Vacuum exhaust device and plasma generating device

Abstract

Provided is a vacuum exhaust device that is easily reduced in size. A vacuum exhaust device is provided with a turbo molecular pump and a plasma generation device (210). The plasma generation device (210) has a displaceable electrode (214); during non-operation in which no plasma is generated, the electrode (214) can be displaced to close the plasma communication port (228). A supply pipe for a raw material gas for generating plasma is connected to the plasma generation device (210), and the raw material gas is used for displacement of the electrode (214). The plasma generating device (210) is provided with a piston (220), and the electrode (214) is displaced by a pressure difference acting on the piston (220).

Description

Technical Field

[0001] The present invention relates to a vacuum exhaust device including a vacuum pump such as a turbomolecular pump, and a plasma generating device that can be combined with the vacuum pump. Background Art

[0002] Generally speaking, a type of vacuum pump is known as a turbomolecular pump. These pumps are used, for example, to exhaust air from semiconductor and flat-panel manufacturing equipment. In a turbomolecular pump, power to a motor within the pump body causes the rotating blades to rotate, ejecting gas molecules (gas molecules) drawn into the pump body (process gas). Furthermore, some turbomolecular pumps are equipped with heaters and cooling tubes to properly manage the temperature within the pump.

[0003] In vacuum pumps such as turbomolecular pumps, reaction products generated during the manufacturing process of semiconductors, etc., sometimes accumulate inside the vacuum pump. Patent Document 1, described below, discloses a technique for installing a plasma generator in the vacuum pump and performing plasma cleaning on the inside as a countermeasure against reaction products.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-017864 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] In the invention disclosed in Patent Document 1, the plasma source is provided via a valve to an inlet port provided on the side of the vacuum pump. As a result, the vacuum exhaust device, which is a combination of the vacuum pump and the plasma generator, may have a larger overall projecting dimension.

[0009] On the other hand, the vacuum pump may be surrounded by an actuator for a diverter valve connected to the vacuum pump's air intake, various piping, and a frame. In such cases, there may not be enough space around the vacuum pump to install a plasma generator. Furthermore, installing a plasma generator may require extensive modifications to the vacuum pump and its surroundings.

[0010] An object of the present invention is to provide a vacuum exhaust device and a plasma generating device that can be easily miniaturized.

[0011] Means used to solve technical problems

[0012] (1) In order to achieve the above-mentioned object, the vacuum exhaust device of the present invention is a vacuum exhaust device comprising a vacuum pump and a plasma generating device, characterized in that the aforementioned plasma generating device has a displaceable electrode; when not in operation and no plasma is generated, the aforementioned electrode can be displaced to close the plasma communication port.

[0013] (2) To achieve the above-mentioned object, the plasma generating device according to the present invention is characterized by comprising a displaceable electrode for generating plasma and for sealing a plasma communication port.

[0014] Effects of the Invention

[0015] According to the above invention, it is possible to provide a vacuum exhaust device and a plasma generating device that can be easily miniaturized. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is an explanatory diagram schematically showing the structure of a vacuum exhaust device according to the first embodiment of the present invention.

[0017] Figure 2 This is a circuit diagram showing an amplifier circuit.

[0018] Figure 3 This is a timing chart showing control when the current command value is larger than the detected value.

[0019] Figure 4 This is a timing chart showing control when the current command value is smaller than the detected value.

[0020] Figure 5 This is an explanatory diagram showing an enlarged view of the plasma generation device and its surroundings according to the first embodiment.

[0021] Figure 6 This is an explanatory diagram schematically showing the flow of power supply to the plasma generation device.

[0022] Figure 7 It is a block diagram schematically showing a supply line of a raw material gas.

[0023] Figure 8 (a) is an explanatory diagram showing the state of the plasma generating device when the turbomolecular pump is operating. Figure 8 (b) is an explanatory diagram showing the state of the plasma generating device when the turbomolecular pump is on standby.

[0024] Figure 9 It is an explanatory diagram showing a modified example including a connecting plate.

[0025] Figure 10 (a) is an explanatory diagram showing an enlarged view of a plasma generating apparatus and its surroundings according to a second embodiment of the present invention. Figure 10 (b) is an explanatory diagram showing an enlarged view of the plasma generation device and its surroundings according to the third embodiment of the present invention. DETAILED DESCRIPTION

[0026] <Basic Structure of Vacuum Exhaust Device 10 According to First Embodiment>

[0027] Figure 1 The following shows a vacuum exhaust device 10 according to a first embodiment of the present invention. The vacuum exhaust device 10 includes a turbomolecular pump 100, which is a vacuum pump, and a plasma generator 210. Details will be described later, but the turbomolecular pump 100 performs vacuum exhaust, and the plasma generator 210 performs plasma cleaning on reaction products generated by the turbomolecular pump 100.

[0028] More specifically, the vacuum exhaust device 10 has at least three operating modes (operating modes 1 to 3). Operating mode 1 is the normal operating mode. During normal operation in the normal operating mode, the turbomolecular pump 100 operates at the rated speed, and the plasma generator 210 is in the plasma cleaning off state (cleaning off state).

[0029] Operation mode 2 is a cleaning mode. During cleaning in the cleaning mode, the turbomolecular pump 100 is operated at a low speed or stopped (operation stop). The plasma generator 210 is in a plasma cleaning ON state (cleaning ON state).

[0030] Operation mode 3 is a standby mode. In standby mode, the turbomolecular pump 100 is in a low-speed operation or stopped (operation stop) state, similar to operation mode 2. The plasma generator 210 is in a plasma cleaning off state (cleaning off state), similar to operation mode 1.

[0031] In this embodiment, the term "non-operating" is sometimes used. Regarding the vacuum exhaust device 10, the state in which plasma is not generated is referred to as "non-operating." The aforementioned operating modes 1 and 3 are included in "non-operating." In contrast, the state in which plasma is generated can be referred to as "operating." The aforementioned operating mode 2 is included in "operating." The operation of the plasma generating device 210 in each operating mode (particularly during cleaning and standby) will be described later.

[0032] <Turbomolecular pump 100>

[0033] Figure 1 A turbomolecular pump 100 as a vacuum pump according to a first embodiment of the present invention is shown. The turbomolecular pump 100 is connected to a vacuum chamber (not shown) of target equipment such as a semiconductor manufacturing apparatus.

[0034] exist Figure 1 : A longitudinal sectional view of the turbo molecular pump 100 is shown in FIG. Figure 1 In the present invention, a turbomolecular pump 100 has an air intake port 101 formed at the upper end of a cylindrical outer cylinder 127. Furthermore, a rotor 103 is provided inside outer cylinder 127. Multiple rotating blades 102 (102a, 102b, 102c, etc.) are radially arranged in multiple stages around the circumference of the rotor 103, serving as turbine blades for sucking and exhausting gas. A rotor shaft 113 is mounted at the center of the rotor 103. This rotor shaft 113 is suspended in mid-air and positionally controlled by, for example, a five-axis magnetic bearing.

[0035] The upper radial electromagnets 104 are four electromagnets arranged in pairs along the X and Y axes. Four upper radial sensors 107 are provided adjacent to and corresponding to the upper radial electromagnets 104. The upper radial sensors 107 employ, for example, an inductance sensor or eddy current sensor having a conductive coil. They detect the position of the rotor shaft 113 based on changes in the inductance of the conductive coil that vary with the position of the rotor shaft 113. These upper radial sensors 107 are configured to detect radial displacement of the rotor shaft 113, i.e., the rotating body 103 fixed thereto, and transmit this information to the control device 200.

[0036] In the control device 200, for example, a compensation circuit having a PID adjustment function generates an excitation control command signal for the upper radial electromagnet 104 based on a position signal detected by the upper radial sensor 107. Figure 2 The amplifier circuit 150 (described later) controls the excitation of the upper radial electromagnet 104 based on the excitation control command signal, thereby adjusting the upper radial position of the rotor shaft 113 .

[0037] Furthermore, the rotor shaft 113 is formed from a high-permeability material (such as iron or stainless steel) and is attracted by the magnetic force of the upper radial electromagnet 104. This adjustment is performed independently in the X-axis and Y-axis directions. Furthermore, the lower radial electromagnet 105 and lower radial sensor 108 are arranged similarly to the upper radial electromagnet 104 and upper radial sensor 107, and the lower radial position of the rotor shaft 113 is adjusted in the same manner as the upper radial position.

[0038] Furthermore, axial electromagnets 106A and 106B are arranged so as to sandwich a disc-shaped metal disk (also called an "armature disk") 111 mounted on the lower portion of rotor shaft 113. Metal disk 111 is made of a high-permeability material such as iron. An axial sensor 109 is provided to detect axial displacement of rotor shaft 113, and its axial position signal is transmitted to control device 200.

[0039] Moreover, in the control device 200, for example, a compensation circuit having a PID adjustment function generates excitation control command signals for the axial electromagnet 106A and the axial electromagnet 106B based on the axial position signal detected by the axial sensor 109, and the amplifier circuit 150 performs excitation control on the axial electromagnet 106A and the axial electromagnet 106B based on these excitation control command signals. The axial electromagnet 106A attracts the metal disk 111 upward by magnetic force, and the axial electromagnet 106B attracts the metal disk 111 downward, thereby adjusting the axial position of the rotor shaft 113.

[0040] In this way, the control device 200 appropriately adjusts the magnetic force exerted on the metal disk 111 by the axial electromagnets 106A and 106B, magnetically levitating the rotor shaft 113 in the axial direction and maintaining it in space without contact. The amplifier circuit 150 that controls the excitation of the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B will be described later.

[0041] Meanwhile, motor 121 includes a plurality of magnetic poles arranged circumferentially to surround rotor shaft 113. Each magnetic pole is controlled by control device 200 to rotationally drive rotor shaft 113 via electromagnetic forces acting between the magnetic poles and rotor shaft 113. Furthermore, a rotational speed sensor (not shown) such as a Hall effect element, resolver, or encoder is incorporated into motor 121, and the rotational speed of rotor shaft 113 is detected based on detection signals from the rotational speed sensor.

[0042] Furthermore, a phase sensor (not shown) is mounted near the lower radial sensor 108, for example, to detect the rotation phase of the rotor shaft 113. The control device 200 detects the position of the magnetic pole using detection signals from the phase sensor and the rotation speed sensor simultaneously.

[0043] A plurality of stationary blades 123 (123a, 123b, 123c, ...) are arranged with slight gaps (predetermined intervals) between the rotating blades 102 (102a, 102b, 102c, ...). The rotating blades 102 (102a, 102b, 102c, ...) are formed to be inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to move exhaust gas molecules downward through collision.

[0044] Furthermore, the stationary blades 123 are similarly formed to be inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged toward the inside of the outer cylinder 127, staggered relative to the levels of the rotating blades 102. Furthermore, the outer peripheral ends of the stationary blades 123 are supported by being inserted between a plurality of stacked stationary blade spacers 125 (125a, 125b, 125c, ...).

[0045] The fixed blade spacer 125 is an annular member made of a metal such as aluminum, iron, stainless steel, copper, or an alloy containing these metals. An outer cylinder 127 is secured to the outer periphery of the fixed blade spacer 125 with a slight gap therebetween. A base 129 is provided at the bottom of the outer cylinder 127. An exhaust port 133 is formed in the base 129 and communicates with the outside. Exhaust gas entering the air intake port 101 from the chamber (vacuum chamber) side and transferred to the base 129 is then transported to the exhaust port 133.

[0046] Furthermore, depending on the application of the turbomolecular pump 100, a threaded spacer 131 is provided between the lower portion of the fixed blade spacer 125 and the base portion 129. The threaded spacer 131 is a cylindrical component made of a metal such as aluminum, copper, stainless steel, iron, or an alloy containing these metals, and has a plurality of spiral thread grooves 131a engraved on its inner circumference. The spiral direction of the thread grooves 131a is the direction in which the molecules of the exhaust gas are transferred toward the exhaust port 133 when they move in the rotation direction of the rotor 103. A rotating body lower cylindrical portion 103b is vertically provided at the lower portion of the rotating body main body 103a of the rotating body 103, where the rotating blades 102 (102a, 102b, 102c...) are formed. The outer circumference of the rotor lower cylindrical portion 103b is cylindrical and extends toward the inner circumference of the threaded spacer 131, remaining adjacent to the inner circumference of the threaded spacer 131 with a predetermined gap therebetween. Exhaust gas, transferred to the thread groove 131a by the rotating blades 102 and the fixed blades 123, is guided by the thread groove 131a and transported toward the base portion 129. Thus, the threaded spacer 131 and the rotor lower cylindrical portion 103b facing it constitute a Holweck exhaust mechanism 204. The Holweck exhaust mechanism 204 imparts directionality to the exhaust gas by the rotation of the rotor lower cylindrical portion 103b relative to the threaded spacer 131, thereby improving the exhaust characteristics of the turbomolecular pump 100.

[0047] The base 129 is a disc-shaped component that forms the base of the turbomolecular pump 100 and is generally made of a metal such as iron, aluminum, or stainless steel. Since the base 129 physically holds the turbomolecular pump 100 and also serves as a heat conduction path, a rigid metal such as iron, aluminum, or copper with high thermal conductivity is preferably used.

[0048] In this structure, when the rotary blades 102 and the rotor shaft 113 are rotated together by the motor 121, the exhaust gas is drawn from the chamber through the air intake port 101 by the action of the rotary blades 102 and the stationary blades 123. The exhaust gas drawn in through the air intake port 101 passes between the rotary blades 102 and the stationary blades 123 and is transferred to the base portion 129. At this time, the temperature of the rotary blades 102 rises due to frictional heat generated when the exhaust gas contacts the rotary blades 102 and heat conducted by the motor 121. However, this heat is transferred to the stationary blades 123 by radiation or conduction through gas molecules (gas molecules) of the exhaust gas.

[0049] The stationary blade spacers 125 are joined to each other at their outer circumferences, and transfer heat received by the stationary blades 123 from the rotary blades 102 , frictional heat generated when exhaust gas contacts the stationary blades 123 , and the like to the outside.

[0050] In the above description, it is assumed that the threaded spacer 131 is disposed on the outer periphery of the rotating body lower cylindrical portion 103b of the rotating body 103, and the threaded groove 131a is engraved on the inner peripheral surface of the threaded spacer 131. However, there is also a case where the threaded groove is engraved on the outer peripheral surface of the rotating body lower cylindrical portion 103b, and a spacer having a cylindrical inner peripheral surface is disposed around the threaded groove.

[0051] In addition, depending on the purpose of the turbomolecular pump 100, there are also the following situations: the electrical components are covered with a stator column 122, and the inside of the stator column 122 is maintained at a specified pressure with a cleaning gas to prevent the gas sucked from the air intake port 101 from invading the electrical components composed of the upper radial electromagnet 104, the upper radial sensor 107, the motor 121, the lower radial electromagnet 105, the lower radial sensor 108, the axial electromagnets 106A, 106B, the axial sensor 109, etc.

[0052] In this case, a purge gas port (not shown) is provided on the base portion 129, and purge gas is introduced through this piping. The introduced purge gas is delivered to the exhaust port 133 through the gaps 134 between the protective bearing 120 and the rotor shaft 113, between the rotor and stator of the motor 121, and between the inner circumferential cylindrical portion of the rotor blade 102 (rotating body lower cylindrical portion 103b), the stator column 122, and the base portion 129.

[0053] Here, the turbomolecular pump 100 requires control based on the model and its unique parameters (e.g., characteristics corresponding to the model) that have been adjusted. To store these control parameters, the turbomolecular pump 100 includes an electronic circuit unit 141 within its main body. The electronic circuit unit 141 is composed of semiconductor memory such as an EEPROM, electronic components such as semiconductor elements for accessing it, and a substrate 143 for mounting these components. The electronic circuit unit 141 is housed below the rotational speed sensor (not shown) near the center of the base 129 that constitutes the lower portion of the turbomolecular pump 100, for example, and is sealed by an airtight bottom cover 145.

[0054] Incidentally, in semiconductor manufacturing processes, some process gases introduced into the chamber have the property of solidifying if their pressure exceeds a specified value or their temperature drops below a specified value. Inside the turbomolecular pump 100, the exhaust gas pressure is lowest at the intake port 101 and highest at the exhaust port 133. If the process gas pressure exceeds a specified value or its temperature drops below a specified value while being transferred from the intake port 101 to the exhaust port 133, the process gas solidifies and adheres to and accumulates inside the turbomolecular pump 100.

[0055] For example, when SiCl4 is used as a process gas in an Al etching device, it can be seen from the vapor pressure curve that when the vacuum is low (760 [torr] ~ 10 -2 When the pressure is high (about 20°C) and the temperature is low (about 20°C), solid products (such as AlCl3) precipitate and adhere to the interior of the turbomolecular pump 100. Therefore, if the precipitates of the process gas accumulate inside the turbomolecular pump 100, the accumulation narrows the pump flow path, causing a decrease in the performance of the turbomolecular pump 100. Furthermore, the aforementioned products solidify in the high-pressure areas near the exhaust port 133 and the threaded spacer 131, making them prone to adhesion.

[0056] Therefore, to address this issue, conventionally, a heater (not shown) and an annular water-cooling pipe 149 are wound around the outer periphery of the base portion 129, etc., and a temperature sensor (e.g., a thermistor) (not shown) is embedded in the base portion 129. Based on the signal from the temperature sensor, heating of the heater and cooling of the water-cooling pipe 149 are controlled (hereinafter referred to as a TMS, or Temperature Management System) to maintain the temperature of the base portion 129 at a constant, high temperature (set temperature). In this embodiment, a heater (not shown) embedded in the threaded spacer 131 heats the threaded spacer 131, and the base portion 129 is cooled by the water-cooling pipe 149 embedded in the bottom cover 145.

[0057] Next, the amplifier circuit 150 for controlling the excitation of the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B of the turbomolecular pump 100 thus constructed will be described. Figure 2 A circuit diagram of the amplifier circuit is shown in FIG.

[0058] exist Figure 2 In the example, the electromagnetic coil 151, which constitutes the upper radial electromagnet 104, has one end connected to the positive electrode 171a of the power supply 171 via the transistor 161, and the other end connected to the negative electrode 171b of the power supply 171 via the current detection circuit 181 and the transistor 162. Furthermore, the transistors 161 and 162 are so-called power MOSFETs, each having a diode connected between its source and drain.

[0059] At this time, transistor 161 has its diode cathode terminal 161a connected to anode 171a and its anode terminal 161b connected to one end of electromagnetic coil 151. In addition, transistor 162 has its diode cathode terminal 162a connected to current detection circuit 181 and its anode terminal 162b connected to cathode 171b.

[0060] On the other hand, the cathode terminal 165a of the current regeneration diode 165 is connected to one end of the electromagnetic coil 151, and the anode terminal 165b is connected to the negative electrode 171b. Similarly, the cathode terminal 166a of the current regeneration diode 166 is connected to the positive electrode 171a, and the anode terminal 166b is connected to the other end of the electromagnetic coil 151 via the current detection circuit 181. The current detection circuit 181 is composed of, for example, a Hall effect sensor and a resistor element.

[0061] The amplifier circuit 150 configured as described above corresponds to one electromagnet. Therefore, if the magnetic bearing is controlled in five axes and there are ten electromagnets (104, 105, 106A, 106B), a similar amplifier circuit 150 is configured for each electromagnet, and ten amplifier circuits 150 are connected in parallel to the power supply 171.

[0062] Furthermore, the amplifier control circuit 191 is constituted by, for example, a digital signal processor unit (hereinafter referred to as a DSP unit) not shown in the control device 200 , and switches the transistors 161 and 162 on and off.

[0063] Amplifier control circuit 191 compares the current value detected by current detection circuit 181 (a signal reflecting this current value is referred to as current detection signal 191c) with a predetermined current command value. Based on this comparison result, it determines the pulse width (pulse width times Tp1 and Tp2) generated within one cycle of PWM control, or control cycle Ts. Consequently, amplifier control circuit 191 outputs gate drive signals 191a and 191b having the corresponding pulse widths to the gate terminals of transistors 161 and 162.

[0064] Furthermore, when the rotational speed of the rotating body 103 passes through a resonance point during accelerated operation or when disturbances occur during constant speed operation, it is necessary to control the position of the rotating body 103 at high speed and with a strong force. Therefore, a high voltage of, for example, approximately 50V is used as the power supply 171 to enable a rapid increase (or decrease) in the current flowing to the electromagnet coil 151. Furthermore, a capacitor (not shown) is typically connected between the positive electrode 171a and the negative electrode 171b of the power supply 171 to stabilize the power supply 171.

[0065] In this configuration, when both transistors 161 and 162 are turned on, the current flowing through the electromagnetic coil 151 (hereinafter referred to as the electromagnetic current iL) increases, and when both transistors 161 and 162 are turned off, the electromagnetic current iL decreases.

[0066] Furthermore, by turning on one of transistors 161 and 162 and turning off the other, a so-called freewheeling current is maintained. By allowing this freewheeling current to flow through amplifier circuit 150, hysteresis losses in amplifier circuit 150 can be reduced, keeping the power consumption of the entire circuit low. Furthermore, by controlling transistors 161 and 162 in this manner, high-frequency noise such as harmonics generated in turbomolecular pump 100 can be reduced. Furthermore, by measuring this freewheeling current with current detection circuit 181, the electromagnet current iL flowing through electromagnet coil 151 can be detected.

[0067] That is, when the detected current value is smaller than the current command value, Figure 3 As shown, transistors 161 and 162 are both turned on only once during a control cycle Ts (e.g., 100 μs) for a time period corresponding to pulse width Tp1. Therefore, during this period, electromagnet current iL increases toward current value iLmax (not shown), which allows it to flow from positive electrode 171a to negative electrode 171b via transistors 161 and 162.

[0068] On the other hand, when the detected current value is larger than the current command value, as shown in FIG. Figure 4As shown, transistors 161 and 162 are both turned off only once in the control cycle Ts for a time period corresponding to the pulse width time Tp2. Therefore, during this period, the electromagnet current iL decreases toward a current value iLmin (not shown) that can be regenerated from the negative electrode 171b to the positive electrode 171a via the diodes 165 and 166.

[0069] In either case, after the pulse width time Tp1 or Tp2 has elapsed, one of the transistors 161 and 162 is turned on. Therefore, during this period, a current continues to flow through the amplifier circuit 150.

[0070] The turbomolecular pump 100 having such a basic structure Figure 1 The upper side (the side of the air inlet 101) becomes the air inlet connected to the target device, and the lower side (the side of the base 129 provided with the exhaust port 133 connected to the exhaust port 135 protruding to the left in the figure) becomes the exhaust part connected to the auxiliary pump (boosting pump) etc. not shown in the figure. Figure 1 In addition to the vertical posture in the vertical direction as shown, it can also be used in an inverted posture, a horizontal posture, and an inclined posture.

[0071] In the turbomolecular pump 100, the outer cylinder 127 and the base 129 are combined to form a housing (hereinafter, the two will be collectively referred to as the "main body housing"). Furthermore, the turbomolecular pump 100 is electrically (and structurally) connected to a box-shaped electrical equipment housing (not shown), which houses the control device 200.

[0072] The internal structure of the main housing of the turbomolecular pump 100 (the combination of the outer cylinder 127 and the base 129) can be divided into a rotating mechanism, which rotates the rotor shaft 113 and other components via the motor 121, and an exhaust mechanism, which is rotationally driven by the rotating mechanism. Furthermore, the exhaust mechanism can be considered to be a turbomolecular pump mechanism consisting of the rotating vanes 102, the stationary vanes 123, and the like, and a threaded groove pump mechanism (Holweck-type exhaust mechanism) consisting of the lower cylindrical portion of the rotor 103b, the threaded spacer 131, and the like.

[0073] The aforementioned cleaning gas (shielding gas) is used to protect the bearings and the rotor blades 102, prevent corrosion caused by the exhaust gas (process gas), and cool the rotor blades 102. The cleaning gas can be supplied by a common method.

[0074] For example, the purge gas port 132 is provided at a predetermined position (e.g., 90 degrees, 120 degrees, etc.) of the base portion 129, extending linearly in the radial direction. Purge gas is supplied to the purge gas port 132 from outside the base portion 129 via a purge gas tank (e.g., an N2 gas tank), a flow regulator (valve device), and the like.

[0075] The aforementioned protection bearing 120 is also referred to as a "safety (T / D) bearing" or "backing bearing." These protection bearings 120 prevent the position and orientation of the rotor shaft 113 from significantly changing even in the event of a fault such as an electrical system failure or atmospheric intrusion, thereby preventing damage to the rotor blades 102 and their surroundings.

[0076] In addition, in the structure of the turbomolecular pump 100 and the rotating body 103, Figure 1 In order to avoid complicating the drawings, the description of hatching indicating the cross-section of the parts is omitted.

[0077] <Basic Structure of Plasma Generator 210>

[0078] As mentioned above, there are cases where products are accumulated inside the turbomolecular pump 100. In this embodiment, Figure 5 The plasma generation device 210 shown in (a) performs cleaning of products.

[0079] The plasma generating device 210 includes an electrode 214, an insulating spacer 216, a movable shaft 218, and a piston 220 in a cylinder 212. The cylinder 212 is formed by processing metal such as aluminum or stainless steel into a cylindrical shape having steps on the outer and inner circumferences.

[0080] Cylinder 212 is secured to support surface 127a of outer cylinder 127 of turbomolecular pump 100 using multiple (e.g., six) hexagonal bolts 222. Support surface 127a is flat. An O-ring 224 hermetically seals the cylinder 212 and outer cylinder 127. Cylinder 212 is secured to support surface 127a of outer cylinder 127 in a manner that allows heat transfer between the cylinder 212 and outer cylinder 127.

[0081] In the axial direction of the cylinder 212 ( Figure 5 (a) The two ends of the left and right directions) are formed with openings 212a and 212b. One side ( Figure 5 The opening 212a on the right side of (a) is closed by a cover 226. The cover 226 is fixed to the cylinder 212 by a plurality of (eg, six) hexagonal bolts 227.

[0082] The other side ( Figure 5The opening 212b on the left side of (a) is spatially connected to the opening 127b formed in the outer cylinder 127 of the turbomolecular pump 100. The opening 212b of the cylinder 212 and the opening 127b of the outer cylinder 127 form a plasma communication port 228 for introducing plasma from the plasma generating device 210 into the turbomolecular pump 100.

[0083] In this embodiment, the plasma communication port 228 opens toward the boundary portion of the turbomolecular pump mechanism portion and the thread groove pump mechanism portion (Holweck type exhaust mechanism portion 204), the turbomolecular pump mechanism portion is composed of rotating blades 102, fixed blades 123, etc., and the thread groove pump mechanism portion is composed of the lower cylindrical portion 103b of the rotating body, the threaded spacer 131, etc.

[0084] The electrode 214 is formed into a disk shape inside the cylinder 212. The electrode 214 is fixed concentrically to the front end of the movable shaft 218 ( Figure 5 (a) The end on the left side, the end on the turbomolecular pump 100 side.) As the material of the electrode 214, various materials known as materials for plasma electrodes and the like can be used.

[0085] The movable shaft 218 is formed into a stepped cylindrical shape and is inserted into the cylindrical insulating spacer 216. The axial middle portion of the movable shaft 218 is inserted into the inner side of the insulating spacer 216. The movable shaft 218 is made of a metal such as aluminum or stainless steel.

[0086] The insulating spacer 216 is processed into a cylindrical shape having a flange portion 216a and is disposed concentrically with the cylinder 212 within the cylinder 212. The insulating spacer 216 is made of a material having electrical insulation properties (eg, insulating resin).

[0087] Hexagonal bolts 232 are inserted into flange 216a of insulating spacer 216. Hexagonal bolts 232 are screwed into cylinder 212, and insulating spacer 216 is fixed to cylinder 212 by hexagonal bolts 232. An O-ring 234 hermetically seals the spacer 216 and cylinder 212.

[0088] A raw material gas introduction groove 236 is formed over the entire outer peripheral surface of the insulating spacer 216. The raw material gas introduction groove 236 is used to flow the raw material gas used to generate plasma, and the structure for displacing the electrode 214 will be described later.

[0089] At the rear end portion of the movable shaft 218 ( Figure 5The right end of the piston (a), opposite to the turbomolecular pump 100, is concentrically fixed to the piston 220 via a hexagonal nut 238. The piston 220 is cylindrical and has a head 220a. The piston 220 is made of an electrically insulating material (e.g., an insulating resin). The function of the piston 220 will be described later.

[0090] The piston 220 and the movable shaft 218 are hermetically sealed by an O-ring 235 . The piston 220 and the cylinder 212 are hermetically sealed by an O-ring 237 . The movable shaft 218 and the insulating spacer 216 are hermetically sealed by an O-ring 239 .

[0091] Electrode 214, movable shaft 218, and piston 220 are integrated to form a conductive movable body 240. Movable body 240 is supported by insulating spacer 216 and is axially movable. Movable body 240 is displaceable relative to insulating spacer 216 (and cylinder 212).

[0092] Figure 5 (a) shows that the movable body 240 moves backward (toward Figure 5 (a) is displaced to the right) and the electrode 214 interferes with the insulating spacer 216. In this state, the electrode 214 is separated from the support surface 127a of the outer cylinder 127. Figure 5 (b) shows that the movable body 240 moves forward (towards Figure 5 (b) The electrode 214 interferes with the support surface 127a of the outer cylinder 127 and the plasma communication port 228 is closed.

[0093] The displacement of the movable shaft 218 and the electrode 214 is controlled by the difference in internal pressure among the first chamber 242, the second chamber 244, and the third chamber 246 formed in the cylinder 212. Figure 5 (a) Figure 5 As shown in (b), the first chamber 242 is the space where the electrode 214 is located. The second chamber 244 is the space defined by the flange 216a of the insulating spacer 216 and the head 220a of the piston 220. The third chamber 246 is the space defined by the piston 220 and the cover 226.

[0094] The cylinder 212 is provided with one first gas supply passage 248 and one second gas supply passage 250. The first gas supply passage 248 and the second gas supply passage 250 are passages formed to extend in the radial direction of the cylinder 212 and have a circular cross section.

[0095] The first gas supply passage 248 opens toward the raw gas introduction groove 236 formed on the outer peripheral surface of the insulating spacer 216 and is spatially connected to the raw gas introduction groove 236. The area between the raw gas introduction groove 236 and the first chamber 242 is not hermetically sealed, and the raw gas introduction groove 236 and the first chamber 242 are spatially connected. In this embodiment, the area between the raw gas introduction groove 236 and the first chamber 242 forms a throttle portion 252 that narrows the flow path along the entire circumference of the insulating spacer 216.

[0096] The second gas supply passage 250 opens toward the second chamber 244. The second gas supply passage 250 and the second chamber 244 are spatially connected.

[0097] like Figure 5 As shown in (a), the hexagonal nut 238 that fixes the piston 220 to the movable shaft 218 has an annular crimping terminal 254 sandwiched between it and the piston 220. The crimping terminal 254 is electrically connected to the electrode 214 via the movable shaft 218. Figure 6 As schematically shown in FIG, a power source 256 is connected to the electrode 214, and a high voltage for plasma generation is applied from the power source 256 to the electrode 214. In this embodiment, the cylinder 212 is grounded.

[0098] <Structure for Displacing Electrode 214>

[0099] A raw material gas is supplied to first gas supply passage 248 and second gas supply passage 250. As the raw material gas, for example, a gas such as NF3 (nitrogen trifluoride) or CF4 (carbon tetrafluoride) is used. However, the present invention is not limited thereto; instead of the raw material gas, another gas (such as air) may be compressed and used to displace movable body 240.

[0100] Figure 7 The schematic diagram shows a supply line 258 for the raw material gas supplied to the first gas supply passage 248 and the second gas supply passage 250. The supply line 258 includes a gas tank 260, a pressure regulating valve 262, an on-off valve 264, a throttle 266, and supply pipes 267 and 269 (indicated by arrows).

[0101] Gas tank 260 supplies a source gas at a predetermined pressure (e.g., 10 MPa) toward plasma generator 210. Pressure regulating valve 262 reduces the pressure of the source gas. Pressure regulating valve 262 reduces the pressure of the source gas from, for example, 10 MPa to 0.1 MPa. On / off valve 264, for example, is a normally closed valve. When controlled to open, it opens the flow path and allows the source gas to pass through.

[0102] The source gas flow path is divided into two systems at a branch point 268 provided downstream of the on-off valve 264, and connected to the first gas supply path 248 and the second gas supply path 250 of the plasma generator 210. A throttle 266 is provided between the branch point 268 and the first gas supply path 248.

[0103] A known restrictor can be used as the restrictor 266. Although not shown in the figure, the restrictor 266 may have a structure in which a porous metal body (flow rate restriction portion) is built in to provide a predetermined piping resistance to the gas flow path.

[0104] In this embodiment, the throttle 266 creates a pressure difference between the inflow side and the outflow side and reduces the flow rate of the raw material gas of 0.1 [MPa] to, for example, 50 sccm (Standard Cubic Centimeter per Minute, 20°C or 0°C).

[0105] When the on-off valve 264 is opened, the low-pressure raw material gas is introduced into the first gas supply passage 248 after passing through the throttle 266. The raw material gas introduced into the first gas supply passage 248 is as follows: Figure 8 As indicated by arrow A in (a), the raw gas is introduced into the first chamber 242 through the insulating spacer 216 through the raw gas introduction groove 236 and the throttle portion 252 .

[0106] In the first chamber 242, the raw material gas flows from the back side to the front side of the electrode 214 and flows into the plasma communication port 228. Here, one side of the turbomolecular pump 100 is set as the front side of the electrode 214, and the opposite side is set as the back side of the electrode 214. The pressure of the raw material gas acts on the plate surfaces on the front and back sides of the electrode 214.

[0107] On the other hand, the source gas that has not passed through the throttle 266 (whose flow rate is not restricted) is introduced into the second gas supply passage 250. Hereinafter, the source gas introduced into the second gas supply passage 250 is referred to as "piston driving gas."

[0108] Since the piston driving gas does not pass through the throttle 266, it is higher pressure than the raw gas introduced into the first gas supply passage 248 through the throttle 266. The second gas supply passage 250 is connected to the second chamber 244. Figure 8 As indicated by arrow B in (a), the liquid is introduced into the second chamber 244 .

[0109] The head 220a of the piston 220 faces the second chamber 244. Therefore, the piston driving gas acts on the plate surface 220b on one side of the head 220a (plate surface on the turbomolecular pump 100 side), and the piston 220 receives a force from the piston driving gas.

[0110] The force of the piston driving gas acts on the piston 220 in a direction away from the turbomolecular pump 100. Therefore, the piston 220 is pushed away from the turbomolecular pump 100, and the movable body 240 moves toward Figure 8 The right side of (a) moves back in a straight line.

[0111] like Figure 5 (a) and Figure 8 As shown in (a), when the movable body 240 moves backward and the electrode 214 interferes with the insulating spacer 216, the movable body 240 stops. In this way, the insulating spacer 216 functions as a stopper when the movable body 240 moves backward.

[0112] When the on-off valve 264 is closed, the supply of raw gas via the raw gas supply line 258 is not performed. Furthermore, the piston driving gas is not supplied to the second chamber 244, and the raw gas is supplied only to the turbomolecular pump 100. Furthermore, the aforementioned auxiliary pump (boosting pump) exhausts (roughly evacuates) the interior of the turbomolecular pump 100. This roughing prevents process gas and the like from accumulating within the turbomolecular pump 100 and causing chemical reactions or corrosion. As a result, the pressures in the first chamber 242 and the second chamber 244 are equalized.

[0113] On the other hand, the third chamber 246 is not sealed from the outside air, and the pressure in the third chamber 246 is equal to the atmospheric pressure. Furthermore, the pressures in the first chamber 242 and the second chamber 244 are roughly pumped by the auxiliary pump (boosting pump) mentioned above, and are lower than the pressure (atmospheric pressure) in the third chamber 246. As a result, Figure 8 As shown by arrow P in (b), the piston 220 is pushed toward the side close to the turbomolecular pump 100, and the movable body 240 moves toward Figure 8 (b) Go straight to the left.

[0114] like Figure 5 (b) and Figure 8 As shown in (b), when the movable body 240 moves forward and the electrode 214 interferes with the outer cylinder 127 of the turbomolecular pump 100, the movable body 240 stops. In this way, the outer cylinder 127 of the turbomolecular pump 100 functions as a stopper when the movable body 240 moves forward.

[0115] When the electrode 214 interferes with the outer cylinder 127 of the turbomolecular pump 100, the electrode 214 comes into surface contact with the outer cylinder 127. Therefore, the plasma communication port 228 is closed (blocked) by the electrode 214, and the spatial connection between the turbomolecular pump 100 and the plasma generating device 210 is cut off.

[0116] In the vacuum exhaust device 10 having such a structure, when the turbomolecular pump 100 is cleaned (in the case of the aforementioned operation mode 2), the on-off valve 264 ( Figure 7 ) is set to on. Then, if Figure 5 (a) and Figure 8 As shown in (a), the source gas is supplied to the first gas supply passage 248 of the plasma generator 210, and the piston driving gas is supplied to the second gas supply passage 250. As a result, the electrode 214 retreats and separates from the outer cylinder 127 of the turbomolecular pump 100.

[0117] A voltage for plasma generation is applied to the electrode 214. The potential difference between the electrode 214 and the outer tube 127 and the potential difference between the electrode 214 and the cylinder 212 ionizes the raw material gas, generating atoms of radicals of the raw material gas.

[0118] In addition, when the turbomolecular pump 100 is in standby mode (in the case of the aforementioned operation mode 3), the on-off valve 264 ( Figure 7 ) is set to off, such as Figure 5 (b) and Figure 8 As shown in (b), the piston driving gas is not supplied to the second gas supply passage 250. Then, due to the pressure difference between the third chamber 246 and the second chamber 244, the electrode 214 moves forward, and the plasma communication port 228 is closed.

[0119] Here, the raw material gas supply line 258 may be a supply line included in the plasma generation device 210. The supply line 258 and the plasma generation device 210 may be collectively understood as, for example, a "plasma generation system."

[0120] <Advantages of Vacuum Exhaust Device 10>

[0121] According to the vacuum exhaust apparatus 10 described above, the plasma communication port 228 between the turbomolecular pump 100 and the plasma generator 210 can be opened and closed using the electrode 214 disposed within the cylinder 212 of the plasma generator 210. Furthermore, the mechanism for opening and closing the plasma communication port 228 can be integrated into the plasma generator 210. Consequently, the vacuum exhaust apparatus 10 can be miniaturized. Furthermore, the size of the vacuum exhaust apparatus 10 with a plasma cleaning function can be reduced, thereby preventing the installation location of the vacuum exhaust apparatus 10 from being restricted by its size.

[0122] Furthermore, according to the vacuum exhaust apparatus 10 , the supply of the raw material gas can be turned on and off by the on-off valve 264 , and the electrode 214 can be displaced by a simple mechanism.

[0123] Furthermore, the plasma generator 210 generates a high temperature by generating plasma. However, since the cylinder 212 is fixed in a state where it can conduct heat to the outer cylinder 127 of the turbomolecular pump 100 , the heat generated by the plasma generator 210 can be dissipated to the outer cylinder 127 of the turbomolecular pump 100 .

[0124] Furthermore, the vacuum exhaust device 10 can prevent the reaction products from accumulating inside the plasma generating device 210. Therefore, not only the inside of the turbomolecular pump 100 but also the inside of the plasma generating device 210 can be kept clean.

[0125] Furthermore, the electrode 214 is separated from the movable shaft 218 by removing the hexagonal nut 230. Therefore, the electrode 214 can be attached and detached, and the replacement of the electrode 214 is easy.

[0126] In addition, in this embodiment, the cylinder 212 is grounded, but is not limited to this. For example, the cover body 226 can also be formed with a conductive material, and a crimping terminal can be attached to a hexagonal bolt 227 that fixes the cover body 226 to be grounded through the cover body 226.

[0127] Furthermore, the plasma generator 210 can be assembled into the turbomolecular pump 100, with the vacuum exhaust device 10 positioned within the flow path (distribution path). This is not limiting; the plasma generator 210 can also be separated from the turbomolecular pump 100, with the plasma generator 210 and the turbomolecular pump 100 positioned independently within the flow path. When the turbomolecular pump 100 and the plasma generator 210 are moved separately, a cap (not shown) can be attached to the outer cylinder 127 of the turbomolecular pump 100 to close the opening 127b.

[0128] Furthermore, it is also possible to Figure 9 As shown in the modified example, the plasma generating device 210 is attached to the turbomolecular pump 100 via the connecting plate 280. Figure 9 In the example shown in FIG. 2 , an O-ring 282 is interposed between the connecting plate 280 and the outer cylinder 127 of the turbomolecular pump 100 , and the connecting plate 280 is tightly connected to the supporting surface 127 a of the outer cylinder 127 together with the cylinder 212 .

[0129] Figure 9 Arrow G indicates that the connecting plate 280 is fixed to the support surface 127a of the outer cylinder 127 together with the plasma generating device 210. Here, the connecting plate 280 may be included in the plasma generating device 210 as a part thereof.

[0130] The connecting plate 280 has a connecting hole 284 extending through the center of the plate in the thickness direction. The connecting hole 284 is sized to conceal the electrode 214 while exposing the distal end of the movable shaft 218. The connecting hole 284, along with the opening 127b of the outer tube 127 and the opening 212b of the cylinder 212, forms the plasma communication port 228.

[0131] By providing the connecting plate 280 in this manner, the electrode 214 can be hidden from exposure. Furthermore, by providing the connecting plate 280, it is no longer necessary to directly place the electrode 214 against the support surface 127a of the outer cylinder 127, and processing of the outer cylinder 127 becomes easier.

[0132] Specifically, when the connecting plate 280 is not provided, the support surface 127a of the outer cylinder 127 must be sufficiently large and processed to be flat (plane processing) in order to attach the plasma generating device 210 and maintain a constant distance from the electrode 214. Furthermore, the O-ring 282 must be larger than the outer dimensions of the electrode 214.

[0133] In contrast, when connecting plate 280 is provided, since electrode 214 faces connecting plate 280, the size of support surface 127a of outer cylinder 127 does not need to be adjusted to fit electrode 214. Furthermore, a smaller component can be used as O-ring 282. Furthermore, the area (area) of support surface 127a that needs to be flattened can be reduced. As a result, the area that needs to be flattened can be reduced to the minimum necessary. Furthermore, machining of outer cylinder 127, a relatively large component, is facilitated.

[0134] <Plasma Generator 310 According to Second Embodiment>

[0135] Figure 10 (a) shows a plasma generating device 310 and its surroundings of a vacuum exhaust device according to the second embodiment. In the description of the second embodiment, the same reference numerals are given to the same parts as those in the first embodiment, and their description is omitted as appropriate.

[0136] In the plasma generation device 310 according to the second embodiment, in order to displace the electrode 214, the piston 220 ( Figure 5 (a) etc.) and is provided with a diaphragm 370. The diaphragm 370 is attached to the cylinder 312 via a hexagonal bolt 327 so as to close the opening 312a of the cylinder 312.

[0137] Furthermore, the diaphragm 370 is concentrically fixed to the rear end portion ( Figure 10(a) The right end portion, the end portion opposite to the turbomolecular pump 100 ). Both plate surfaces of the diaphragm 370 face the outside of the second chamber 344 and the plasma generation device 310 .

[0138] In the second embodiment, when the turbomolecular pump 100 is cleaned (in the case of the aforementioned operation mode 2), the on-off valve 264 ( Figure 7 ) is turned on. Then, the raw material gas is supplied to the first gas supply passage 248 of the plasma generation device 310, and the piston driving gas is supplied to the second gas supply passage 250.

[0139] The diaphragm 370 is pushed toward the side away from the turbomolecular pump 100 by the piston driving gas in the second chamber 344, and the movable body 340 moves toward Figure 10 As a result, the electrode 214 retreats, as shown in FIG. Figure 10 As shown in (a), the electrode 214 is separated from the outer cylinder 127 of the turbomolecular pump 100 .

[0140] In addition, when the turbomolecular pump 100 is in standby mode (in the case of the aforementioned operation mode 3), the on-off valve 264 ( Figure 7 ) is set to OFF, and the piston driving gas is not supplied to the second gas supply passage 250. Furthermore, although not shown, the pressure difference between the atmospheric pressure outside air and the second chamber 344 causes the diaphragm 370 to be pushed toward the turbomolecular pump 100 and deformed, becoming a shape that protrudes toward the turbomolecular pump 100. As a result, the electrode 214 advances, and the plasma communication port 228 is closed.

[0141] According to the second embodiment, the same effects of the invention as those of the first embodiment can be achieved.

[0142] <Plasma Generator 410 According to Third Embodiment>

[0143] Figure 10 (b) shows a plasma generating device 410 and its surroundings of a vacuum exhaust device according to the third embodiment. In the description of the third embodiment, the same reference numerals are given to the same parts as those in the first embodiment, and their description is omitted as appropriate.

[0144] In the plasma generation device 410 according to the third embodiment, in order to displace the electrode 214, the piston 220 ( Figure 5 (a) etc.) and has a disk-shaped magnet target 420. The magnet target 420 is a magnetic body and is concentrically fixed to the rear end of the movable shaft 418 ( Figure 10 The right end of (b), the end opposite to the turbomolecular pump 100).

[0145] One side of the cylinder 412 ( Figure 10 The opening 412a on the right side of (b) is closed by the electromagnet holding case 426. The electromagnet holding case 426 is attached to the cylinder 412 via hexagonal bolts 427 so as to close the opening 412a of the cylinder 412.

[0146] Electromagnet holding box 426 holds electromagnet 470 inside. Electromagnet 470 can be a single ring-shaped structure or a combination of multiple arc-shaped electromagnets in a ring-shaped structure. Electromagnet 470 is positioned near the electromagnetic target. "Near" here means, for example, a position close enough to where sufficient magnetic force is applied to displace electrode 214.

[0147] A coil spring 472 is housed in the center of the inner side of the electromagnet holding box 426. One end of the coil spring 472 ( Figure 10 (b) The right end of the coil spring 472 abuts against the electromagnet holding box 426, and the other end of the coil spring 472 ( Figure 10 The left end portion of (b) abuts against the magnet target 420.

[0148] The cylinder 412 is not provided with the second gas supply passage 250 provided in the first and second embodiments, and the electrode 214 is displaced using the magnet target 420 and the electromagnet 470 .

[0149] In the third embodiment, when the turbomolecular pump 100 is cleaned (in the case of the aforementioned operation mode 2), the electromagnet 470 is turned on. The magnetic force of the electromagnet 470 acts on the magnetic target 420, and the magnetic target 420 is attracted by the electromagnet 470. The coil spring 472 is in a contracted state, and the magnetic target 420 interferes with the electromagnet holding box 426. The movable body 440 is as shown in FIG. Figure 10 As shown in (b), the electrode 214 is in the retracted position and is separated from the outer cylinder 127 of the turbomolecular pump 100 .

[0150] Furthermore, when the turbomolecular pump 100 is in standby mode (in the aforementioned operating mode 3), the electromagnet 470 is turned off, and the magnetic target 420 is released from the electromagnet 470. Although not shown, the coil spring 472 is in an extended state, and the magnetic target 420 moves toward the turbomolecular pump 100. As a result, the electrode 214 advances, and the plasma communication port 228 is closed.

[0151] The third embodiment can also achieve the same effects as those of the first embodiment. Furthermore, the second gas supply passage 250 is no longer necessary, and the raw material gas supply line 258 can be simplified.

[0152] <Inventions that can be extracted from each embodiment>

[0153] The following inventions can be extracted from the respective embodiments described above.

[0154] (1) A vacuum exhaust device (vacuum exhaust device 10, etc.) comprising a vacuum pump (turbo molecular pump 100, etc.) and a plasma generating device (plasma generating device 210, 310, 410, etc.), wherein the plasma generating device has a displaceable electrode (electrode 214, etc.); Figure 5 (b) shows a state where the plasma cleaning is turned off, where no high voltage is applied to the electrode and no raw material gas for generating plasma is supplied to the electrode side), and the aforementioned electrode can be displaced to close the plasma communication port (plasma communication port 228, etc.).

[0155] (2) The vacuum exhaust device described in (1) above is connected to the plasma generating device with supply pipes (supply pipes 267, 269, etc.) for the raw material gas used to generate plasma, and the raw material gas is used for displacement of the electrode.

[0156] (3) In the vacuum exhaust device described in (2) above, a piston (such as the piston 220) is provided on the electrode, and the electrode is displaced by the pressure difference acting on the piston.

[0157] (4) In the vacuum exhaust device described in (2) above, a diaphragm (diaphragm 370, etc.) is provided in the plasma generating device, and the pressure difference generated in the diaphragm causes the diaphragm to deform and the electrode to displace.

[0158] (5) The vacuum exhaust device as described in (1) above is provided in the plasma generating device with: an electromagnet target (magnet target 420, etc.) composed of a magnetic body; and an electromagnet (electromagnet 470, etc.) provided near the electromagnet target; so that the magnetic force generated between the electromagnet target and the electromagnet acts on the electrode, causing the electrode to displace.

[0159] (6) The vacuum exhaust device according to any one of (1) to (5) above, wherein the vacuum pump and the plasma generating device are fixed so that heat can be transferred from the plasma generating device to the vacuum pump.

[0160] (7) The vacuum exhaust device according to any one of (1) to (5) above is characterized in that the electrode is opposed to the housing (external cylinder 127, etc.) of the vacuum pump.

[0161] (8) A plasma generating device (plasma generating device 210, 310, 410, etc.) characterized by comprising a displaceable electrode (electrode 214, etc.) for generating plasma and for sealing a plasma communication port (plasma communication port 228, etc.).

[0162] <Other>

[0163] The present invention is not limited to the above-described embodiments, and various modifications and combinations of the embodiments are possible without departing from the spirit of the invention.

[0164] Description of Reference Numerals

[0165] 10: Vacuum exhaust device

[0166] 100: Turbomolecular pump

[0167] 127: Outer cylinder

[0168] 210, 310, 410: Plasma generating device

[0169] 212: Cylinder

[0170] 214: Electrode

[0171] 216: Insulating spacer

[0172] 218: Movable axis

[0173] 220: Piston

[0174] 226: Cover

[0175] 228: Plasma communication port

[0176] 240, 340, 440: Movable

[0177] 248: First gas supply path

[0178] 250: Second gas supply path

[0179] 267, 269: Supply piping

[0180] 370: Diaphragm

[0181] 420: Magnetic Target

[0182] 470: Electromagnet

Claims

1. A vacuum exhaust device comprising a vacuum pump and a plasma generating device, characterized in that: The plasma generating device has a displaceable electrode; During non-operation when plasma is not generated, the electrode can be displaced to close the plasma communication port.

2. The vacuum exhaust device according to claim 1, wherein: A supply pipe for a raw material gas for generating plasma is connected to the plasma generating device, and the raw material gas is used for displacement of the electrode.

3. The vacuum exhaust device according to claim 1, wherein: The plasma generating device is provided with a piston, and due to the pressure difference acting on the piston, the piston moves and the electrode is displaced.

4. The vacuum exhaust device according to claim 1, wherein: The plasma generating device is provided with a diaphragm, and due to the pressure difference generated in the diaphragm, the diaphragm is deformed and the electrode is displaced.

5. The vacuum exhaust device according to claim 1, wherein: The plasma generating device is provided with: an electromagnet target composed of a magnetic body; and an electromagnet disposed near the aforementioned electromagnet target; The magnetic force generated between the electromagnetic target and the electromagnet is caused to act on the electrode, thereby displacing the electrode.

6. The vacuum exhaust device according to any one of claims 1 to 5, wherein: The vacuum pump and the plasma generating device are fixed to each other so that heat can be transferred from the plasma generating device to the vacuum pump.

7. The vacuum exhaust device according to any one of claims 1 to 5, wherein: The electrode faces the housing of the vacuum pump.

8. A plasma generating device, characterized in that: A displaceable electrode is provided for generating plasma and sealing the plasma communication port.

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