Vacuum pump and cleaning system for a vacuum pump

Abstract

Provided is a vacuum pump capable of decomposing and particleizing byproducts by means of radicals and effectively discharging them to the outside. The vacuum pump is provided with an outer cylinder (127) having a suction port (101) and a discharge port (133), a rotor shaft (113) rotatably supported inside the outer cylinder (127), and a rotating body (103) having a plurality of rotating blades (102) fixed to the rotor shaft (113) and capable of rotating together with the rotor shaft (113). The vacuum pump is provided with at least one radical supply port (201a) capable of supplying a plurality of types of radicals into the outer cylinder (127) and a radical supply mechanism (201) that supplies radicals to the radical supply port (201a).

Description

Technical Field

[0001] This invention relates to vacuum pumps and vacuum pump cleaning systems, and particularly to vacuum pumps and vacuum pump cleaning systems capable of removing deposits or similar materials formed by solidification of gas inside the vacuum pump. Background Technology

[0002] In recent years, in the process of forming semiconductor devices from wafers that serve as substrates, a method has been adopted to manufacture semiconductor devices by processing the wafers in a processing chamber of a semiconductor manufacturing apparatus that is maintained at a high vacuum. In the semiconductor manufacturing apparatus that processes the wafers in a vacuum chamber, a vacuum pump equipped with a turbomolecular pump section and a grooved pump section is used in order to achieve and maintain a high vacuum level (for example, see Patent Document 1).

[0003] The turbomolecular pump section has thin, rotatable metal blades and fixed blades inside the housing. Furthermore, by rotating the blades at a high speed, for example, several hundred m / s, the process gas used in the processing that enters from the intake side is compressed inside the pump and discharged from the exhaust side.

[0004] However, during the compression process, as the molecules of the process gas drawn in from the vacuum pump's intake port move towards the exhaust port as the rotating blades move within the pump, the process gas solidifies. These solidified byproducts adhere and accumulate on the fixed blades, the inner surface of the outer cylinder, and other surfaces. These byproducts obstruct the path of gas molecules towards the exhaust port. Consequently, problems arise such as decreased exhaust capacity of the vacuum pump, abnormal processing pressure, and interruptions in the handling of these byproducts, leading to decreased production efficiency.

[0005] In addition, there is a problem of process gas particles rebounding from the vacuum pump side flowing back into the processing chamber (cavity) of the semiconductor manufacturing device, causing wafer contamination.

[0006] As a countermeasure, a vacuum pump with a free radical supply device installed at the suction port of the vacuum pump has been proposed. The free radical supply device generates free radicals to peel off and decompose deposits attached to and accumulated on the fixed blades, the inner surface of the outer cylinder, etc. (for example, see Patent Document 2).

[0007] The technology known in Patent Document 2 provides a free radical supply section near the intake port of a vacuum pump, and supplies free radicals by ejecting them from the nozzle of the free radical supply section toward the inner center.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-82120

[0011] Patent Document 2: Japanese Patent Application Publication No. 2008-248825. Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] The invention described in Patent Document 2 employs the following structure: near the intake port on the side adjacent to the chamber of a semiconductor manufacturing apparatus, and at the uppermost position of the rotating blade and the fixed blade, free radicals from the free radical supply unit are ejected from the nozzle toward the inner center. Furthermore, the free radicals supplied from the free radical supply unit flow together with the process gas inside the outer cylinder toward the exhaust port, decomposing and particleizing deposits adhering to the fixed blade, the inner surface of the outer cylinder, etc., and are discharged from the exhaust port along with the process gas.

[0014] In this configuration, where free radicals are supplied from the suction port on the side adjacent to the chamber and from the uppermost position of the rotating and fixed blades, there is a problem that if byproducts at the suction port, which is the inlet side of the vacuum pump, react with the free radicals and become atomized, they flow back into the chamber and become a major cause of wafer defects.

[0015] Furthermore, free radicals, being unstable substances that impart significant energy to the feed gas and forcibly break molecular bonds, recombine and lose their activity within a relatively short time. Therefore, even when supplied from the vacuum pump's intake port, free radicals lose their activity due to collisions with each other, stator blades, and the casing, recombineing before reaching the vicinity of the vacuum pump's exhaust port. Consequently, there is a problem where free radicals are not distributed throughout the vacuum pump's interior, hindering effective cleaning.

[0016] Furthermore, if the supply of free radicals for cleaning becomes excessive, in addition to the decomposition of byproducts, there is also the problem of deterioration of the process chamber and the components that make up the vacuum pump.

[0017] In addition, byproducts such as TiN (tin) that cannot be particle-generated by single radical reactions have recently been observed.

[0018] In view of this, in order to provide a vacuum pump that can decompose and granulate byproducts with the aid of free radicals and effectively discharge them to the outside, a technical problem has arisen that needs to be solved, and the present invention aims to solve this problem.

[0019] Methods used to solve problems

[0020] The present invention is proposed to achieve the above-mentioned objective. The invention described in technical solution 1 provides a vacuum pump comprising: a housing having an intake port and an exhaust port; a rotor shaft rotatably supported inside the aforementioned housing; and a rotating body having rotating blades fixed to the aforementioned rotor shaft and capable of rotating together with the aforementioned rotor shaft; the aforementioned vacuum pump includes at least one free radical supply port capable of supplying multiple types of free radicals into the aforementioned housing and a free radical supply mechanism for supplying the aforementioned free radicals to the aforementioned free radical supply port.

[0021] According to this structure, when particleization cannot be achieved through the reaction of a single free radical, multiple types of free radicals can be supplied from the free radical supply port of the free radical supply mechanism, and the accumulation of byproducts that can be particleized through stages using multiple types of free radicals can be effectively particleized and discharged.

[0022] The invention described in technical solution 2, in the structure described in technical solution 1, provides a vacuum pump, wherein the aforementioned free radical supply mechanism has a free radical generation source that matches the generation of the aforementioned multiple types of free radicals and a power source that drives the aforementioned free radical generation source.

[0023] According to this structure, since the free radical supply mechanism has a free radical generation source that matches the generation of different types of free radicals and a power source that drives the free radical generation source, it is possible to generate different types of free radicals through the free radical generation source that matches the generation of different types of free radicals and the power source that drives the free radical generation source, and to effectively granulate and discharge the accumulation of byproducts that can be granulated by using multiple types of free radicals through stages.

[0024] The invention described in technical solution 3, in the structure described in technical solution 2, provides a vacuum pump in which at least a portion of the power supply driven by the aforementioned multiple types of free radical generation sources is shared with the power supply for pump control.

[0025] Each type of free radical generator requires a separate power source to drive it. However, if there are multiple power sources, there will be problems such as increased cost and insufficient space. But in this structure, by sharing at least a portion of the power source with the power source for pump control, it is possible to expect the effects of reduced cost and space.

[0026] The invention described in technical solution 4, in the structure described in technical solution 2, provides a vacuum pump that shares at least a portion of the power source driven by the aforementioned multiple types of free radical generation sources with the power source for plasma generation in the chamber.

[0027] Each type of free radical generator requires a separate power source to drive it. However, if there are multiple power sources, there will be problems such as increased cost and insufficient space. But in this structure, by sharing at least a portion of the power source with the plasma generation power source of the chamber, it is expected that the cost and space will be reduced.

[0028] The invention described in technical solution 5, in the structure described in any one of technical solutions 2 to 4, provides a vacuum pump, wherein the aforementioned free radical generation source has replaceable electrodes, the power supply of the aforementioned free radical generation source has a variable voltage output function, and the generation of various free radicals can be achieved by replacing the aforementioned electrodes and adjusting the voltage output of the aforementioned power supply.

[0029] According to this structure, since the free radical generation source can replace the electrodes, and the power supply has a variable voltage output function, the generation of various free radicals can be achieved by replacing the electrodes and adjusting the voltage output of the power supply.

[0030] The invention described in technical solution 6, in the structure described in any one of technical solutions 1 to 5, provides a vacuum pump, wherein the aforementioned free radical supply mechanism has a valve, the valve being respectively provided corresponding to the aforementioned free radical supply port, and is capable of controlling the supply of the aforementioned free radicals supplied from the aforementioned free radical supply ports.

[0031] According to this structure, the supply amount of free radicals supplied from each free radical supply port can be controlled by valves provided corresponding to each free radical supply port, so that the required amount of free radicals can be supplied from each free radical supply port.

[0032] The invention described in technical solution 7, in the structure described in any one of technical solutions 1 to 6, provides a vacuum pump in which the aforementioned free radical supply ports are respectively arranged in the axial direction of the aforementioned rotor shaft at a position approximately equal to the aforementioned suction port.

[0033] According to this structure, since each free radical supply port is arranged axially at a position approximately equal to the intake port, it is easy to adjust the amount and timing of free radicals supplied from each free radical supply port.

[0034] The invention described in technical solution 8, in the structure described in any one of technical solutions 1 to 6, provides a vacuum pump, wherein the vacuum pump further comprises a controller for controlling the opening and closing of the aforementioned valve.

[0035] According to this structure, the amount and timing of free radicals supplied from each free radical supply port can be easily adjusted via a controller. Furthermore, the controller can receive signals from external devices (such as semiconductor manufacturing equipment) and arbitrarily supply free radicals into the vacuum pump.

[0036] The invention described in technical solution 9, in the structure described in technical solution 8, provides a vacuum pump, wherein the aforementioned controller controls the opening and closing of the aforementioned valve based on operating data representing the operating status of the aforementioned vacuum pump.

[0037] Based on this structure, the controller itself can determine the state of the vacuum pump based on the operating data of the vacuum pump and automatically supply free radicals into the vacuum pump.

[0038] The invention described in technical solution 10, in the structure described in technical solution 9, provides a vacuum pump in which the controller determines that byproduct accumulation is progressing and that the supply of free radicals is required for cleaning the byproducts when the current value of the motor that drives the rotor shaft to rotate, which is the aforementioned operating data, exceeds a predetermined threshold.

[0039] According to this structure, when the current value of the motor that drives the rotor shaft to rotate, which is used as operating data, exceeds a specified threshold, the controller determines that the byproducts are accumulating and that a supply of free radicals is needed to clean the byproducts, and can automatically supply free radicals to the vacuum pump.

[0040] The invention described in technical solution 11, in the structure described in technical solution 9, provides a vacuum pump in which the aforementioned controller controls the opening and closing of the aforementioned valve when the current value of the motor that drives the aforementioned rotor shaft to rotate, which is the aforementioned operating data, is approximately equal to the current value of the aforementioned motor when operating without load, which is stored in advance.

[0041] According to this structure, the controller compares the current value of the motor when it is running without load with the current value of the vacuum pump. When the current value is approximately equal to the current value of the motor when it is running without load, it is determined that there is no inflow of process gas and free radicals can be automatically supplied to the vacuum pump.

[0042] The invention described in technical solution 12, in the structure described in technical solution 9, provides a vacuum pump, wherein when the pressure value of the vacuum pump, which is the aforementioned operating data, exceeds a predetermined threshold, the aforementioned controller determines that the accumulation of byproducts is progressing and that the supply of the aforementioned free radicals is required for the cleaning of the byproducts.

[0043] According to this structure, the controller itself judges the accumulation state of byproducts in the vacuum pump based on the pressure value of the vacuum pump, and decides whether it is necessary to supply free radicals to the vacuum pump in order to clean the byproducts. When needed, it can automatically supply free radicals to the vacuum pump.

[0044] The invention described in technical solution 13, in the structure described in technical solution 9, provides a vacuum pump in which the aforementioned controller controls the opening and closing of the aforementioned valve when the pressure value of the aforementioned vacuum pump, which is the aforementioned operating data, is approximately equal to the pressure value of the aforementioned vacuum pump during pre-stored no-load operation.

[0045] According to this structure, the controller compares the pressure value of the vacuum pump under no-load operation with the current pressure value of the vacuum pump. When the pressure value is approximately equal to that under no-load operation, it is determined that there is no inflow of process gas and free radicals can be automatically supplied into the vacuum pump.

[0046] The invention described in technical solution 14 provides a cleaning system for a vacuum pump, the vacuum pump comprising: a housing having an intake port and an exhaust port; a rotor shaft rotatably supported inside the housing; and a rotating body having rotating blades fixed to the rotor shaft and capable of rotating together with the rotor shaft; the cleaning system for the vacuum pump comprises at least one free radical supply mechanism capable of supplying multiple types of free radicals into the housing.

[0047] According to the system structure, when the reaction of a single free radical cannot be granulated, multiple types of free radicals can be supplied from the free radical supply port of the free radical supply mechanism, and the accumulation of by-products that can be granulated by using multiple types of free radicals through stages can be effectively granulated and discharged.

[0048] Invention Effects

[0049] According to the invention, since it has a free radical supply port capable of supplying multiple types of free radicals into the shell and a free radical supply mechanism for supplying free radicals to the free radical supply port, in cases where particle formation cannot be achieved by a single free radical reaction, multiple types of free radicals can be supplied from the free radical supply port of the free radical supply mechanism, effectively particle-forming and discharging the accumulation of byproducts that can be particle-formed through a process using multiple types of free radicals, thus performing a cleaning process.

[0050] Furthermore, by supplying free radicals into the vacuum pump, a sufficient amount of free radicals can be supplied to the vacuum pump to enable the byproducts to react, thus minimizing the degradation of the vacuum pump material itself and minimizing the supply of the gas required for free radical generation.

[0051] Furthermore, when each free radical supply port is positioned on the axial direction of the rotor shaft, closer to the exhaust port than the fixed blade closest to the intake port, when a portion of the particles that have reacted with the free radicals and become atomized are about to return to the intake port (chamber side), the portion of the particles heading towards the intake port collides with the fixed blade positioned on the intake port side, preventing them from heading towards the intake port side. This also suppresses the return of a portion of the particles to the intake port side, thus reducing the defect rate in semiconductor manufacturing equipment and the like.

[0052] Furthermore, since byproducts can be particle-ized and expelled from the vacuum pump using free radicals, it is no longer necessary to stop semiconductor manufacturing equipment and other equipment to clean, repair, or replace the vacuum pump. This not only improves semiconductor production efficiency but also reduces cleaning, repair, and replacement costs. Attached Figure Description

[0053] Figure 1 This is a longitudinal sectional view of a turbomolecular pump, representing an embodiment of a vacuum pump according to an embodiment of the present invention.

[0054] Figure 2 This is a diagram illustrating an example of the amplifier circuit in the same turbomolecular pump.

[0055] Figure 3 This is a time graph representing a control example where the current command value detected by the amplifier circuit in the same turbomolecular pump is greater than the detected value.

[0056] Figure 4 This is a time graph representing a control example where the current command value detected by the amplifier circuit in the same turbomolecular pump is smaller than the detected value.

[0057] Figure 5 This is a time diagram illustrating a control example performed by the controller in the same turbomolecular pump.

[0058] Figure 6 This is a schematic diagram used to illustrate the effect of the placement of the free radical supply port in the turbomolecular pump as described above.

[0059] Figure 7 This is a longitudinal sectional view of a turbomolecular pump, representing another embodiment of a vacuum pump according to an embodiment of the present invention. Detailed Implementation

[0060] In order to achieve the objective of providing a vacuum pump capable of effectively discharging byproducts by means of free radical decomposition into particles, the present invention achieves this by constructing a vacuum pump comprising: a housing having an intake port and an exhaust port; a rotor shaft rotatably supported inside the housing; and a rotating body having a plurality of rotating blades fixed to the rotor shaft and capable of rotating together with the rotor shaft; and at least one free radical supply port capable of supplying a plurality of types of free radicals into the housing and a free radical supply mechanism for supplying the free radicals to the free radical supply port. Example

[0061] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in the following embodiments, when referring to the quantity, value, amount, range, etc., of the constituent elements, they are not limited to that specific number, except where specifically stated or clearly limited in principle to a particular number; they can be either more than or less than that specific number.

[0062] Furthermore, when referring to the shape and positional relationship of constituent elements, etc., it substantially includes those that are similar or analogous to their shape, except in cases that are specifically stated or are obviously not so in principle.

[0063] Furthermore, in order to facilitate understanding of the features, the accompanying drawings may exaggerate characteristic parts by enlarging them, and the size ratios of the constituent elements are not limited to being the same as the actual dimensions. Additionally, in sectional views, to facilitate understanding of the cross-sectional structure of the constituent elements, some section lines of the constituent elements may be omitted.

[0064] Furthermore, in the following description, expressions of direction such as up and down, left and right are not absolute. They are suitable when the various parts of the turbomolecular pump of the present invention are depicted in the given posture, but should be interpreted differently depending on the posture. Moreover, throughout the description of the embodiments, the same reference numerals are given to the same elements.

[0065] Figure 1 This is a diagram illustrating one embodiment of a turbomolecular pump 100, which is a vacuum pump according to the present invention. Figure 1 This is its longitudinal sectional view. In the following description, it will be... Figure 1 The left side is defined as the front of the device, the right side as the rear, the up and down direction as up and down, and the direction perpendicular to the paper as left and right.

[0066] exist Figure 1In this turbomolecular pump 100, an intake port 101 is formed at the upper end of an outer cylinder 127, which is cylindrical and serves as the housing. Furthermore, inside the outer cylinder 127, there is a rotating body 103 with multiple rotating blades 102 (102a, 102b, 102c...) formed radially and in multiple layers around its periphery. These rotating blades 102 (102a, 102b, 102c...) are turbine blades used to draw in and expel gas. A rotor shaft 113 is mounted at the center of this rotating body 103. This rotor shaft 113 is suspended in the air by, for example, a 5-axis controlled magnetic bearing and its position is controlled.

[0067] Four upper radial electromagnets 104 are arranged in pairs along the X and Y axes. Near each upper radial electromagnet 104, and corresponding to each of them, four upper radial sensors 107 are provided. These upper radial sensors 107, for example, use inductive sensors with conductive windings or eddy current sensors, and detect the position of the rotor shaft 113 based on changes in the inductance of the conductive windings that correspond 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 this information to the controller 200.

[0068] In this controller 200, for example, a compensation circuit with PID control function generates an excitation control command signal for the upper radial electromagnet 104 based on the position signal detected by the upper radial sensor 107. Figure 2 The amplifier circuit 150 shown (described later) excites the upper radial electromagnet 104 based on the excitation control command signal, thereby adjusting the upper radial position of the rotor shaft 113.

[0069] Furthermore, the rotor shaft 113 is formed of a material with high magnetic permeability (iron, stainless steel, etc.) 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 respectively. In addition, the lower radial electromagnet 105 and the lower radial sensor 108 are configured in the same way as the upper radial electromagnet 104 and the upper radial sensor 107, and the lower radial position of the rotor shaft 113 is adjusted in the same way as the upper radial position.

[0070] Furthermore, axial electromagnets 106A and 106B are configured to sandwich a circular metal disc 111 mounted on the lower part of the rotor shaft 113. The metal disc 111 is made of a material with high magnetic permeability, such as iron. An axial sensor 109 is provided to detect axial displacement of the rotor shaft 113, and its axial position signal is sent to the controller 200.

[0071] Furthermore, in the controller 200, for example, a compensation circuit with PID regulation function generates excitation control command signals for axial electromagnets 106A and 106B based on the axial position signal detected by the axial sensor 109. The amplifier circuit 150 performs excitation control on axial electromagnets 106A and 106B based on these excitation control command signals. As a result, axial electromagnet 106A attracts metal disk 111 upward by magnetic force, and axial electromagnet 106B attracts metal disk 111 downward, thereby adjusting the axial position of rotor shaft 113.

[0072] In this way, the controller 200 appropriately adjusts the magnetic force exerted on the metal disk 111 by the axial electromagnets 106A and 106B, so that the rotor shaft 113 is magnetically levitated in the axial direction and held in space without contact. Furthermore, the amplifier circuit 150 that controls the excitation of these upper radial electromagnets 104, lower radial electromagnets 105, and axial electromagnets 106A and 106B will be described later.

[0073] On the other hand, the motor 121 has a plurality of magnetic poles arranged circumferentially around the rotor shaft 113. Each magnetic pole is controlled by the controller 200 to drive the rotor shaft 113 to rotate via an electromagnetic force acting between the rotor shaft 113 and the controller 200. Furthermore, a rotational speed sensor (not shown), such as a Hall element, a resolver, or an encoder, is installed in the motor 121 to detect the rotational speed of the rotor shaft 113 based on the detection signal from the rotational speed sensor.

[0074] Furthermore, for example, a phase sensor (not shown) is mounted near the lower radial sensor 108 to detect the phase of rotation of the rotor shaft 113. In the controller 200, the detection signals from this phase sensor and the rotational speed sensor are used together to detect the position of the magnetic poles.

[0075] Multiple fixed blades 123a, 123b, 123c, 123d... are provided with a slight gap between them and the rotating blades 102 (102a, 102b, 102c, 102d...). The rotating blades 102 (102a, 102b, 102c, 102d...) are formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to move the molecules of the exhaust gas downward by collision.

[0076] Furthermore, the fixed blade 123 is also formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and is disposed offset from the layers of the rotating blade 102 towards the inside of the outer cylinder 127. Moreover, the outer peripheral end of the fixed blade 123 is supported in a state of being inserted between multiple stacked fixed blade spacers 125 (125a, 125b, 125c, 125d...).

[0077] The fixed blade spacer 125 is an annular component, made of metals such as aluminum, iron, stainless steel, copper, or alloys containing these metals. A slightly spaced outer cylinder 127 is fixed to the outer periphery of the fixed blade spacer 125. A base portion 129 is provided at the bottom of the outer cylinder 127. An exhaust port 133 and a purge gas supply port 134 are formed in the base portion 129, communicating with the outside. Exhaust gas entering the intake port 101 from the chamber side and being transferred to the base portion 129, and free radicals transferred from the free radical supply port 201a (described later), are supplied to the exhaust port 133.

[0078] Furthermore, depending on the application of the turbomolecular pump 100, a threaded spacer 131 is provided between the lower part of the fixed blade spacer 125 and the base part 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 multiple helical threaded grooves 131a engraved on its inner circumferential surface. The direction of the helix of the threaded grooves 131a is the direction in which the molecules of the exhaust gas are moved toward the exhaust port 133 when they move in the rotation direction of the rotating body 103.

[0079] At the lowest part of the rotating body 103, following the rotating blades 102 (102a, 102b, 102c...), a cylindrical portion 103b is vertically provided. The outer circumferential surface of this cylindrical portion 103b is cylindrical and extends toward the inner circumferential surface of the threaded spacer 131, approaching the inner circumferential surface of the threaded spacer 131 with a predetermined gap. The exhaust gas, which is moved to the threaded groove 131a by the rotating blades 102 and the fixed blades 123, is guided by the threaded groove 131a and conveyed to the base portion 129.

[0080] The base portion 129 is a disc-shaped component that forms the base of the turbomolecular pump 100, and is generally made of metals such as iron, aluminum, or stainless steel. Since the base portion 129 physically holds the turbomolecular pump 100 and also functions as a heat conduction path, it is preferable to use a metal with rigidity and high thermal conductivity such as iron, aluminum, or copper.

[0081] Furthermore, depending on the application of the turbomolecular pump 100, a plurality of free radical supply mechanisms 201 are provided between the fixed blade spacer 125 and the rotating blade 102. Each free radical supply mechanism 201 has a free radical supply port 201a, a free radical supply valve 201b, and a free radical generation source 201c. In this embodiment, two free radical supply mechanisms 201, free radical supply mechanism 201A and free radical supply mechanism 201B, are provided, but any one or more free radical supply mechanisms 201 are acceptable.

[0082] Furthermore, the free radical supply port 201a of each free radical supply mechanism 201 (201A, 201B) is located in the axial direction of the rotating body 103 (in the direction of the free radical supply port 201a). Figure 1 In the vertical direction of the turbomolecular pump 100, at least one fixed blade 102a closest to the intake port 101 is positioned on the side near the exhaust port 133, i.e., in... Figure 1 In this embodiment, the free radical supply port 201a is positioned between the fixed blade 123c and the rotating blade 102d. Therefore, the free radical supply ports 201a of each free radical supply mechanism 201 are positioned at the same height from the intake port 101, that is, at approximately equal axial distances from the intake port 101. Furthermore, they are positioned approximately equally spaced apart in the rotational direction, with the free radical supply direction facing the axis of the rotating body 103 and arranged approximately parallel to the rotating blade 102 and the fixed blade 123. Thus, free radicals are blown out from each free radical supply port 201a towards the axis of the rotating body 103. Furthermore, multiple types of free radicals are prepared so that the free radicals blown out from each free radical supply port 201a can effectively atomize the deposits and discharge them together with the free radicals from the exhaust port 133. The deposits are composed of byproducts that can be atomized using multiple types of free radicals through a process. Therefore, in this embodiment, different types of free radicals can be supplied from each free radical supply port 201a. Furthermore, when a single free radical is sufficient, there are cases where the same type of free radical is supplied from each free radical supply port 201a. In addition, even when different types of free radicals need to be supplied, there are cases where the same free radical supply port 201a is used to supply different types of free radicals from the same free radical supply port 201a in order to reduce the number of free radical supply ports 201a.

[0083] Each free radical supply valve 201b of the free radical supply mechanism 201 is respectively disposed between the free radical supply port 201a and the free radical generation source 201c. Each free radical supply valve 201b can adjust the supply amount of free radicals from the corresponding free radical generation source 201c to the free radical supply port 201a. The opening and closing control of each free radical supply valve 201b is performed by the aforementioned controller 200. The controller 200 is mainly composed of a microcomputer. In addition to various control circuits, the controller 200 also contains and modularizes a program that can control the entire turbomolecular pump 100 in a predetermined sequence.

[0084] The system is configured such that each radical supply mechanism 201's radical generation source 201c can supply multiple types of radicals, each corresponding to a different type of intended byproduct, so that byproducts that can be particled using multiple types of radicals through a process as described above can be particled. However, even when particleization can be performed using a single radical, there are also cases where the same type of radical is supplied from all radical generation sources 201c.

[0085] Next, regarding the turbomolecular pump 100 configured in this way, an amplifier circuit 150 for excitation control of its upper radial electromagnet 104, lower radial electromagnet 105, and axial electromagnets 106A and 106B will be described. Figure 2 The diagram below shows the circuit diagram of amplifier circuit 150.

[0086] exist Figure 2 In this configuration, one end of the electromagnet winding 151, which forms the upper radial electromagnet 104, is connected to the positive terminal 171a of the power supply 171 via transistor 161, and the other end is connected to the negative terminal 171b of the power supply 171 via current detection circuit 181 and transistor 162. Furthermore, transistors 161 and 162 are so-called power MOSFETs, which have a structure in which a diode is connected between its source and drain.

[0087] At this time, the cathode terminal 161a of transistor 161 is connected to the positive terminal 171a, and the anode terminal 161b is connected to one end of the electromagnet winding 151. Furthermore, the cathode terminal 162a of transistor 162 is connected to the current detection circuit 181, and the anode terminal 162b is connected to the negative terminal 171b.

[0088] On the other hand, the cathode terminal 165a of the diode 165 used for current regeneration is connected to one end of the electromagnet winding 151, and its anode terminal 165b is connected to the negative terminal 171b. Similarly, the cathode terminal 166a of the diode 166 used for current regeneration is connected to the positive terminal 171a, and its anode terminal 166b is connected to the other end of the electromagnet winding 151 via the current detection circuit 181. Furthermore, the current detection circuit 181 is, for example, composed of a Hall effect current sensor and a resistive element.

[0089] The amplifier circuit 150 configured as described above corresponds to one electromagnet. Therefore, when the magnetic bearing is 5-axis controlled and there are a total of 10 electromagnets 104, 105, 106A, and 106B, each electromagnet is configured with the same amplifier circuit 150, and the power supply 171 connects 10 amplifier circuits 150 in parallel.

[0090] Furthermore, the amplification control circuit 191 is, for example, composed of a digital signal processor (DSP) section (not shown) of the controller, which switches the transistors 161 and 162 on / off.

[0091] The amplification control circuit 191 compares the current value detected by the current detection circuit 181 (the signal reflecting this current value is called the current detection signal 191c) with a predetermined current command value. Then, based on the comparison result, it determines the magnitude of the pulse width (pulse width times Tp1, Tp2) generated within one control cycle Ts, which is the PWM control cycle. As a result, the amplification control circuit 191 outputs gate drive signals 191a and 191b with the pulse width to the gate terminals of transistors 161 and 162.

[0092] Furthermore, when the rotating body 103 accelerates through a resonance point or experiences interference during constant-speed operation, position control of the rotating body 103 under high speed and strong force is required. Therefore, a high voltage of approximately 50V is used as the power supply 171 to enable a rapid increase (or decrease) in the current flowing in the electromagnet winding 151. In addition, a capacitor (not shown) is typically connected between the positive terminal 171a and the negative terminal 171b of the power supply 171 to stabilize the power supply 171.

[0093] In this structure, if both transistors 161 and 162 are turned on, the current flowing in the electromagnet winding 151 (hereinafter referred to as electromagnet current iL) increases; if both are turned off, the electromagnet current iL decreases.

[0094] Furthermore, by setting one of transistors 161 and 162 to conduct and the other to cut off, the so-called flywheel current is maintained. Moreover, by allowing the flywheel current to flow into the amplifier circuit 150 in this way, hysteresis losses in the amplifier circuit 150 can be reduced, thus suppressing the overall power consumption of the circuit to a lower level. Furthermore, by controlling transistors 161 and 162 in this way, high-frequency noise such as high-order harmonics generated in the turbomolecular pump 100 can be reduced. Furthermore, by measuring this flywheel current using the current detection circuit 181, the electromagnet current iL flowing in the electromagnet winding 151 can be detected.

[0095] That is, when the detected current value is smaller than the current command value, such as Figure 3As shown, transistors 161 and 162 are turned on only once during the control period Ts (e.g., 100 μs) for a duration equivalent to the pulse width time Tp1. Therefore, the electromagnet current iL during this period increases toward the current value iLmax (not shown) that can flow from the positive terminal 171a to the negative terminal 171b via transistors 161 and 162.

[0096] On the other hand, if the detected current value is larger than the current command value, such as Figure 4 As shown, transistors 161 and 162 are turned off only once during the control cycle Ts for a duration equivalent to the pulse width time Tp2. Therefore, the electromagnet current iL during this period decreases toward the current value iLmin (not shown) that can be regenerated from the negative terminal 171b to the positive terminal 171a via diodes 165 and 166.

[0097] Furthermore, in both cases, one of transistors 161 and 162 is turned on after the pulse width times Tp1 and Tp2 have elapsed. Therefore, the flywheel current is maintained in the amplifier circuit 150 during this period.

[0098] In this structure, if the rotating blade 102 is driven to rotate by the motor 121 together with the rotor shaft 113, exhaust gas is drawn into the chamber through the intake port 101 by means of the action of the rotating blade 102 and the fixed blade 123. The exhaust gas drawn in from the intake port 101 is transferred to the base portion 129 between the rotating blade 102 and the fixed blade 123. At this time, the temperature of the rotating blade 102 rises due to frictional heat generated when the exhaust gas contacts the rotating blade 102, heat conduction generated by the motor 121, etc., but this heat is transferred to the fixed blade 123 side by radiation or conduction by gas molecules of the exhaust gas.

[0099] The fixed blade spacers 125 are joined together on the outer periphery to transfer the heat received by the fixed blade 123 from the rotating blade 102, the frictional heat generated when the exhaust gas comes into contact with the fixed blade 123, and so on to the outside.

[0100] Furthermore, in the above description, it was assumed that the threaded spacer 131 was disposed corresponding to the outer periphery of the cylindrical portion 103b of the rotating body 103, and that a threaded groove 131a was engraved on the inner peripheral surface of the threaded spacer 131. However, there are also cases where, conversely, a threaded groove is engraved on the outer peripheral surface of the cylindrical portion 103b, and a spacer with a cylindrical inner peripheral surface is disposed around it.

[0101] Furthermore, according to the application of the turbomolecular pump 100, in order to prevent the gas drawn from the intake port 101 from intruding into the electrical assembly consisting 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, and the axial sensor 109, the electrical assembly is surrounded by a stator column 122, and the stator column 122 is maintained at a specified pressure by the purge gas supplied from the purge gas supply port 134.

[0102] The supplied purging 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 circumferential cylindrical portion of the rotating blade 102.

[0103] Here, the turbomolecular pump 100 requires the determination of its specific model and control based on individually adjusted inherent parameters (e.g., characteristics corresponding to the model). To store these control parameters, the turbomolecular pump 100 includes an electronic circuit section 141 within its main body. The electronic circuit section 141 comprises electronic components such as a semiconductor memory (e.g., EEPROM) and semiconductor elements for accessing it, as well as a mounting substrate 143. This electronic circuit section 141 is housed below, for example, a rotational speed sensor (not shown) near the center of the base section 129 constituting the lower part of the turbomolecular pump 100, and is sealed by an airtight bottom cover 145.

[0104] However, in semiconductor manufacturing processes, among the process gases introduced into the chamber, there are gases that become solid if their pressure becomes higher than a specified value or their temperature becomes lower than a specified value. Inside the turbomolecular pump 100, the pressure of the exhaust gas is lowest at the intake port 101 and highest at the exhaust port 133. During the process gas's movement from the intake port 101 to the exhaust port 133, if its pressure becomes higher than a specified value or its temperature becomes lower than a specified value, the process gas becomes solid and accumulates inside the turbomolecular pump 100 as a byproduct.

[0105] For example, when SiCl4 is used as a process gas in an Al etching apparatus, the vapor pressure profile shows that under low vacuum (760 [torr] ~ 10... －2At low temperatures (approximately 20 °C), solid products (e.g., AlCl3) precipitate and accumulate inside the turbomolecular pump 100. Consequently, if byproducts of the process gas accumulate inside the turbomolecular pump 100, these accumulations narrow the pump flow path, contributing to a decrease in the performance of the turbomolecular pump 100. Furthermore, these products are prone to solidification and adhesion in the high-pressure areas near the exhaust port and the threaded spacer 131.

[0106] Therefore, in order to solve this problem, 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, for example. The heating of the heater and the cooling of the water-cooling pipe 149 are controlled based on the signal of the temperature sensor (hereinafter referred to as TMS; TMS; Temperature Management System) so as to maintain the temperature of the base portion 129 at a certain high temperature (set temperature).

[0107] Furthermore, during the compression of the process gas within the turbomolecular pump 100, the gas also solidifies and accumulates inside the outer cylinder 127. Therefore, during process interruptions, the controller 200 drives the free radical supply mechanism 201 to supply free radicals from the free radical supply port 201a into the outer cylinder 127 while adjusting the opening and closing of the free radical supply valve 201b, directing them towards the exhaust port 133. The accumulated byproducts are then reacted and decomposed into particles by the free radicals, and discharged from the exhaust port 133 to the outside of the outer cylinder 127 along with the free radicals.

[0108] exist Figure 5 This represents an example of an action of controller 200. Figure 5 The numbers in the middle represent the opening and closing actions of chamber valves (not shown) located between the chamber and the turbomolecular pump 100. Figure 1 The diagram shows the opening and closing actions of the free radical supply valve 201b in the free radical supply mechanism 201A, and similarly, the opening and closing actions of the free radical supply valve 201b in the free radical supply mechanism 201B. Figure 5 In the diagram, the Y-axis represents the opening and closing motion amount, and the X-axis represents the processing time T. Next, using... Figure 5 The timing diagram illustrates the actions of controller 200.

[0109] When the controller 200 performs chemical reaction processing such as etching on the wafer in the chamber, it particles the byproducts accumulated in the turbomolecular pump 100 and discharges them.

[0110] In this discharge process, firstly, a chamber valve (not shown) is switched from open to closed to prevent process gas from flowing into the turbomolecular pump 100. Once the chamber valve is confirmed to be closed, operation a within the chamber begins. Next, once time t5 (0.3 minutes) has elapsed since the chamber valve was closed, the free radical supply valve 201b of the free radical supply mechanism 201A is switched from closed to open, and this open state is maintained, for example, for time t6 (1 minute). Then, during the period when the free radical supply valve 201b is open, free radicals of type A are supplied from the free radical generation source 201c, and free radicals of type A (e.g., O free radicals) are supplied into the outer cylinder 127 from the free radical supply port 201a of the free radical supply mechanism 201A. Furthermore, when supplying free radicals, since the controller 200 controls the drive of the motor 121, given sufficient time to change the motor rotation, the rotation of the motor 121 can be switched to a lower rotation than the rated rotation, causing the drive of the rotating body 103 to operate at a low speed. Then, while the rotating body 103 is rotating, free radicals of type A are supplied into the outer cylinder 127.

[0111] Free radicals of type A, supplied to the outer cylinder 127 from the free radical supply port 201a of the free radical supply mechanism 201A, flow through the gap between the rotating blade 102 and the fixed blade 123 towards the exhaust port 133 within the outer cylinder 127, and are discharged from the exhaust port 133 to the outside of the outer cylinder 127. Furthermore, when the free radicals of type A flow through the gap between the rotating blade 102 and the fixed blade 123, if the free radicals of type A come into contact with deposits accumulated within the outer cylinder 127, they impart significant energy to the deposits reacting with the free radicals of type A, forcibly breaking down the molecular chains on the surface of the deposits into low-molecular-weight, atomized gas. Then, the low-molecular-weight, atomized gas, decomposed by the free radicals of type A, is discharged to the outside along with the free radicals through the exhaust port 133.

[0112] Furthermore, once the supply of type A free radicals from the free radical supply port (A) 201a of the free radical supply mechanism 201A to the outer cylinder 127 for time t6 (1 minute) ends, the free radical supply valve 201b of the free radical supply mechanism 201A is switched from open to closed again, stopping the supply of type A free radicals from the free radical supply port 201a to the outer cylinder 127.

[0113] Once the free radical supply valve 201b of the free radical supply mechanism 201A is switched to closed, the free radical supply valve (B) 201b of the free radical supply mechanism 201B is switched from closed to open after time t7 (0.5 minutes), and the open state of the free radical supply valve 201b of the free radical supply mechanism 201B is maintained, for example, for time t8 (1 minute). Then, during the period when the free radical supply valve 201b in the free radical supply mechanism 201B is open, free radicals of type B (e.g., F free radicals) are supplied from the free radical generation source 201c in the free radical supply mechanism 201B to the outer cylinder 127 via the free radical supply port 201a. In addition, when supplying free radicals of type B, since the controller 200 controls the drive of the motor 121, if there is sufficient time to change the motor rotation, the rotation of the motor 121 can also be switched to a rotation lower than the rated rotation, so that the drive of the rotating body 103 operates at a low speed. Then, while the rotating body 103 is rotating, free radicals of type B are supplied into the outer cylinder 127.

[0114] Free radicals of type B, supplied to the outer cylinder 127 from the free radical supply port 201a of the free radical supply mechanism 201B, flow through the gap between the rotating blade 102 and the fixed blade 123 towards the exhaust port 133 within the outer cylinder 127, and are discharged from the exhaust port 133 to the outside of the outer cylinder 127. Furthermore, when the free radicals of type B flow through the gap between the rotating blade 102 and the fixed blade 123, if the free radicals of type B come into contact with the deposits accumulated in the outer cylinder 127, they impart significant energy to the deposits reacting with the free radicals of type B, forcibly breaking down the molecular chains on the surface of the deposits and decomposing them into low-molecular-weight, atomized gas. Then, the low-molecular-weight gas decomposed by the free radicals of type B, along with the free radical supply mechanism 201A, is also discharged to the outside through the exhaust port 133.

[0115] Furthermore, once the supply of type B free radicals from the free radical supply port 201a of the free radical supply mechanism 201B to the outer cylinder 127 for time t8 (1 minute) ends, the free radical supply valve 201b of the free radical supply mechanism 201B is switched from open to closed again, stopping the supply of type B free radicals from the free radical supply port 201a to the outer cylinder 127.

[0116] Therefore, the deposits accumulated inside the outer cylinder 127 can be particled and removed using free radicals of type A and type B, thereby reducing their size.

[0117] On the other hand, when the free radical supply valve 201b of the free radical supply mechanism 201B is switched from open to closed, the operation a in the chamber for time t1 (3 minutes) also ends.

[0118] Next, within the chamber, wafer cleaning and other operations b are initiated. In operation b, the chamber valve is opened for a period of time t2 (0.5 minutes), then rested for a period of time t3 (1 minute), and then opened again for a period of time t4 (0.5 minutes). Furthermore, during the period the chamber valve is open, the process gas within the chamber flows through the intake port 101 of the turbomolecular pump 100 into the outer cylinder 127. The process gas used within the chamber is compressed within the turbomolecular pump 100 (outer cylinder 127) and discharged from the exhaust port 133.

[0119] Thus, one cycle of operation on the chamber side and the turbomolecular pump 100 is completed, and thereafter, a series of actions are repeated until the system is stopped.

[0120] Therefore, according to the configuration of this embodiment, since free radicals of type A flow from the free radical supply port 201a of the free radical supply mechanism 201A and free radicals of type B flow from the free radical supply port 201a of the free radical supply mechanism 201B, multiple free radicals of types A and B are supplied into the outer cylinder 127. Therefore, even if the reaction of a single free radical (type A or type B) cannot be particled, free radicals of types A and type B can be supplied from the free radical supply port 201a of the free radical supply mechanism 201A and the free radical supply port 201a of the free radical supply mechanism 201B, respectively. By reacting the byproducts that have reacted with the free radicals of type A with the free radicals of type B, the accumulation of byproducts that cannot be particled by a single free radical is effectively particled into a gaseous state and discharged for cleaning.

[0121] Furthermore, by supplying free radicals into the turbomolecular pump 100, a sufficient amount of free radicals can be supplied to the turbomolecular pump 100 to enable the byproducts to react. Therefore, the degradation of the material of the turbomolecular pump 100 itself can be minimized, and the supply of gas required for the generation of free radicals can also be minimized.

[0122] Furthermore, in the turbomolecular pump 100 of this embodiment, such as Figure 1As shown, the free radical supply ports 201a of the free radical supply mechanisms 201A and 201B are positioned axially on the rotor shaft 113, closer to the exhaust port 133 than the fixed blade 102a closest to the intake port 101. That is, the free radical supply ports 201a are positioned between the fixed blade 123c and the rotating blade 102d. Therefore, if the motion of particles E and F, which are atomized after reacting with free radicals, is respectively... Figure 6 As schematically shown, particles E that collide with the rotating blade 102d are guided downwards towards the exhaust port 133. However, if some particles F that collide with the rotating blade 102d are bounced back towards the intake port 101 (chamber side), the bounced particles F collide with the fixed blade 123c disposed on the intake port 101 side, and their movement towards the intake port 101 side is stopped. Therefore, the main cause of defects in wafers, etc., caused by particles F bounced back towards the intake port 101 by the rotating blade 102d flowing back into the chamber can be eliminated.

[0123] Furthermore, the free radicals used for particle formation may degrade the structural components of the turbomolecular pump 100 (mainly aluminum, stainless steel, etc.), but in this embodiment, the free radical supply port 201a is directly mounted on the turbomolecular pump 100. Therefore, the minimum required free radicals can be directly supplied to the turbomolecular pump 100 without being affected by the structure from the chamber to the exhaust port 133.

[0124] In addition, the opening and closing of the free radical supply valve 201b is controlled, and the amount and timing of supplying free radicals from the free radical generation source 201c from the free radical supply port 201a are adjusted under the control of the controller 200. As a control method of the controller 200, methods such as (1) to (5) below can be considered.

[0125] (1) Based on the operating data representing the operating status of the turbomolecular pump 100, the controller 200 controls the opening and closing of the free radical supply valve 201b. In this control method, the controller 200 itself determines the status of the vacuum pump based on the operating data of the turbomolecular pump 100 and can automatically supply free radicals into the vacuum pump.

[0126] (2) When the current value of the motor 121, which drives the rotor shaft 113 to rotate and serves as operating data representing the operating status of the turbomolecular pump 100, exceeds a predetermined threshold, it is determined that byproduct accumulation is progressing and that a supply of free radicals is needed to clean up the byproducts. The controller 200 then controls the opening and closing of the free radical supply valve 201b. In this control method, when the current value of the motor 121, which drives the rotor shaft 113 to rotate and serves as operating data, exceeds a predetermined threshold, the controller 200 determines that a supply of free radicals is needed and can automatically supply free radicals into the turbomolecular pump 100.

[0127] (3) A method in which the controller 200 controls the opening and closing of the free radical supply valve 201b when the current value of the motor 121 driving the rotor shaft 113 to rotate, which is an operating data representing the operating status of the turbomolecular pump 100, is approximately equal to the current value of the motor 121 during no-load operation, which is stored in advance. In this control method, the controller 200 compares the current value of the motor 121 during no-load operation with the current value of the turbomolecular pump 100. When the current value is approximately equal to the current value of the motor 121 during no-load operation, it determines that there is no inflow of process gas, determines whether cleaning can be performed on the turbomolecular pump unit, and can automatically supply free radicals to the turbomolecular pump 100.

[0128] (4) When the pressure value, which is an operating data indicating the operating status of the turbomolecular pump 100, exceeds a predetermined threshold, the controller 200 determines that byproduct accumulation is progressing and that a supply of free radicals is needed to clean up the byproducts. In this control method, the controller 200 determines the state of the turbomolecular pump 100 based on the pressure value of the turbomolecular pump 100, determines whether a supply of free radicals is needed, and automatically supplies free radicals to the turbomolecular pump 100 when a supply is needed.

[0129] (5) When the pressure value of the turbomolecular pump 100, which is used as operating data to indicate the operating status of the turbomolecular pump 100, is approximately equal to the pressure value of the turbomolecular pump 100 under no-load operation that was previously stored, the aforementioned valve opening and closing control is performed. In this control method, the controller 200 compares the pressure value of the turbomolecular pump 100 under no-load operation with the current pressure value of the turbomolecular pump 100. When the pressure value is approximately equal to the pressure value of the turbomolecular pump 100 under no-load operation, it is determined that there is no inflow of process gas, and it is determined whether the turbomolecular pump unit can be cleaned, and free radicals can be automatically supplied to the turbomolecular pump 100.

[0130] In the turbomolecular pump 100 shown in Example 1, the case of supplying multiple types (type A, type B) of free radicals was described. However, when it is sufficient to supply only a single free radical of type A or type B, free radicals of the same type can also be supplied simultaneously from each free radical supply port 201a.

[0131] Figure 7 This is a diagram illustrating another embodiment of the turbomolecular pump 100, which is a vacuum pump according to the present invention. Figure 7 This is its longitudinal sectional view. Figure 7 The structure of the embodiment shown, in addition to Figure 1In addition to the free radical supply mechanisms 201A and 201B shown, the turbomolecular pump 100 also includes lower free radical supply mechanisms 201C and 201D, positioned a predetermined amount below the rotor shaft 113 relative to the free radical supply mechanisms 201A and 201B. Furthermore, the lower free radical supply mechanisms 201C and 201D differ only in their height relative to the outer cylinder 127. Figure 1 The free radical supply mechanism 201A and free radical supply mechanism 201B shown are basically the same in structure, so the same reference numerals are given to the same structural parts and repeated descriptions are omitted.

[0132] That is, in Figure 7 In the turbomolecular pump 100 shown as a vacuum pump, the radical supply ports 201a of the upper radical supply mechanism 201A and the radical supply port 201a of the radical supply mechanism 201B are positioned between the fixed blade 123c and the rotating blade 102d. This is located on the exhaust port 133 side of the fixed blade 102a, which is closest to the intake port 101, in the axial direction of the rotor shaft 113. On the other hand, the radical supply ports 201a of the lower radical supply mechanism 201C and the radical supply mechanism 201D are also positioned on the exhaust port 133 side of the rotating blade 102j, which is furthest from the intake port 101, in the axial direction of the rotor shaft 113, between the rotating blade 102j and the threaded spacer 131.

[0133] Figure 7 The free radical supply mechanisms 201A and 201B on the upper side and 201C and 201D on the lower side of the turbomolecular pump 100 shown are controlled by the controller 200, and Figure 5 Similarly, in the time diagram shown, during operation a, different types of free radicals A, B, C, and D are flowed in a predetermined order to perform free radical treatment during operation a, thereby effectively granulating and discharging the accumulation of byproducts that can be granulated by using multiple types of free radicals through stages.

[0134] exist Figure 7 In the case of the embodiment shown, it is possible to obtain the same as Figure 1The illustrated embodiment exhibits the same effect. Furthermore, some free radicals have longer durations of effect while others have shorter durations. Therefore, if free radicals of type A and type B, which have longer lifetimes (durations of effect duration), are used in combination with free radicals of type C and type D, which have shorter lifetimes than type A and type B, then the lifetimes of free radicals of type A, type B, type C, and type D can be made equal, allowing for efficient use.

[0135] Furthermore, in the above embodiments, the free radical generating power sources of free radical supply mechanisms 201A, 201B, 201C, and 201D, as well as the power supply within the cavity of the semiconductor manufacturing apparatus, can be shared. Moreover, by sharing the free radical generating power sources of free radical supply mechanisms 201A, 201B, 201C, and 201D, and the power supply within the cavity of the semiconductor manufacturing apparatus, the number of power sources is reduced, and cost or space reduction effects can be expected.

[0136] Furthermore, various modifications can be made to this invention without departing from its spirit, and this invention certainly relates to such modified forms.

[0137] Explanation of reference numerals in the attached figures

[0138] 100: Turbomolecular pump

[0139] 101: Intake port

[0140] 102: Rotating blade

[0141] 102a: Fixed blade

[0142] 102c: Rotary blade

[0143] 102d: Rotating blade

[0144] 102j: Rotary blade

[0145] 103: Solid of Revolution

[0146] 103b: Cylindrical section

[0147] 104: Upper radial electromagnet

[0148] 105: Lower radial electromagnet

[0149] 106A: Axial electromagnet

[0150] 106B: Axial electromagnet

[0151] 107: Upper radial sensor

[0152] 108: Lower radial sensor

[0153] 109: Axial sensor

[0154] 111: Metal disc

[0155] 113: Rotor shaft

[0156] 120: Protect the bearing

[0157] 121: Motor

[0158] 122: Stator column

[0159] 123: Fixed blades

[0160] 123a: Fixed blade

[0161] 123b: Fixed blade

[0162] 123c: Fixed blade

[0163] 123d: Fixed blade

[0164] 123e: Fixed blade

[0165] 125: Fixed blade spacer

[0166] 127: Outer cylinder (shell)

[0167] 129: Base section

[0168] 131: Threaded spacer

[0169] 131a: Threaded groove

[0170] 133: Exhaust port

[0171] 134: Purge gas supply port

[0172] 141: Electronic Circuits Department

[0173] 143: Substrate

[0174] 145: Bottom Cover

[0175] 149: Water-cooled pipe

[0176] 150: Amplifier Circuit

[0177] 151: Electromagnet winding

[0178] 161: Transistor

[0179] 161a: Cathode terminal

[0180] 161b: Anode terminal

[0181] 162: Transistor

[0182] 162a: Cathode terminal

[0183] 162b: Anode terminal

[0184] 165: Diode

[0185] 165a: Cathode terminal

[0186] 165b: Anode terminal

[0187] 166: Diode

[0188] 166a: Cathode terminal

[0189] 166b: Anode terminal

[0190] 171: Power Supply

[0191] 171a: Positive electrode

[0192] 171b: Negative electrode

[0193] 181: Current Detection Circuit

[0194] 191: Amplifier Control Circuit

[0195] 191a: Gate drive signal

[0196] 191b: Gate drive signal

[0197] 191c: Current detection signal

[0198] 200: Controller

[0199] 201: Free Radical Supply Mechanism

[0200] 201A: Free Radical Supply Mechanism

[0201] 201B: Free Radical Supply Mechanism

[0202] 201C: Free Radical Supply Mechanism

[0203] 201D: Free Radical Supply Mechanism

[0204] 201a: Free radical supply port

[0205] 201b: Valve

[0206] 201c: Source of free radicals

[0207] A: Types

[0208] B: Types

[0209] E: Particle

[0210] F: Particle

[0211] T: Processing time

[0212] Tp1: Pulse Width Time

[0213] Tp2: Pulse Width Time

[0214] Ts: Control cycle

[0215] c: type

[0216] d: type

[0217] iL: Electromagnetic current

[0218] iLmax: Current value

[0219] iLmin: Current value.

Claims

1. A vacuum pump, comprising: The housing has an air intake and an air exhaust port; The rotor shaft is rotatably supported inside the aforementioned housing; and A rotating body having rotating blades fixed to the aforementioned rotor shaft, capable of rotating together with the aforementioned rotor shaft; Its features are, It has a first free radical supply mechanism, a second free radical supply mechanism, and a controller. The first free radical supply mechanism is capable of supplying a first free radical into the aforementioned housing, and includes: a first free radical supply port disposed in the aforementioned housing, a first free radical generation source for generating the aforementioned first free radical, and a first valve disposed between the aforementioned first free radical generation source and the aforementioned first free radical supply port. The aforementioned second radical supply mechanism is capable of supplying a second radical, which is different from the aforementioned first radical, into the aforementioned housing. It is a separate mechanism from the aforementioned first radical supply mechanism and includes: a second radical supply port disposed in the aforementioned housing; a second radical generation source that generates the aforementioned second radical and is a radical generation source other than the aforementioned first radical generation source; and a second valve disposed between the aforementioned second radical generation source and the aforementioned second radical supply port. The aforementioned controller is configured to open the aforementioned first valve during a first period when the valve between the aforementioned vacuum pump and the processing chamber is closed, close the aforementioned first valve after the aforementioned first period, and open the aforementioned second valve during a second period when the aforementioned first valve is closed and the valve between the aforementioned vacuum pump and the processing chamber is closed. The first period is a period sufficient for the aforementioned first free radical, which requires multiple reaction steps for decomposition, to react with the aforementioned vacuum pump deposit. The second period is a period sufficient for the aforementioned second free radical to react with the aforementioned deposit that has not reacted with the aforementioned first free radical.

2. The vacuum pump according to claim 1, characterized in that, The aforementioned first free radical supply mechanism has a first power source that drives the aforementioned first free radical generation source, and the aforementioned second free radical supply mechanism has a second power source that drives the aforementioned second free radical generation source.

3. The vacuum pump according to claim 2, characterized in that, The first power supply and at least a portion of the second power supply are shared with the power supply for pump control.

4. The vacuum pump according to claim 2, characterized in that, The first power source and at least a portion thereof are shared with the plasma generation power source of the chamber.

5. The vacuum pump according to claim 2, characterized in that, The aforementioned first free radical generation source and the aforementioned second free radical generation source have replaceable electrodes, and the aforementioned first power supply and the aforementioned second power supply have variable voltage output functions. The generation of the aforementioned first free radical and the aforementioned second free radical can be achieved by replacing the aforementioned electrodes and adjusting the voltage output of the aforementioned first power supply and the aforementioned second power supply.

6. The vacuum pump according to any one of claims 1 to 5, characterized in that, The aforementioned first free radical supply port and the aforementioned second free radical supply port are respectively arranged in the axial direction of the aforementioned rotor shaft at a position equidistant from the aforementioned intake port.

7. The vacuum pump according to claim 1, characterized in that, The aforementioned vacuum pump also includes a controller for controlling the opening and closing of the aforementioned first valve and the aforementioned second valve.

8. The vacuum pump according to claim 7, characterized in that, The aforementioned controller controls the opening and closing of the aforementioned first valve and the aforementioned second valve based on operating data indicating the operating status of the aforementioned vacuum pump.

9. The vacuum pump according to claim 8, characterized in that, When the current value of the motor that drives the rotation of the rotor shaft, which is the aforementioned operating data, exceeds a predetermined threshold, the aforementioned controller determines that the accumulation of byproducts is progressing and that the supply of the aforementioned first free radical and the aforementioned second free radical is required for the cleaning of the byproducts.

10. The vacuum pump according to claim 8, characterized in that, When the current value of the motor that drives the rotor shaft to rotate, which is the aforementioned operating data, is equal to the current value of the aforementioned motor when it is operating under no load, the aforementioned controller performs the opening and closing control of the aforementioned first valve and the aforementioned second valve.

11. The vacuum pump according to claim 8, characterized in that, When the pressure value of the aforementioned vacuum pump, which is the aforementioned operating data, exceeds a predetermined threshold, the aforementioned controller determines that the accumulation of byproducts is progressing and that the supply of the aforementioned first free radical and the aforementioned second free radical is required for the cleaning of the byproducts.

12. The vacuum pump according to claim 8, characterized in that, When the pressure value of the aforementioned vacuum pump, which is the aforementioned operating data, is equal to the pressure value of the aforementioned vacuum pump during no-load operation that is pre-stored, the aforementioned controller performs the opening and closing control of the aforementioned first valve and the aforementioned second valve.

13. A cleaning system for a vacuum pump, wherein the vacuum pump comprises: The housing has an air intake and an air exhaust port; The rotor shaft is rotatably supported inside the aforementioned housing; and A rotating body having rotating blades fixed to the aforementioned rotor shaft, capable of rotating together with the aforementioned rotor shaft; The aforementioned vacuum pump cleaning system is characterized by, It has a first free radical supply mechanism, a second free radical supply mechanism, and a controller. The first free radical supply mechanism is capable of supplying a first free radical into the aforementioned housing, and includes: a first free radical supply port disposed in the aforementioned housing, a first free radical generation source for generating the aforementioned first free radical, and a first valve disposed between the aforementioned first free radical generation source and the aforementioned first free radical supply port. The aforementioned second radical supply mechanism is capable of supplying a second radical, which is different from the aforementioned first radical, into the aforementioned housing. It is a separate mechanism from the aforementioned first radical supply mechanism and includes: a second radical supply port disposed in the aforementioned housing; a second radical generation source that generates the aforementioned second radical and is a radical generation source other than the aforementioned first radical generation source; and a second valve disposed between the aforementioned second radical generation source and the aforementioned second radical supply port. The aforementioned controller is configured to open the aforementioned first valve during a first period when the valve between the aforementioned vacuum pump and the processing chamber is closed, close the aforementioned first valve after the aforementioned first period, and open the aforementioned second valve during a second period when the aforementioned first valve is closed and the valve between the aforementioned vacuum pump and the processing chamber is closed. The first period is a period sufficient for the aforementioned first free radical, which requires multiple reaction steps for decomposition, to react with the aforementioned vacuum pump deposit. The second period is a period sufficient for the aforementioned second free radical to react with the aforementioned deposit that has not reacted with the aforementioned first free radical.

Images