WO2023162985A1

WO2023162985A1 - Vacuum discharge system

Info

Publication number: WO2023162985A1
Application number: PCT/JP2023/006256
Authority: WO
Inventors: 正幸橋本; 好伸大立; 靖前島; 勉高阿田
Original assignee: エドワーズ株式会社
Priority date: 2022-02-28
Filing date: 2023-02-21
Publication date: 2023-08-31
Also published as: GB202208028D0; JP2023125364A; TW202346716A

Abstract

[Problem] To propose a vacuum discharge system which causes a product derived from process gas to be less likely deposited in a turbo molecular pump and which is capable of effectively using a space required for equipment installation. [Solution] A vacuum discharge system 200 is characterized by comprising: a plurality of turbo molecular pumps 100 each of which includes a turbo molecular pump mechanism which discharges gas molecules from a discharge port 133 by an interaction between a plurality of stages of rotor blades 102 and a plurality of stages of stator blades 123 and which does not include a thread groove pump mechanism; a discharge pipe 204 including a unified pipe portion 206 to which each of the discharge ports 133 is connected; and a back pump 203 which is connected to the discharge pipe 204 and discharges the gas molecules via the unified pipe portion 206.

Description

Vacuum exhaust system

The present invention relates to an evacuation system.

Etching, ALD (Atomic Layer Deposition, atomic layer deposition technology), CVD (Chemical Vapor Deposition, chemical vapor deposition technology), etc. are used in surface treatment for forming thin films on wafer surfaces in semiconductor manufacturing.

Etching for semiconductor manufacturing and the like is usually performed with the substrate placed in the chamber and the chamber in a vacuum atmosphere, so a vacuum exhaust system connected to the chamber is required in the semiconductor manufacturing process. In addition to exhaust pipes connected to the chamber, the vacuum pumping system includes back pumps (dry vacuum pumps), booster pumps (mechanical booster pumps), and turbomolecular pumps that are connected to the exhaust pipes to evacuate the chamber. It is configured including a device.

As shown in Patent Document 1, a turbo-molecular pump is composed of a turbo-molecular pump mechanism composed of multiple stages of rotary blades and multiple stages of fixed blades on the exhaust upstream side, and a screw groove pump provided on the exhaust downstream side. Mechanism.

Here, one embodiment of the evacuation system provided in the building will be described with reference to FIG. In providing the vacuum exhaust system 500 in the building as illustrated, for example, a clean room CR is provided on the upper floor UF, and

chambers

501A, 501B, 501C, . . . , 502C . As illustrated,

booster pumps

503A, 503B, 503C, . . . and

back pumps

504A, 504B, 504C, . Common. The booster pumps 503A, . . . may be installed inside the clean room CR. Here, the chambers 501A . . . , turbo molecular pumps 502A . The chambers 501A, . . . , booster pumps 503A, . . . , and back pumps 504A . Valves (

first valves

507A, 507B, 507C . . . ,

second valves

508A, 508B, 508C . 509A, 509B, 509C...,

fourth valves

510A, 510B, 510C...) are provided.

The reason why the vacuum exhaust system 500 is installed in such an arrangement is that a high degree of cleanliness is required when forming a thin film, and the clean room equipment and maintenance costs are high to achieve this. This is to reduce the cost by minimizing the area of the clean room. The booster pumps 503A and back pumps 504A are arranged directly under the chambers 501A and the like because the lengths of the exhaust pipes 505A and the roughing pipes 506A are reduced. This is to make the conductance as large as possible by shortening it.

In addition, equipment for manufacturing semiconductors, etc. is installed in a dense state as shown in Patent Document 2 in order to reduce the installation space as much as possible and to allow many equipment to be installed in the same space.

JP 2013-079602 A JP 2017-079329 A

By the way, when the process gas is exhausted, the temperature and pressure of the gas decrease, the gas sublimates, and solid products accumulate in the turbomolecular pump, narrowing the pump flow path and reducing the performance of the turbomolecular pump. may decrease. Such a phenomenon is likely to occur particularly in a thread groove pump mechanism having a narrow pump flow path. For this reason, as disclosed in Patent Document 1, a heating device for heating the pump body and a cooling device for cooling the pump body are controlled to make it difficult for the product to deposit. However, the cost will be high if it is configured so that such control can be performed. In addition, in recent semiconductor manufacturing, the flow rate of process gas is increasing, so even if these mechanisms are used, products tend to accumulate.

In addition, although manufacturing equipment for semiconductors and the like is installed in a dense state as in Patent Document 2, in order to further reduce costs and improve production efficiency, it is necessary to further improve the effective use of installation space. .

In view of these points, the present invention makes it difficult for products derived from the process gas to accumulate in the turbomolecular pump without using the conventionally used heating device or cooling device, and furthermore, it is necessary to install the manufacturing equipment. An object of the present invention is to provide an evacuation system that can effectively utilize space.

The vacuum exhaust system of the present invention includes a turbo-molecular pump mechanism that exhausts gas molecules from an exhaust port by interaction between multiple stages of rotor blades and multiple stages of fixed blades. a molecular pump; an exhaust pipe having an integrated pipe section to which each of the exhaust ports is connected; and a back pump connected to the exhaust pipe for exhausting the gas molecules through the integrated pipe section. Characterized by

In such a vacuum exhaust system, a booster pump that assists the exhaust performance of the back pump is connected between the integrated pipe portion of the exhaust pipe and the back pump, and the number of the booster pumps is equal to the number of the turbo molecule Preferably less than the number of pumps.

Further, it is preferable that the booster pump is arranged side by side with respect to the turbo-molecular pump, and the integrated piping section is arranged at a position avoiding directly under the turbo-molecular pump.

It is preferable that a backup booster pump that assists the exhaust performance of the back pump is further connected between the integrated pipe portion and the back pump in the exhaust pipe.

Further, it is preferable that a backup pump for exhausting the gas molecules is further connected to the exhaust pipe through the integrated pipe section.

In the evacuation system of the present invention, the turbomolecular pump does not have a thread groove pump mechanism, so the product is less likely to accumulate in the pump. A reduction in exhaust performance of the turbo-molecular pump due to the omission of the thread groove pump mechanism can be compensated for by the back pump. In addition, conventional exhaust pipes connect turbo-molecular pumps and back pumps to each chamber, respectively, and the number of chambers is the same as the number of turbo-molecular pumps and back pumps. The piping has an integrated piping section to which each of a plurality of turbomolecular pumps is connected, and the back pump exhaust is configured to be performed via the integrated piping section, so the number of back pumps can be reduced. can be done. Therefore, the space that was conventionally required for installing the back pump can be saved, and the space required for installing the manufacturing equipment can be effectively utilized.

1 is a longitudinal sectional view schematically showing an embodiment of a vacuum pump included in an evacuation system according to the present invention; FIG. 2 is a circuit diagram of an amplifier circuit of the vacuum pump shown in FIG. 1; FIG. 4 is a time chart showing control when a current command value is greater than a detected value; 4 is a time chart showing control when a current command value is smaller than a detected value; 1 schematically shows an embodiment of an evacuation system according to the invention; FIG. 6A and 6B are diagrams schematically showing the periphery of the integrated piping section of the evacuation system shown in FIG. 5, where (a) is a plan view and (b) is a side view; FIG. 6 is a diagram showing a modification of the evacuation system shown in FIG. 5; 1 is a diagram schematically showing a conventional evacuation system; FIG.

An embodiment of the evacuation system according to the present invention will be described below with reference to the drawings. First, the turbomolecular pump included in this evacuation system will be described with reference to FIGS. 1 to 4. FIG.

A longitudinal sectional view of this turbo-molecular pump 100 is shown in FIG. In FIG. 1, the turbomolecular pump 100 is provided with an intake port 101 at the upper end of a cylindrical outer cylinder 127 extending along the central axis CA. Inside the outer cylinder 127, a rotating body 103 having a plurality of rotating blades 102 (102a, 102b, 102c, . is provided. A rotor shaft 113 is attached to the center of the rotor 103, and the rotor shaft 113 is levitated in the air and position-controlled by, for example, a 5-axis control magnetic bearing. The rotor 103 is generally made of metal such as aluminum or aluminum alloy.

The upper radial electromagnet 104 has four electromagnets 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 the upper radial electromagnets 104, respectively. The upper radial sensor 107 is, for example, an inductance sensor or an eddy current sensor having a conductive winding, and detects the position of the rotor shaft 113 based on the change in the inductance of this conductive winding, which changes according to the position of the rotor shaft 113 . to detect The upper radial sensor 107 is configured to detect the radial displacement of the rotor shaft 113, that is, the rotating body 103 fixed thereto, and send it to a control device (not shown).

In this control device, for example, a compensation circuit having a PID adjustment 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, and the amplifier shown in FIG. A circuit 150 (described later) 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 .

The rotor shaft 113 is made of a high magnetic permeability material (iron, stainless steel, etc.) or the like, and is attracted by the magnetic force of the upper radial electromagnet 104 . Such adjustments are made independently in the X-axis direction and the Y-axis direction. In addition, 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 so that the lower radial position of the rotor shaft 113 is set to the upper radial position. adjusted in the same way.

Furthermore, the

axial electromagnets

106A and 106B are arranged so as to vertically sandwich a disk-shaped metal disk 111 provided below the rotor shaft 113 . The metal disk 111 is made of a high magnetic permeability material such as iron. An axial sensor 109 is provided to detect axial displacement of the rotor shaft 113 and is configured to send its axial position signal to the controller.

Then, in the control device, a compensation circuit having, for example, a PID adjustment function generates excitation control command signals for the

axial electromagnets

106A and 106B based on the axial position signal detected by the axial sensor 109. Then, the amplifier circuit 150 controls the excitation of the axial electromagnet 106A and the axial electromagnet 106B based on these excitation control command signals, so that the axial electromagnet 106A attracts the metal disk 111 upward by magnetic force, The axial electromagnet 106B attracts the metal disk 111 downward, and the axial position of the rotor shaft 113 is adjusted.

In this manner, the control device appropriately adjusts the magnetic force exerted on the metal disk 111 by the

axial electromagnets

106A and 106B, magnetically levitates the rotor shaft 113 in the axial direction, and holds the rotor shaft 113 in the space without contact. there is The amplifier circuit 150 that controls the excitation of the upper radial electromagnet 104, the lower radial electromagnet 105, and the

axial electromagnets

106A and 106B will be described later.

On the other hand, the motor 121 has a plurality of magnetic poles circumferentially arranged to surround the rotor shaft 113 . Each magnetic pole is controlled by a control device so as to rotationally drive the rotor shaft 113 via an electromagnetic force acting between the magnetic poles and the rotor shaft 113 . Further, the motor 121 incorporates a rotation speed sensor (not shown) such as a Hall element, resolver, encoder, etc., and the rotation speed of the rotor shaft 113 is detected by the detection signal of this rotation speed sensor.

Furthermore, a phase sensor (not shown) is attached, for example, near the lower radial direction sensor 108 to detect the phase of rotation of the rotor shaft 113 . The control device detects the position of the magnetic pole using both the detection signals from the phase sensor and the rotational speed sensor.

A plurality of fixed wings 123 (123a, 123b, 123c...) are arranged with a slight gap from the rotary wings 102 (102a, 102b, 102c...). The rotor blades 102 (102a, 102b, 102c, . . . ) are inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to move molecules of the exhaust gas downward by collision. there is The fixed wings 123 (123a, 123b, 123c, . . . ) are made of metal such as aluminum, iron, stainless steel, or copper, or metal such as an alloy containing these metals as components.

Similarly, the fixed blades 123 are also inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged inwardly of the outer cylinder 127 in a staggered manner with the stages of the rotary blades 102. ing. The outer peripheral end of the fixed wing 123 is supported by being inserted between a plurality of stacked fixed wing spacers 125 (125a, 125b, 125c, . . . ).

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 circumference of the stationary blade spacer 125 with a small gap therebetween. A base portion 129 is provided at the bottom of the outer cylinder 127 . The base portion 129 is formed with an exhaust port 133 that opens laterally so as to be orthogonal to the central axis CA, and the exhaust port 133 is connected to an evacuation system, which will be described later. Exhaust gas that has entered the intake port 101 from the chamber (vacuum chamber) side and has been transferred to the base portion 129 is sent to the exhaust port 133 .

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

In such a configuration, when the rotor shaft 113 and the rotor shaft 113 are driven to rotate by the motor 121 , the rotor blades 102 and the fixed blades 123 act to suck exhaust gas from the chamber through the intake port 101 . The rotation speed of the rotor blade 102 is usually 20000-90000 rpm, and the peripheral speed at the tip of the rotor blade 102 reaches 200-400 m/s. Exhaust gas sucked from the intake port 101 passes between the rotor blade 102 and the fixed blade 123 , is transferred to the base portion 129 , and is discharged from the exhaust port 133 . At this time, the temperature of the rotor blades 102 rises due to frictional heat generated when the exhaust gas contacts the rotor blades 102, conduction of heat generated by the motor 121, and the like. It is transmitted to the stationary blade 123 side by conduction by molecules or the like.

The fixed blade spacers 125 are joined to each other at their outer peripheral portions, and transmit the heat received by the fixed blades 123 from the rotary blades 102 and the frictional heat generated when the exhaust gas contacts the fixed blades 123 to the outside.

By the way, in the conventional turbo-molecular pump, a screw groove pump mechanism is provided below the lowermost rotor blade 102 and the fixed blade 123 so that it can be operated even when the back pressure is high. Exhaust gas sucked from the intake port 101 by the fixed wing 123 is discharged from the exhaust port 133 via this thread groove pump mechanism. On the other hand, the turbo-molecular pump 100 of the present embodiment does not include such a screw groove pump mechanism, and pumps gas molecules from the exhaust port 133 using only the turbo-molecular pump mechanism including the rotor blades 102 and the fixed blades 123. configured to exhaust.

Further, depending on the application of the turbo-molecular pump 100, the gas sucked from the intake port 101 may move the upper radial electromagnet 104, the upper radial sensor 107, the motor 121, the lower radial electromagnet 105, the lower radial sensor 108, the shaft The electrical section is surrounded by a stator column 122 so as not to intrude into the electrical section composed of the

directional electromagnets

106A and 106B, the axial direction sensor 109, etc., and the interior of the stator column 122 is maintained at a predetermined pressure with purge gas. It may drip.

In this case, a pipe (not shown) is arranged in the base portion 129, and the purge gas is introduced through this pipe. The introduced purge gas is delivered 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 blade 102 .

Here, the turbo-molecular pump 100 requires model identification and control based on individually adjusted unique parameters (for example, various characteristics corresponding to the model). In order to store the control parameters, the turbomolecular pump 100 has an electronic circuit section 141 in its body. The electronic circuit section 141 includes a semiconductor memory such as an EEP-ROM, electronic components such as semiconductor elements for accessing the same, a board 143 for mounting them, and the like. The electronic circuit section 141 is accommodated, for example, below a rotational speed sensor (not shown) near the center of a base section 129 that constitutes the lower portion of the turbo-molecular pump 100 and is closed by an airtight bottom cover 145 .

In the semiconductor manufacturing process, some of the 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. be. Inside the turbomolecular pump 100 , the pressure of the exhaust gas is lowest at the inlet 101 and highest at the outlet 133 . When the process gas is transported from the inlet 101 to the outlet 133, if its pressure becomes higher than a predetermined value or its temperature becomes lower than a predetermined value, the process gas becomes solid and turbo molecules are formed. It adheres and deposits inside the pump 100 .

For example, when SiCl4 is used as a process gas in an Al etching apparatus, a solid product (eg, AlCl3 ) is precipitated and deposited inside the turbo-molecular pump 100 from the vapor pressure curve. As a result, when deposits of the process gas accumulate inside the turbo-molecular pump 100 , the deposits narrow the pump flow path and cause the performance of the turbo-molecular pump 100 to deteriorate. In conventional turbo-molecular pumps, deposits tend to accumulate in the screw groove pump mechanism located near the high-pressure exhaust port, which tends to lead to performance deterioration.

Therefore, in order to solve this problem, conventionally, a heater (not shown) or an annular water-cooling tube (not shown) is wound around the outer periphery of the base portion or the like, and a temperature sensor (for example, a thermistor) (not shown) is embedded in the base portion. Heating of the heater and cooling by water cooling pipes are controlled (hereinafter referred to as TMS: Temperature Management System) so as to keep the temperature of the base portion at a constant high temperature (set temperature) based on the signal of . However, providing these members increases the cost. In particular, in recent semiconductor manufacturing, the flow rate of process gas is increasing, so even when the TMS technology is applied, deposits are likely to accumulate in the thread groove pump mechanism. On the other hand, since the turbo-molecular pump 100 of the present embodiment does not have a screw groove pump mechanism, deposition of precipitates in the turbo-molecular pump 100 can be suppressed, and the cost can be reduced by omitting members related to TMS. can be done.

Next, regarding the turbo-molecular pump 100 configured in this way, the amplifier circuit 150 that controls the excitation of the upper radial electromagnet 104, the lower radial electromagnet 105, and the

axial electromagnets

106A and 106B will be described. A circuit diagram of this amplifier circuit 150 is shown in FIG.

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

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

On the other hand, the diode 165 for current regeneration has a cathode terminal 165a connected to one end of the electromagnet winding 151 and an 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 the current detection circuit 181. It has become so. The current detection circuit 181 is composed of, for example, a Hall sensor type current sensor or an electric resistance element.

The amplifier circuit 150 configured as described above corresponds to one electromagnet. Therefore, if 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 of the electromagnets, and ten amplifier circuits are provided for the power source 171. 150 are connected in parallel.

Further, the amplifier control circuit 191 is composed of, for example, a digital signal processor section (hereinafter referred to as a DSP section) (not shown) of the control device. It has become.

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

It is necessary to control the position of the rotating body 103 at high speed and with a strong force when the rotating body 103 passes through the resonance point during acceleration operation of the rotation speed or when disturbance occurs during constant speed operation. . Therefore, a high voltage of about 50 V, for example, is used as the power source 171 so that the current flowing through the electromagnet winding 151 can be rapidly increased (or decreased). A capacitor is usually connected between the positive electrode 171a and the negative electrode 171b of the power source 171 for stabilizing the power source 171 (not shown).

In such a configuration, when both transistors 161 and 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.

Also, when one of the transistors 161 and 162 is turned on and the other is turned off, a so-called flywheel current is held. By passing the flywheel current through the amplifier circuit 150 in this way, the hysteresis loss in the amplifier circuit 150 can be reduced, and the power consumption of the entire circuit can be suppressed. Further, by controlling the transistors 161 and 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.

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

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

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

Next, an evacuation system 200 including the turbomolecular pump 100 described above will be described with reference to FIG. The vacuum exhaust system 200 of this embodiment has a clean room CR provided on the upper floor UF, a plurality of

chambers

201A, 201B, 201C, . . . and the same number of

turbomolecular pumps

100A, 100B, 100C . The evacuation system 200 also includes one booster pump 202 installed outside the clean room CR on the upper floor UF and one back pump 203 installed on the lower floor LF where the clean room CR is not provided. is composed of

The booster pump 202 is also called a mechanical booster pump, and the ultimate vacuum is about 0.01 to 10 Pa as an example. The back pump 203 is also called a dry vacuum pump, and the ultimate degree of vacuum is, for example, about 1 kPa. Booster pump 202 is often a Roots positive displacement vacuum pump. Compared to turbomolecular pumps (especially screw groove pump mechanisms), Roots-type positive displacement vacuum pumps have a large inertia of the rotating body and operate at low speed and high torque, so there is a margin to maintain performance against product buildup. is large. The back pump 203 is often a positive displacement dry vacuum pump of roots type, claw type or screw type. Compared to turbomolecular pumps (particularly screw groove pump mechanisms), these pumps have a large margin for maintaining performance against product buildup, similar to the booster pump 202 .

The chambers 201A . . . , the turbomolecular pump 100A . The chambers 201A and the back pump 203 are connected to each other by a roughing pipe 205 in addition to the exhaust pipe 204 .

Here, the exhaust pipe 204 will be described in detail. The exhaust pipe 204 of this embodiment includes a horizontally extending integrated pipe portion 206 as shown in FIG. A plurality of

connection ports

207A, 207B, 207C, . The turbo-molecular pumps 100A . The exhaust ports 133A of the turbomolecular pumps 100A are connected to the connection ports 207A. The booster pump 202 is installed side by side with the turbo-molecular pumps 100A . It should be noted that the one end portion of the integrated pipe section 206 and the booster pump 202 may not be directly connected, but may be connected via a pipe that constitutes the exhaust pipe 204 .

In addition, the exhaust pipe 204 includes first valves 208A... between the chambers 201A... and the turbomolecular pumps 100A..., as shown in FIG. Further, the exhaust pipe 204 is provided with a second valve 209 and a third valve 210 at the portion located on the upper floor UF and the portion located on the lower floor LF, respectively, between the booster pump 202 and the back pump 203 .

As shown in FIG. 5, the roughing pipe 205 is branched into a plurality of pipes on the upstream side of the exhaust gas, and is combined into a single pipe on the downstream side of the exhaust gas. A plurality of branched portions of the roughing pipe 205 are connected to chambers 201A, respectively, and

fourth valves

211A, 211B, 211C, . A united portion of the roughing pipe 205 is connected to the back pump 203, and a fifth valve 212 is provided at the united portion.

The above-described vacuum evacuation system 200 is configured such that evacuation from the turbomolecular pumps 100A . Since it is not necessary to provide a booster pump and a back pump for each chamber as in the exhaust system 500, the number of booster pumps 202 and back pumps 203 can be reduced. Therefore, the space required for installing the booster pump and the back pump in the conventional evacuation system 500 can be saved, so that the space in the building in which the evacuation system 200 is installed can be effectively utilized. In addition, the conventional vacuum evacuation system 500 requires a plurality of evacuation pipes 505A to connect the turbo molecular pumps 502A and the booster pumps 503A. In the system 200, since the pipes are integrated into one integrated pipe section 206, more space can be saved in this respect as well. By connecting the turbomolecular pumps 100A, . Also, if the integrated piping section 206 is arranged directly below the turbo molecular pumps 100A, etc., the turbo molecular pumps 100A, . . . However, by arranging the integrated piping section 206 at a position that avoids directly under the turbo-molecular pumps 100A, . . . as in the present embodiment, the height can be suppressed.

In order to make the chambers 201A . The chambers 201A under atmospheric pressure are decompressed through the air pipe 205. After the pressure in the chambers 201A is reduced to a predetermined pressure, the fourth valves 211A and the fifth valve 212 are closed, and the first valve 208A, the second valve 209 and the third valve are closed. 210 is opened, and the turbomolecular pumps 100A, . Although the turbo-molecular pumps 100A of the present embodiment are not provided with the thread groove pump mechanism as described above, the deterioration of the exhaust performance of the turbo-molecular pump 100A due to the omission of the thread groove pump mechanism may be caused by the booster. It can be supplemented by pump 202 and back pump 203 .

The evacuation system 200 described above may be configured like the evacuation system 250 shown in FIG. The evacuation system 250 of this embodiment further includes a backup booster pump 251 and a backup back pump 252 in addition to the evacuation system 200 . The backup booster pump 251 is installed on the upper floor UF of the same layer as the booster pump 202 and outside the clean room CR, and the backup back pump 252 is installed on the lower floor LF of the same layer as the back pump 203 . The backup booster pump 251 is connected to the integrated piping section 206 via a sixth valve 253, and is connected via a seventh valve 254 to the exhaust downstream side of the booster pump 202 in the exhaust piping 204. . The backup back pump 252 is connected to the exhaust pipe 204 via the eighth valve 255 and is connected to the roughing pipe 205 via the ninth valve 256 .

According to the vacuum evacuation system 250, when the booster pump 202 malfunctions, the booster pump 202 is stopped and the sixth valve 253 and the seventh valve 254 are opened to drive the backup booster pump 251. As a result, the operation of the evacuation system 250 can be continued without stopping for a long time. When the back pump 203 malfunctions and the roughing pipe 205 is to be decompressed, the back pump 203 is stopped, the fifth valve 212 is closed, and the ninth valve 256 is opened to open the backup back pump. Drive the pump 252 . Further, when reducing the pressure in the exhaust pipe 204, the back pump 203 is stopped, the eighth valve 255 is opened, and the backup back pump 252 is driven. By executing such a procedure, even if the back pump 203 malfunctions, the operation of the vacuum exhaust system 250 can be continued without a long period of stoppage.

Although one embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and unless otherwise limited by the above description, the spirit of the present invention described in the claims Various modifications, changes, and combinations are possible within the scope of. Moreover, the effects of the above-described embodiments are merely examples of the effects produced by the present invention, and do not mean that the effects of the present invention are limited to the above effects.

For example, the booster pumps 202 provided in the

evacuation systems

200 and 250 supplement the evacuation performance of the back pumps 203 . Therefore, the booster pump 202 may be omitted if the back pump 203 alone can sufficiently evacuate. Also, the number of booster pumps 202 used in the

evacuation systems

200 and 250 should be less than the number of turbomolecular pumps 100, and the number is not limited to one as described above, and may be plural.

100: turbomolecular pump 102: rotor blade 123: fixed blade 133: exhaust port 200, 250: vacuum exhaust system 202: booster pump 203: back pump 204: exhaust pipe 206: integrated pipe section 251: backup booster pump 252: backup back pump for

Claims

a plurality of turbo-molecular pumps having a turbo-molecular pump mechanism for exhausting gas molecules from an exhaust port by interaction between a plurality of stages of rotor blades and a plurality of stages of stationary blades, but not having a screw groove pump mechanism;
an exhaust pipe having an integrated pipe section to which each of the exhaust ports is connected;
and a back pump that is connected to the exhaust pipe and exhausts the gas molecules through the integrated pipe section.
A booster pump that assists the exhaust performance of the back pump is connected between the integrated pipe portion and the back pump in the exhaust pipe,
2. The evacuation system according to claim 1, wherein the number of said booster pumps is less than the number of said turbomolecular pumps.
the booster pump is arranged side by side with the turbomolecular pump;
3. The evacuation system according to claim 2, wherein the integrated piping section is arranged at a position avoiding directly below the turbo-molecular pump.
4. The vacuum exhaust system according to claim 2, wherein a backup booster pump for assisting the exhaust performance of the back pump is further connected between the integrated piping section and the back pump in the exhaust piping. system.
5. The vacuum evacuation system according to claim 1, further comprising a backup pump for evacuating the gas molecules through the integrated piping section, which is further connected to the evacuation piping.