 120A.

[0063] The insulating cover 110A is a cylindrical (specifically, for example, cylindrical) component made of an electrically insulating material. The probe body 101A is installed inside the insulating cover 110A. The insulating cover 110A includes a first insulating cover 111A and a second insulating cover 112A.

[0064] The first insulating cover 111A is a cylindrical (specifically, for example, cylindrical) member formed from an electrically insulating material with relatively high heat resistance (specifically, a ceramic such as alumina). When the first insulating cover 111A is formed in a cylindrical shape, the outer diameter of the tip of the first insulating cover 111A is, for example, 10 to 18 mm. The first insulating cover 111A covers substantially the entire probe body 101A, and specifically covers the entire second insulating cover 112A that covers the probe body 101A. The tip surface of the first insulating cover 111A is exposed to the plasma generation space S1 side of the processing container 11. The first insulating cover 111A has a flange 111Aa on the outer circumference of the base end side.

[0065] The second insulating cover 112A is a cylindrical (specifically, for example, cylindrical) component formed from an electrically insulating material (specifically, a fluororesin) that has relatively low heat resistance but does not easily generate particles. When the second insulating cover 112A is formed in a cylindrical shape, the outer diameter of the tip of the second insulating cover 112A is, for example, 8 to 16 mm. The second insulating cover 112A is installed inside the first insulating cover 111A and covers substantially the entire probe body 101A. The tip surface of the second insulating cover 112A is exposed to the plasma generation space S1 side of the processing container 11. The second insulating cover 112A is fixed inside the first insulating cover 111A by fitting together with the first insulating cover 111A.

[0066] The metal cover 120A is a cylindrical (specifically, for example, cylindrical) member formed from a metal material with higher rigidity than the insulating cover 110A. When the metal cover 120A is formed in a cylindrical shape, the outer diameter of the tip of the metal cover 120A is, for example, 15 to 25 mm. The insulating cover 110A is provided inside the metal cover 120A. For example, the metal cover 120A covers the entire insulating cover 110A. The tip surface of the metal cover 120A is exposed to the plasma generation space S1 side of the processing vessel 11. The metal cover 120A has a flange 120Ab on the outer circumference of the base end side.

[0067] The first insulating cover 111A is fixed to the metal cover 120A by sandwiching the flange 111Aa and flange cover 113A of the first insulating cover 111A between the base end cover 121A, which is provided on the base end side of the flange 120Ab, and the flange 120Ab. The flange cover 113A is formed in an annular shape with a hole 113Aa in the center, for example, using the same electrically insulating material as the second insulating cover 112A. At least one of the electrode 102A and the probe body 101A is inserted through the hole 113Aa.

[0068] The shield disk 104A is connected to the tip of the probe body 101A. In this example, the shield disk 104A is provided integrally with the probe body 101, thereby physically and electrically connecting to the tip of the probe body 101A. The shield disk 104A is formed in the shape of a circular disc when viewed in the axial direction.

[0069] Furthermore, the shield disk 104A covers the tip of the probe cover 103A. Specifically, the shield disk 104A is located within the plasma generation space S1 when the plasma probe device 80A is attached to the side wall 23 of the processing vessel 11. The shield disk 104A covers the tip of the probe cover 103A, with a gap K between it and the tip of the probe cover 103A.

[0070] Furthermore, in this example, the outer circumference of the shielding disk 104A, when viewed axially, is located inside the outer circumference of the metal cover 120A (specifically, the outer circumference of the tip of the metal cover 120A) and outside the inner circumference of the metal cover 120A (specifically, the inner circumference of the tip of the metal cover 120A). In other words, the diameter of the disc-shaped shielding disk 104A is smaller than the outer diameter of the tip of the annular metal cover 120A, and larger than the inner diameter. That is, the diameter of the disc-shaped shielding disk 104A is slightly smaller than the outer diameter of the tip of the cylindrical metal cover 120A. Therefore, in this example, the shielding disk 104A covers the entire tip of the insulating cover 110A and a portion of the tip of the metal cover 120A.

[0071] In an axial view, the outer circumference of the shield disk 104A is located inward from the outer circumference of the metal cover 120A, and therefore is located inward from the periphery of the through hole 23a, which is approximately coincident with the outer circumference of the metal cover 120A. For this reason, unlike the plasma probe device 80, the plasma probe device 80A can be mounted on the side wall 23 of the processing container 11 with the shield disk 104A installed.

[0072] Furthermore, the plasma probe device 80A has a gas outlet 201A that supplies gas to the space S2 formed by the gap K between the shield disk 104A and the tip of the probe cover 103A. In an axial view, the gas outlet 201A is located on the probe body 101A side, i.e., inward, from the peripheral edge of the probe cover 103A (specifically, the outer peripheral edge of the tip of the probe cover 103A).

[0073] The discharge port 201A is formed in an annular shape, for example, in an axial view, so as to surround the probe body 101A.

[0074] In this example, as described above, the discharge port 201A and the flow path 202A that guides gas to the discharge port 201A are formed between the insulating cover 110A and the metal cover 120A.

[0075] The flow path 202A is connected to the gas supply source 212 via a flow path (not shown) formed in, for example, the flange 120Ab and the gas supply pipe 211. The gas supplied from the gas supply source 212 is supplied to the discharge port 201A via the gas supply pipe 211 and the flow path 202A. After being discharged from the discharge port 201A, it flows outward along the shield disk 104A in an axial view through the space S2 created by the gap K between the shield disk 104A and the probe cover 103A, and is discharged from the peripheral edge of the shield disk 104A into the plasma generation space S1.

[0076] In this example, the plasma probe device 80A also prevents the tip of the probe cover 103A, including the insulating cover 110A, from being exposed to conductive materials (e.g., metals) contained in the processing gas within the plasma generation space S1 by covering the tip of the probe cover 103A with the shielding disk 104A. Furthermore, the gas discharged from the discharge port 201A further prevents the tip of the probe cover 103A, including the insulating cover 110A, from being exposed to conductive materials contained in the processing gas. Therefore, the formation of deposits of conductive material on the tip of the insulating cover 110A can be suppressed, and the leakage of current flowing through the probe body 101A to the side wall 23 of the processing container 11 through these deposits can be suppressed. As a result, the plasma characteristics within the plasma generation space S1 can be accurately measured using the plasma probe device 80A.

[0077] Furthermore, the plasma probe device 80A in this example also prevents the gap between the shield disk 104A and the metal cover 120A from being filled with conductive material in the processing gas. Therefore, it is possible to prevent the current flowing through the probe body 101A from leaking to the side wall 23 of the processing container 11 through the material filling the gap, and from this viewpoint as well, the characteristics of the plasma in the plasma generation space S1 can be accurately measured.

[0078] Furthermore, unlike the plasma probe device 80, the plasma probe device 80A does not require the shield disk 104A to be removed when attaching it to the side wall 23 of the processing vessel 11, thus improving ease of installation. In addition, the plasma probe device 80A has a larger surface area of ​​the part exposed to plasma and through which plasma-induced current flows compared to the case where the shield disk 104A is omitted. Therefore, the signal-to-noise ratio of the current detected by the plasma probe device 80 can be improved. Therefore, the plasma probe device 80A can improve both the ease of attachment to the side wall 23 of the processing vessel 11 and the signal-to-noise ratio of the detected plasma-induced current.

[0079] Furthermore, in the plasma probe device 80A, the diameter of the disc-shaped shield disk 104A is smaller than the outer diameter of the tip of the annular metal cover 120A. Therefore, when the plasma probe device 80A is attached to the side wall 23 of the processing container 11, the shield disk 104A is less likely to collide with the through hole 23a of the side wall 23. Consequently, damage to the base of the first insulating cover 111A due to this collision can be suppressed.

[0080] <Other variations> In the above example, there was one plasma probe device installed in the processing container 11, but there may be multiple devices. In the above example, the plasma probe device was provided on the side wall 23 of the processing vessel 11. However, the plasma probe device may also be provided on a component exposed to the internal space of the processing vessel 11, other than the side wall 23 of the processing vessel 11, i.e., a component exposed to plasma. For example, the plasma probe device may be provided on the top plate portion 21 of the processing vessel 11, or on the periphery of the mounting base 12. If provided on the periphery of the mounting base 12, components corresponding to the shield disks 104 and 104A are provided so as to be located above the mounting base 12.

[0081] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the constituent elements of the embodiments described above can be combined in any way. Such any combination will naturally yield the functions and effects of each constituent element in the combination, as well as other functions and effects that will be apparent to those skilled in the art from the description herein.

[0082] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that are obvious to those skilled in the art from the description herein, in addition to or instead of the effects described herein.

[0083] Furthermore, the following configuration examples also fall within the technical scope of this disclosure. (1) A plasma probe device provided on a member exposed to the internal space side of a processing vessel where plasma is generated, A probe cover including a cylindrical metal cover and a cylindrical insulating cover provided inside the metal cover, A rod-shaped probe body provided inside the insulating cover, It has a metal plate connected to the tip of the probe body and covering the tip of the probe cover, A plasma probe device having a gas outlet for supplying gas to the space between the metal plate and the tip of the probe cover, located on the probe body side from the peripheral edge of the probe cover. (2) The probe body has a circular cross-sectional shape when viewed in the axial direction, The plasma probe apparatus according to (1), wherein the discharge port is formed in an annular shape so as to surround the probe body when viewed in the axial direction. (3) The plasma probe apparatus according to (1) or (2), wherein the gas is discharged from the discharge port in such a way that it spreads radially around the probe body in an axial view within the space. (4) The plasma probe apparatus according to any one of (1) to (3), wherein the discharge port and the flow path for guiding the gas to the discharge port are formed between the metal cover and the insulating cover. (5) The plasma probe apparatus according to any one of (1) to (3), wherein the discharge port and the flow path for guiding the gas to the discharge port are formed between the insulating cover and the probe body. (6) The plasma probe apparatus according to any one of (1) to (5), wherein the probe cover, the probe body, the metal plate, and the discharge port are provided in the space such that the Pecle number is 10 or more at the outermost part of the insulating cover in an axial view. (7) The plasma probe apparatus according to any one of (1) to (6), wherein, in an axial view, the outermost circumference of the metal plate is located inside the outermost circumference of the metal cover and outside the innermost circumference of the metal cover. (8) A plasma processing apparatus comprising the plasma probe device described in any one of (1) to (7) above. [Explanation of Symbols]

[0084] 11 Processing container 23 Side wall 80, 80A Plasma Probe Device 101, 101A Probe Body 103, 103A Probe Cover 104, 104A Shielded Disc 110, 110A Insulation Cover 201, 201A discharge port P Outermost position P0 Outermost position S1 Plasma generation space S2 space W wafer

Claims

1. A plasma probe device provided on a member exposed to the internal space side of a processing vessel where plasma is generated, A probe cover including a cylindrical metal cover and a cylindrical insulating cover provided inside the metal cover, A rod-shaped probe body provided inside the insulating cover, It has a metal plate connected to the tip of the probe body and covering the tip of the probe cover, A plasma probe device having a gas outlet for supplying gas to the space between the metal plate and the tip of the probe cover, located on the probe body side from the peripheral edge of the probe cover.

2. The probe body has a circular cross-sectional shape when viewed in the axial direction. The plasma probe device according to claim 1, wherein the discharge port is formed in an annular shape so as to surround the probe body when viewed in the axial direction.

3. The plasma probe apparatus according to claim 1 or 2, wherein the gas is discharged from the discharge port so as to spread radially around the probe body in an axial view within the space.

4. The plasma probe apparatus according to claim 1 or 2, wherein the discharge port and the flow path for guiding the gas to the discharge port are formed between the metal cover and the insulating cover.

5. The plasma probe apparatus according to claim 1 or 2, wherein the discharge port and the flow path for guiding the gas to the discharge port are formed between the insulating cover and the probe body.

6. The plasma probe apparatus according to claim 1 or 2, wherein the probe cover, the probe body, the metal plate, and the discharge port are provided in such a way that the Peclet number is 10 or more at the outermost periphery of the insulating cover in an axial view within the space.

7. The plasma probe apparatus according to claim 1 or 2, wherein, in an axial view, the outermost circumference of the metal plate is located inside the outermost circumference of the metal cover and outside the innermost circumference of the metal cover.

8. A plasma processing apparatus comprising the plasma probe device according to claim 1 or 2.

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