Turbomolecular Pump

Abstract

To provide a turbomolecular pump in which a gas absorption object is arranged without increasing the axial length of an intake port due to the gas absorption object.SOLUTION: A turbomolecular pump comprises a rotor part and a stator part in a casing (outer cylinder 127). The turbomolecular pump comprises a getter pump part in the stator part or casing, and also comprises a heater part 402 that performs at least one of activation and regeneration of a gas adsorption object 401 in the getter pump part.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a turbomolecular pump. [Background technology]

[0002] One turbo molecular pump includes a getter pump section, which includes a meandering plate-like gas adsorbing metal section and a heater section in the hollow section of the intake port (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2-215977 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above turbomolecular pump, the meandering plate-like gas adsorbing metal part and the heater part are installed in the hollow part of the intake port, so the length of the intake port in the axial direction becomes large. And since the length of the intake port increases, the axial length of the above turbomolecular pump increases, so that it is difficult to adopt this structure when there is a restriction on the installation space.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide a turbomolecular pump in which a gas adsorbing material is arranged without increasing the length of the axial intake port due to the gas adsorbing material. [Means for solving the problem]

[0006] The turbomolecular pump of the present invention is a turbomolecular pump having a rotor section and a stator section within a casing, and is equipped with a getter pump section arranged in the stator section or the casing, and a heater section that performs at least one of activation and regeneration of gas-adsorbing material in the getter pump section.The gas adsorbing body may further include any one of the following configurations (A), (B) and (C): (A) A temperature sensor for controlling the temperature of the gas adsorbing body and a control device, the control device controls the temperature of the gas adsorbing body based on an output signal of the temperature sensor, the getter pump section is disposed in a stator section, the stator section includes multiple stages of fixed vanes and multiple stages of fixed vane spacers for positioning the multiple stages of fixed vanes, and the temperature sensor is disposed in the stator section; (B) A control device is further provided, the control device specifies a conductive current of the heater section and performs constant resistance control based on the conductive current to control the temperature of the gas adsorbing body; (C) A thermal resistance increasing means is further provided for increasing the thermal resistance between a first member on which the getter pump section is disposed and a second member adjacent to the first member compared to when the first member and the second member are in surface contact with each other. Effect of the Invention

[0007] According to the present invention, a turbomolecular pump in which a gas adsorbing material is disposed can be obtained without increasing the length of the intake port in the axial direction due to the gas adsorbing material.

[0008] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a vertical sectional view showing a turbomolecular pump as a vacuum pump according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a circuit diagram showing an amplifier circuit that controls excitation of the electromagnets of the turbo molecular pump shown in FIG. [Diagram 3] FIG. 3 is a time chart showing the control when the current command value is larger than the detection value. [Figure 4] FIG. 4 is a time chart showing the control when the current command value is smaller than the detection value. [Diagram 5] FIG. 5 is a cross-sectional view showing an example of a getter pump portion in the turbo molecular pump according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing an example of a getter pump portion in a turbo molecular pump according to the second embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing an example of a getter pump portion in a turbo molecular pump according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] Embodiment 1

[0012] A longitudinal cross-sectional view of this turbomolecular pump 100 is shown in Fig. 1. In Fig. 1, the turbomolecular pump 100 has an intake port 101 formed at the upper end of a cylindrical outer tube 127. Inside the outer tube 127, a rotor 103 is provided, the rotor 103 having a plurality of rotors 102 (102a, 102b, 102c, ...) which are turbine blades for sucking in and exhausting gas, formed radially on its periphery in multiple stages. A rotor shaft 113 is attached to the center of the rotor 103, and the rotor shaft 113 is supported in the air and position-controlled by, for example, a five-axis controlled magnetic bearing. The rotor 103 is generally made of a metal such as aluminum or an aluminum alloy.

[0013] The upper radial electromagnets 104 are arranged in pairs on the X-axis and the Y-axis. Four upper radial sensors 107 are provided adjacent to the upper radial electromagnets 104 and corresponding to each of the upper radial electromagnets 104. The upper radial sensors 107 are, for example, inductance sensors or eddy current sensors having conductive windings, and detect the position of the rotor shaft 113 based on the change in inductance of the conductive windings that changes according to the position of the rotor shaft 113. The upper radial sensors 107 are configured to detect the radial displacement of the rotor shaft 113, i.e., the rotating body 103 fixed thereto, and send the detected displacement to the control device 200.

[0014] In this 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, and an amplifier circuit 150 (described later) shown in Figure 2 controls the excitation of the upper radial electromagnet 104 based on this excitation control command signal, thereby adjusting the upper radial position of the rotor shaft 113.

[0015] The rotor shaft 113 is made of a material with high magnetic permeability (iron, stainless steel, etc.) and is attracted by the magnetic force of the upper radial electromagnet 104. Such adjustment is performed independently in the X-axis direction and the Y-axis direction. The lower radial electromagnet 105 and the lower radial sensor 108 are arranged in the same manner as the upper radial electromagnet 104 and the upper radial sensor 107, and adjust the lower radial position of the rotor shaft 113 in the same manner as the upper radial position.

[0016] Furthermore, axial electromagnets 106A and 106B are arranged above and below a circular metal disk 111 provided at the bottom of rotor shaft 113. Metal disk 111 is made of a high magnetic permeability material such as iron. An axial sensor 109 is provided to detect the axial displacement of rotor shaft 113, and an axial position signal is sent to control device 200.

[0017] In the control device 200, a compensation circuit having, for example, a PID adjustment function generates an excitation control command signal for each of the axial electromagnets 106A and 106B based on the axial position signal detected by the axial sensor 109, and the amplifier circuit 150 controls the excitation of the axial electromagnets 106A and 106B based on these excitation control command signals, so that 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.

[0018] In this way, the control device 200 appropriately adjusts the magnetic force that the axial electromagnets 106A, 106B exert on the metal disk 111, magnetically levitating the rotor shaft 113 in the axial direction and holding it in a non-contact manner in space. The amplifier circuit 150 that controls the excitation of the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A, 106B will be described later.

[0019] Meanwhile, motor 121 has a plurality of magnetic poles arranged circumferentially so as to surround rotor shaft 113. Each magnetic pole is controlled by control device 200 so as to rotate rotor shaft 113 via electromagnetic force acting between the magnetic pole and rotor shaft 113. Also, motor 121 incorporates a rotation speed sensor such as a Hall element, resolver, or encoder (not shown), and the rotation speed of rotor shaft 113 is detected by a detection signal from this rotation speed sensor.

[0020] Furthermore, for example, a phase sensor (not shown) is attached near the lower radial sensor 108 to detect the phase of rotation of the rotor shaft 113. The control device 200 detects the position of the magnetic poles using the detection signals of both this phase sensor and the rotation speed sensor.

[0021] A plurality of fixed blades 123 (123a, 123b, 123c...) are arranged with a small gap between the rotor blades 102 (102a, 102b, 102c...). The rotor blades 102 (102a, 102b, 102c...) are formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transport exhaust gas molecules downward through collision. The fixed blades 123 (123a, 123b, 123c...) are made of metal such as aluminum, iron, stainless steel, copper, or an alloy containing these metals as components.

[0022] Similarly, the fixed blades 123 are formed at an inclination at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged alternately with the stages of the rotor blades 102 toward the inside of the outer cylinder 127. The outer peripheral ends of the fixed blades 123 are supported in a state where they are inserted between a plurality of stacked stages of fixed blade spacers 125 (125a, 125b, 125c, etc.).

[0023] The fixed wing spacer 125 is a ring-shaped member and is made of metal such as aluminum, iron, stainless steel, copper, or an alloy containing these metals as components. An outer cylinder 127 is fixed to the outer periphery of the fixed wing spacer 125 with a small gap therebetween. A base portion 129 is disposed at the bottom of the outer cylinder 127. An exhaust port 133 is formed in the base portion 129 and communicates with the outside. Exhaust gas that enters the intake port 101 from the chamber (vacuum chamber) side and is transferred to the base portion 129 is sent to the exhaust port 133.

[0024] Furthermore, depending on the application of the turbo molecular pump 100, a threaded spacer 131 is disposed between the lower part of the fixed vane spacer 125 and the base part 129. The threaded spacer 131 is a cylindrical member made of a metal such as aluminum, copper, stainless steel, iron, or an alloy containing these metals, and has a plurality of helical thread grooves 131a engraved on its inner peripheral surface. The helical direction of the thread groove 131a is the direction in which, when the molecules of the exhaust gas move in the rotation direction of the rotor 103, the molecules are transferred toward the exhaust port 133. A cylindrical part 102d hangs down from the lowest part of the rotor 103, which is connected to the rotor vanes 102 (102a, 102b, 102c, etc.). The outer peripheral surface of this cylindrical part 102d is cylindrical and protrudes toward the inner peripheral surface of the threaded spacer 131, and is adjacent to the inner peripheral surface of the threaded spacer 131 with a predetermined gap therebetween. The exhaust gas transferred to the thread groove 131a by the rotor 102 and the fixed blade 123 is sent to the base portion 129 while being guided by the thread groove 131a.

[0025] The base portion 129 is a disk-shaped member that constitutes the base of the turbomolecular pump 100, and is generally made of metal such as iron, aluminum, stainless steel, etc. The base portion 129 physically holds the turbomolecular pump 100 and also functions as a heat conduction path, so it is desirable to use a metal that has rigidity and high thermal conductivity, such as iron, aluminum, or copper.

[0026] In this configuration, when the rotor 102 is rotated together with the rotor shaft 113 by the motor 121, the exhaust gas is sucked from the chamber through the intake port 101 by the action of the rotor 102 and the fixed blade 123. The rotation speed of the rotor 102 is usually 20,000 rpm to 90,000 rpm, and the peripheral speed at the tip of the rotor 102 reaches 200 m / s to 400 m / s. The exhaust gas sucked through the intake port 101 passes between the rotor 102 and the fixed blade 123 and is transferred to the base part 129. At this time, the temperature of the rotor 102 rises due to frictional heat generated when the exhaust gas comes into contact with the rotor 102 and conduction of heat generated by the motor 121, and the like, but this heat is transferred to the fixed blade 123 side by radiation or conduction by gas molecules of the exhaust gas, and the like.

[0027] The fixed blade spacers 125 are joined to each other at their outer peripheries, and transmit heat received by the fixed blades 123 from the rotor blades 102, frictional heat generated when exhaust gas comes into contact with the fixed blades 123, and the like to the outside.

[0028] In the above description, the threaded spacer 131 is disposed on the outer periphery of the cylindrical portion 102d of the rotor 103, and the thread groove 131a is formed on the inner periphery of the threaded spacer 131. However, there are also cases where the thread groove is formed on the outer periphery of the cylindrical portion 102d, and a spacer having a cylindrical inner periphery is disposed around the outer periphery of the cylindrical portion 102d.

[0029] Depending on the application of the turbomolecular pump 100, in order to prevent the gas sucked in from the intake port 101 from entering the electrical equipment section, which is 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 and 106B, the axial sensor 109, etc., the electrical equipment section may be covered all around with a stator column 122, and the inside of this stator column 122 may be kept at a predetermined pressure by a purge gas.

[0030] In this case, piping (not shown) is provided in the base portion 129, and purge gas is introduced through this piping. The introduced purge gas is sent to the exhaust port 133 through gaps between the protective bearing 120 and the rotor shaft 113, between the rotor and stator of the motor 121, and between the stator column 122 and the inner cylindrical portion of the rotor blades 102.

[0031] Here, the turbomolecular pump 100 requires control based on specific parameters (e.g., various characteristics corresponding to the model) that are individually adjusted and identified as a model. In order to store these control parameters, the turbomolecular pump 100 has an electronic circuit section 141 in its main body. The electronic circuit section 141 is composed of a semiconductor memory such as an EEPROM, electronic components such as semiconductor elements for accessing the memory, and a substrate 143 for mounting these components. The electronic circuit section 141 is housed below a rotational speed sensor (not shown) near the center of a base section 129 that constitutes the lower part of the turbomolecular pump 100, and is closed by an airtight bottom cover 145.

[0032] In the semiconductor manufacturing process, some process gases introduced into the chamber have the property of becoming solid when their pressure exceeds a predetermined value or their temperature falls below a predetermined value. Inside the turbo molecular pump 100, the pressure of the exhaust gas is lowest at the intake port 101 and highest at the exhaust port 133. If the pressure of the process gas becomes higher than a predetermined value or the temperature falls below a predetermined value while the process gas is being transferred from the intake port 101 to the exhaust port 133, the process gas becomes solid and adheres to and accumulates inside the turbo molecular pump 100.

[0033] For example, when SiCl4 is used as the process gas in an Al etching device, low vacuum (760[torr]~10 -2It can be seen from the vapor pressure curve that at a vapor pressure of 100 MPa (100 [torr]) and low temperature (approximately 20 [°C]), solid products (e.g., AlCl3) precipitate and adhere to and accumulate inside the turbomolecular pump 100. As a result, when precipitates of the process gas accumulate inside the turbomolecular pump 100, the deposits narrow the pump flow path, causing a decrease in the performance of the turbomolecular pump 100. The above-mentioned products are prone to solidification and adhesion in high-pressure areas near the exhaust port 133 and near the threaded spacer 131.

[0034] Therefore, in order to solve this problem, in the past, a heater (not shown) or a circular water-cooled tube 149 was wrapped around the outer periphery of the base portion 129, and a temperature sensor (e.g., a thermistor) (not shown) was embedded in the base portion 129, and the heating of the heater and the cooling by the water-cooled tube 149 were controlled based on the signal from this temperature sensor to keep the temperature of the base portion 129 at a constant high temperature (set temperature) (hereinafter referred to as TMS; Temperature Management System).

[0035] Next, regarding the turbo molecular pump 100 configured as described above, an amplifier circuit 150 that controls excitation of the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A and 106B will be described. A circuit diagram of this amplifier circuit 150 is shown in FIG.

[0036] 2, one end of an electromagnet winding 151 constituting the upper radial electromagnet 104 etc. is connected to a positive electrode 171a of a power source 171 via a transistor 161, and the other end is connected to a negative electrode 171b of the power source 171 via a current detection circuit 181 and a transistor 162. The transistors 161 and 162 are so-called power MOSFETs, and have a structure in which a diode is connected between the source and drain.

[0037] At this time, the transistor 161 has a cathode terminal 161a of the diode connected to the positive electrode 171a, and an anode terminal 161b connected to one end of the electromagnet winding 151. The transistor 162 has a cathode terminal 162a of the diode connected to the current detection circuit 181, and an anode terminal 162b connected to the negative electrode 171b.

[0038] On the other hand, the current regeneration diode 165 has its cathode terminal 165a connected to one end of the electromagnet winding 151 and its anode terminal 165b connected to the negative electrode 171b. Similarly, the current regeneration diode 166 has its cathode terminal 166a connected to the positive electrode 171a and its anode terminal 166b connected to the other end of the electromagnet winding 151 via a current detection circuit 181. The current detection circuit 181 is composed of, for example, a Hall sensor type current sensor or an electric resistance element.

[0039] The amplifier circuit 150 configured as above corresponds to one electromagnet. Therefore, when the magnetic bearing is controlled by five axes and there are a total of ten electromagnets 104, 105, 106A, and 106B, a similar amplifier circuit 150 is configured for each electromagnet, and the ten amplifier circuits 150 are connected in parallel to the power supply 171.

[0040] Furthermore, the amplifier control circuit 191 is configured, for example, by a digital signal processor section (hereinafter referred to as a DSP section) (not shown) of the control device 200, and this amplifier control circuit 191 switches the transistors 161 and 162 on / off.

[0041] The amplifier control circuit 191 is adapted to compare the current value detected by the current detection circuit 181 (a signal reflecting this current value is called a current detection signal 191c) with a predetermined current command value. Then, based on the result of this comparison, the magnitude of the pulse width (pulse width times Tp1, Tp2) to be generated within a control cycle Ts, which is one period of PWM control, is determined. As a result, gate drive signals 191a, 191b having this pulse width are output from the amplifier control circuit 191 to the gate terminals of the transistors 161, 162.

[0042] In addition, when the rotor 103 passes through a resonance point during an accelerating operation of the rotation speed, or when a disturbance occurs during a constant speed operation, it is necessary to control the position of the rotor 103 at high speed and with a strong force. For this reason, a high voltage of, for example, about 50 V is used as the power supply 171 so that the current flowing through the electromagnet winding 151 can be rapidly increased (or decreased). In addition, a capacitor (not shown) is usually connected between the positive pole 171a and the negative pole 171b of the power supply 171 to stabilize the power supply 171.

[0043] In this configuration, when both transistors 161, 162 are turned on, the current flowing through the electromagnet winding 151 (hereinafter referred to as electromagnet current iL) increases, and when both are turned off, the electromagnet current iL decreases.

[0044] Moreover, when one of the transistors 161, 162 is turned on and the other is turned off, a so-called flywheel current is maintained. By passing a flywheel current through the amplifier circuit 150 in this manner, the hysteresis loss in the amplifier circuit 150 can be reduced, and the power consumption of the entire circuit can be kept low. Furthermore, by controlling the transistors 161, 162 in this manner, high-frequency noise such as harmonics generated in the turbo molecular pump 100 can be reduced. Furthermore, by measuring this flywheel current with the current detection circuit 181, the electromagnet current iL flowing through the electromagnet winding 151 can be detected.

[0045] That is, when the detected current value is smaller than the current command value, both of the transistors 161 and 162 are turned on for a time period corresponding to the pulse width time Tp1 only once in a control cycle Ts (e.g., 100 μs) as shown in Fig. 3. Therefore, the electromagnet current iL during this period increases toward a current value iLmax (not shown) that can flow from the positive electrode 171a to the negative electrode 171b via the transistors 161 and 162.

[0046] On the other hand, when the detected current value is larger than the current command value, both of the transistors 161 and 162 are turned off for a time period corresponding to the pulse width time Tp2 only once during the control cycle Ts, as shown in Fig. 4. Therefore, the electromagnet current iL during this period decreases toward a current value iLmin (not shown) that can be regenerated from the negative pole 171b to the positive pole 171a via the diodes 165 and 166.

[0047] In either case, after the pulse width times Tp1 and Tp2 have elapsed, one of the transistors 161 and 162 is turned on. Therefore, a flywheel current is maintained in the amplifier circuit 150 during this period.

[0048] The turbomolecular pump 100 is configured as described above. Furthermore, in Fig. 1, the rotor 102 and rotor 103 are the rotor portion of the turbomolecular pump 100, the fixed vanes 123 and fixed vane spacer 125 are the stator portion of the turbomolecular pump portion 100, and the threaded spacer 131 is the stator portion of the threaded pump portion subsequent to the turbomolecular pump portion. Furthermore, the intake port 101 and outer cylinder 127 are the casing of the turbomolecular pump 100, and house the rotor portion and the multiple stator portions. The rotor portion is rotatably held within the casing, and the stator portion is disposed opposite the rotor portion.

[0049] Furthermore, the turbo molecular pump 100 shown in FIG. 1 includes a getter pump section disposed in the stator section or the casing, and a heater section that performs at least one of activation and regeneration of the gas adsorbing substance in the getter pump section.

[0050] Fig. 5 is a cross-sectional view showing an example of a getter pump section in a turbo molecular pump according to embodiment 1. In embodiment 1, for example as shown in Fig. 5, the getter pump section is disposed in a ring-shaped fixed vane spacer 125b in the stator section. Specifically, an annular groove 301 is formed along the circumferential direction on the inner peripheral surface of the fixed vane spacer 125b, and a gas adsorbing body 401 is disposed in the groove 301.

[0051] In the first embodiment, the gas adsorbing material 401 may be in the form of pellets or powder, and is a gas adsorbing material for a non-evaporative getter pump (NEG pump). The gas adsorbing material 401 is made of an existing metal for NEG pumps, such as titanium, zirconium, vanadium, iron, or an alloy of a plurality of metals among them. In order to prevent the gas adsorbing material 401 from falling off into the hollow portion of the fixed wing spacer 125b, for example, the gas adsorbing material 401 is fixed to the groove 301, or a mesh member is provided at the opening of the groove 301.

[0052] As described above, the stator section includes multiple stages of fixed vanes 123 (first stage fixed vane 123a, second stage fixed vane 123b, third stage fixed vane 123c, ...) and multiple stages of fixed vane spacers 125 (125a, 125b, 125c, ...) that position the multiple stages of fixed vanes 123, and in the first embodiment, the getter pump section is disposed on at least one stage of fixed vane among the multiple stages of fixed vanes 123, or at least one stage of fixed vane spacer among the multiple stages of fixed vane spacers 125. Note that the getter pump section shown in FIG. 5 is disposed on one stage of fixed vane spacer 125b, but multiple getter pump sections may be disposed on each of the multiple stages of fixed vane spacers.

[0053] In the first embodiment, the getter pump section is disposed on the exhaust port side 133 from the first stage rotor 102a (the rotor closest to the intake port 101) of the multiple stages of rotors 102. In this embodiment, the getter pump section is disposed on the first stage fixed blade spacer 125b, for example, as shown in FIG.

[0054] Furthermore, in the first embodiment, the heater section 402 is disposed in the fixed wing spacer 125b. Specifically, for example, as shown in Fig. 5, an annular groove 302 is formed in the outer peripheral surface of the fixed wing spacer 125b in correspondence with the groove 301, and a resistance heating element serving as the heater section 402 is wound around the wall surface of the groove 302 along the axial direction.

[0055] Furthermore, in the first embodiment, a temperature sensor 403 for controlling the temperature of gas adsorbing material 401 is disposed on fixed wing spacer 125b adjacent to heater section 402. An output signal from temperature sensor 403 is output to control device 200, which controls the current flowing to heater section 402 based on the output signal from temperature sensor 403, thereby controlling the temperature of gas adsorbing material 401 during activation and / or regeneration.

[0056] Regarding temperature control of the gas adsorbing material 401 during activation and / or regeneration, the temperature sensor 403 may not be provided, and the control device 200 may monitor the conduction current of the heater section 402 and perform constant resistance control based on the conduction current to control the temperature of the gas adsorbing material 401.

[0057] Furthermore, in the first embodiment, a thermal resistance increasing means may be provided that increases the thermal resistance between a first member (i.e., fixed wing spacer 125b) on which the getter pump section is arranged and a second member (i.e., fixed wing 123b) adjacent to the first member, compared to when the two are in surface contact. For example, the thermal resistance increasing means is a heat insulating member sandwiched between the opposing surfaces of the first member and the second member, or a ring-shaped ridge formed on at least one of the opposing surfaces of the first member and the second member, or a plurality of ridges arranged on a circumference.

[0058] The casing also includes an external connection part that electrically connects the heater part 402 to an external circuit (not shown, such as a drive circuit for the heater part 402 controlled by the control device 200). For example, as shown in Fig. 5, the external connection part includes a hole 303 formed in the casing (outer cylinder 127), and a feed-through connector 404 and an O-ring 405 that seal the outer peripheral opening of the hole 303. The feed-through connector 404 has at least two terminals 404a.

[0059] Next, the operation of the turbo molecular pump 100 according to the first embodiment will be described.

[0060] (a) Operation of the pump

[0061] When the turbo molecular pump 100 is in operation, the motor 121 operates and the rotor part rotates under the control of the control device 200. As a result, gas flowing in through the intake port 101 is transported along the gas flow path between the rotor part and the stator part, and is discharged from the exhaust port 133 to an external pipe. In the getter pump part, gas molecules are adsorbed onto the surface of the gas adsorption body 401. At this time, the control device 200 does not operate the heater part 402.

[0062] In the turbo molecular pump section of the turbo molecular pump 100 (i.e., the pump section consisting of the rotor section and stator section described above), the pumping speed gradually decreases when the gas pressure falls below the high vacuum range, but in the getter pump section of the turbo molecular pump 100 (i.e., the gas adsorption body 401 described above), the pumping speed is approximately constant regardless of the gas pressure, making it possible to pump down to gas pressures below the high vacuum range.

[0063] In particular, in the case of light molecules such as hydrogen molecules, the pumping speed of the turbo molecular pump section is slow, but such molecules can be sufficiently pumped (adsorbed) by the getter pump section, so that such gas molecules remaining only in the turbo molecular pump section are also pumped by the getter pump section, and the influence on processes in the chamber upstream of the turbo molecular pump 100 can be suppressed.

[0064] (b) Actions taken upon activation or regeneration

[0065] During activation or regeneration, the control device 200 controls the temperature as described above, while controlling a drive circuit (not shown), and conducts current to the heater section 402 to raise the temperature of the gas adsorbing object 401 to a predetermined temperature, and maintains the temperature of the gas adsorbing object 401 at the predetermined temperature for a predetermined time, thereby activating or regenerating the gas adsorbing object 401. For example, during activation, the temperature of the gas adsorbing object 401 is raised to about 400 degrees Celsius, and during regeneration, the temperature of the gas adsorbing object 401 is raised to about 200 degrees Celsius. At that time, the control device 200 operates the motor 121 to rotate the rotor section. This makes it easier for the gas released from the gas adsorbing object 401 during activation and regeneration to be discharged along the gas flow path. In addition, since the gas adsorbing object 401 is disposed closer to the exhaust port 133 (downstream) than the rotor 123a, the gas released from the gas adsorbing object 401 is less likely to flow back during activation and regeneration.

[0066] As described above, according to the first embodiment, the turbomolecular pump 100 is provided with a getter pump section in the stator section or casing of the turbomolecular pump 100, and is also provided with a heater section 402 that performs at least one of activation and regeneration of the gas adsorbing material 401 in the getter pump section.

[0067] As a result, the gas is adsorbed by the gas adsorbing body 401 on the inner wall portion of the ring-shaped or cylindrical member facing the gas flow path, and the length of the intake port 101 in the axial direction does not need to be increased due to the gas adsorbing body 401. Also, since the getter pump section and the heater section are arranged in a specific member (the fixed blade spacer 125b in the first embodiment), a getter pump function can be easily added to an existing turbomolecular pump by replacing one member with the relevant member. Also, since there is almost no change in the size of the components of the existing turbomolecular pump, adding the getter pump function is less affected by the constraints on the installation space of the turbomolecular pump.

[0068] Embodiment 2

[0069] FIG. 6 is a cross-sectional view showing an example of a getter pump section in a turbo molecular pump 100 according to the second embodiment. In the second embodiment, as shown in FIG. 6, for example, a getter pump section (gas adsorption body 601) and a heater section 602 are arranged on the intake port 101 side of the first stage fixed vane 123a in the axial direction. Specifically, an annular groove 501 is formed along the circumferential direction on the inner peripheral surface of the front stage fixed vane spacer 125a, and a gas adsorption body 601 similar to the gas adsorption body 401 is arranged in the groove 501. Also, a heater section 602 similar to the heater section 402 is arranged in the fixed vane spacer 125a. Specifically, as shown in FIG. 6, for example, an annular groove 502 is formed on the outer peripheral surface of the fixed vane spacer 125a in correspondence with the groove 501, and a resistance heating element as the heater section 602 is wound around the wall surface of the groove 502 along the axial direction. Also, a temperature sensor 603 similar to the temperature sensor 403 is arranged in the groove 502.

[0070] Furthermore, the casing includes an external connection part that electrically connects the heater part 602 to an external circuit (not shown, such as a drive circuit for the heater part 602 controlled by the control device 200) For example, as shown in Fig. 6, the external connection part includes a hole 503, a feed-through connector 604, and an O-ring 605 similar to the above-mentioned hole 303, feed-through connector 404, and O-ring 405.

[0071] Other configurations and operations of the turbo molecular pump 100 according to the second embodiment are similar to those of the first embodiment, so the description thereof will be omitted.

[0072] Embodiment 3

[0073] FIG. 7 is a cross-sectional view showing an example of a getter pump section in a turbo molecular pump according to the third embodiment. In the third embodiment, as shown in FIG. 7, for example, a getter pump section (gas adsorption body 801) and a heater section 802 are arranged in the above-mentioned casing (specifically, the outer cylinder 127). Specifically, an annular groove 701 is formed along the circumferential direction on the inner peripheral surface of the outer cylinder 127 facing the gas flow path, and a gas adsorption body 801 similar to the gas adsorption bodies 401 and 601 is arranged in the groove 701. In addition, a heater section 802 similar to the heater sections 402 and 602 is arranged in the outer cylinder 127. Specifically, as shown in FIG. 8, for example, an annular groove 702 is formed in the outer peripheral surface of the outer cylinder 127 corresponding to the groove 701, and a resistance heating element as the heater section 802 is wound on the wall surface along the axial direction of the groove 702. In addition, a temperature sensor 803 similar to the temperature sensors 403 and 603 is arranged in the groove 702.

[0074] Other configurations and operations of the turbo molecular pump 100 according to the third embodiment are similar to those of the first or second embodiment, so that the description thereof will be omitted.

[0075] It should be noted that various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. In other words, such changes and modifications are intended to be included within the scope of the claims.

[0076] For example, in the above embodiments 1, 2 and 3, the heater section 402, 602, 802 is arranged in a component in which the getter pump section (gas adsorption body 401, 601, 801) is arranged, but the heater section 402, 602, 802 may be arranged in a component other than the component in which the getter pump section is arranged (a component adjacent to the component in which the getter pump section is arranged).

[0077] In the above-mentioned first, second and third embodiments, the heater section 402, 602, 802 may also function as a baking heater for discharging gas remaining inside the pump during the initial exhaust. This eliminates the need to separately install a baking heater, thereby reducing costs.

[0078] Furthermore, in the above-mentioned embodiments 1, 2 and 3, the fixed wing spacer 125 of each stage may be composed of one member, or may be composed of multiple (e.g., two) members divided in the circumferential direction and connected together.

[0079] Furthermore, in the above-mentioned first, second and third embodiments, the getter pump section (gas adsorbing body 401, 601, 801) is disposed at a position where the temperature does not rise to the required temperature for regeneration due to heat generated during pump operation.

[0080] Furthermore, in the above first, second and third embodiments, a plurality of recesses may be provided in place of the grooves 301, 501 and 701, and the gas adsorbing bodies 401, 601 and 801 may be similarly arranged in the plurality of recesses.

[0081] Furthermore, in the first and second embodiments, in the outer cylinder 127, instead of the holes 303 and 503, holes for other purposes (for example, various ports such as a vent valve) may be used.

[0082] Each of the above embodiments may be combined with other embodiments as necessary.

[0083] In the above first, second and third embodiments, the getter pump section may be an evaporation type getter pump. [Industrial Applicability]

[0084] The present invention is applicable to, for example, turbomolecular pumps. [Explanation of symbols]

[0085] 100 Turbomolecular Pump 101 Air intake (part of an example of a casing) 102 Rotor (part of an example of a rotor section) 103 Rotating body (part of an example of a rotor part) 123 Fixed blade (part of an example of a stator section) 125 Fixed blade spacer (part of an example of a stator section) 127 External cylinder (part of an example of a casing) 303,503 holes (examples of external connections) 401, 601, 801 Gas adsorbent (example of getter pump section) 402,602,802 Heater section 403,603,803 Temperature Sensors 404,604 Feed-through connectors (some examples of external connections) 405,605 O-rings (examples of external connections)

Claims

1. In a turbomolecular pump having a rotor portion and a stator portion in a casing, a getter pump section disposed in the stator section; a heater section for at least one of activating and regenerating the gas adsorbing substance in the getter pump section; a temperature sensor for controlling the temperature of the gas adsorbing body; a control device; the control device controls the temperature of the gas adsorbing body based on an output signal from the temperature sensor; the stator portion includes a plurality of stages of fixed blades and a plurality of stages of fixed blade spacers that position the plurality of stages of fixed blades, the temperature sensor is disposed in the stator portion; A turbomolecular pump characterized by:

2. The getter pump section is disposed in at least one fixed wing of the multiple stages of fixed wing, or at least one fixed wing spacer of the multiple stages of fixed wing spacers; 2. The turbomolecular pump according to claim 1,

3. 3. The turbomolecular pump according to claim 2, wherein the heater portion is disposed on the fixed vane spacer.

4. A turbomolecular pump having a rotor portion and a stator portion within a casing, a getter pump section disposed in the stator section or the casing; a heater section for at least one of activating and regenerating the gas adsorbing substance in the getter pump section; a control device; the control device specifies a conduction current of the heater unit and performs constant resistance control based on the conduction current to control the temperature of the gas adsorbing body; A turbomolecular pump characterized by:

5. A turbomolecular pump having a rotor portion and a stator portion within a casing, a getter pump section disposed in the stator section or the casing; a heater section for at least one of activating and regenerating the gas adsorbing substance in the getter pump section; a thermal resistance increasing means for increasing a thermal resistance between a first member in which the getter pump portion is arranged and a second member adjacent to the first member, compared to a case in which the first member and the second member are in surface contact with each other; A turbomolecular pump comprising:

6. The rotor portion includes a plurality of rotor blades. the getter pump section is disposed closer to the exhaust port than a first stage rotor blade of the plurality of stages of rotor blades; 2. The turbomolecular pump according to claim 1,

7. The casing includes an external connection portion that electrically connects the heater portion to an external circuit; 2. The turbomolecular pump according to claim 1,

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