Vacuum pump system and vacuum pump

Abstract

The present invention relates to a vacuum pump system and a vacuum pump. The object of the present invention is to suppress generation of reaction products inside the vacuum pump and maintain exhaust performance. A vacuum pump system (100) includes a first vacuum pump (1) and a second vacuum pump (3). The second vacuum pump (3) is connected to a first exhaust port (19) of the first vacuum pump (1). The second vacuum pump (3) has a pump portion (5) and a trapping portion (7). The pump portion (5) has a second rotor (51). The trapping portion (7) accumulates reaction products generated from gas introduced into a third internal space (S3) from the first exhaust port (19) by suction of the pump portion (5).

Description

TECHNICAL FIELD

[0001] The present application relates to a vacuum pump system and a vacuum pump. BACKGROUND

[0002] A vacuum pump has a vacuum pump including a turbo vane pump portion and a drag pump portion, wherein the turbo vane pump portion includes a fixed vane and a rotating vane, and the drag pump portion is provided on a more exhaust downstream side than the turbo vane pump portion. A vacuum pump system including the vacuum pump can be used, for example, as a means for making a process chamber in which a process such as dry etching or chemical vapor deposition (CVD) is performed into a high vacuum.

[0003] In a case where the vacuum pump system is used to make a process chamber into a high vacuum, it is possible that a reaction product is generated and deposited in the vacuum pump, other devices (for example, a dry pump) other than the vacuum pump, and / or a gas piping included in the vacuum pump system. Generation of the reaction product in the vacuum pump system needs to be suppressed. The reason is that if the reaction product is deposited inside the vacuum pump, a part (for example, a rotor) of the vacuum pump can come into contact with the reaction product. In addition, the reason is that if the reaction product is deposited in the other devices and the gas piping, the exhaust capability of the vacuum pump system can be reduced.

[0004] As a method of suppressing generation of a reaction product inside a vacuum pump, a method of warming up the inside of the vacuum pump is known. For example, in Patent Literature 1, the inside of the vacuum pump is warmed up by heating the main body of the vacuum pump with a heater. In addition, in Patent Literature 2, a high-temperature purge gas is introduced into the inside of the vacuum pump to warm it up. On the other hand, in order to suppress deposition of a reaction product in a gas piping and a device connected to the exhaust side of the vacuum pump, in Patent Literature 3, a filter is provided on the exhaust side of the vacuum pump.

[0005] [Patent Literature]

[0006] [Patent Literature]

[0007] [Patent Literature 1] Japanese Patent Application Laid-Open (JP A) No. 2020-112133

[0008] [Patent Literature 2] Japanese Patent Application Laid-Open (JP A) No. 2020-90922

[0009] [Patent Literature 3] Japanese Patent Application Laid-Open (JP A) No. 2006-74362 SUMMARY

[0010] [Problem to be Solved by the Invention]

[0011] However, it is preferable to suppress the temperature rise in the interior of the vacuum pump. The reason is that as the temperature of the interior of the vacuum pump rises, the rotor expands and easily comes into contact with other parts. The reason is that as a result, the life of the vacuum pump determined by the time during which the rotor expands and comes into contact with other parts becomes short.

[0012] In addition, in the case where the interior of the vacuum pump is warmed up by the method of Patent Document 1 and Patent Document 2, in order to suppress further temperature rise, it is not possible to increase the exhaust flow rate of the vacuum pump. Specifically, it is necessary to reduce the exhaust flow rate of the vacuum pump, reduce the load applied to the motor that rotates the rotor, and suppress the heat generation from the motor.

[0013] Further, in the case where a filter is provided on the exhaust side of the vacuum pump as in Patent Document 3, as the reaction product accumulates in the filter, the flow of the gas on the exhaust side of the vacuum pump deteriorates. If the flow of the gas on the exhaust side of the vacuum pump deteriorates, the pressure (back pressure) on the exhaust side of the vacuum pump becomes high. As a result, the exhaust performance of the vacuum pump decreases and / or the load of the motor increases and heat generation becomes more.

[0014] An object of the present application is to suppress the generation of a reaction product in the interior of a vacuum pump and maintain the exhaust performance in a vacuum pump system.

[0015] [Technical Means to Solve the Problem]

[0016] A vacuum pump system of an aspect of the present application includes a first vacuum pump and a second vacuum pump. The second vacuum pump is connected to the exhaust port of the first vacuum pump. The second vacuum pump has a pump portion and a trapping portion. The pump portion has a rotor. The trapping portion accumulates a reaction product generated from a gas introduced into an internal space from the exhaust port of the first vacuum pump by suction of the pump portion.

[0017] A vacuum pump of an aspect of the present application includes a pump portion having a rotor and a trapping portion that accumulates a reaction product generated from a gas introduced into an internal space by suction of the pump portion.

[0018] [Effects of the Invention]

[0019] In the vacuum pump system of the aspect of the present application, the pump portion of the second vacuum pump introduces a gas from the exhaust port of the first vacuum pump to the internal space of the trapping portion of the second vacuum pump by suction. Thereby, the pressure of the exhaust path from the interior of the first vacuum pump to the second vacuum pump can be reduced, and thus the generation of a reaction product in the interior of the first vacuum pump and in the exhaust path from the first vacuum pump to the second vacuum pump is suppressed. As a result, the maintenance frequency of the first vacuum pump and the gas piping can be reduced. In addition, since the reaction product accumulates in the internal space of the trapping portion of the second vacuum pump, the generation of a reaction product in the pump portion can be suppressed.

[0020] In addition, by suppressing generation of the reaction product in the exhaust path from the first vacuum pump to the second vacuum pump, the conductance of the exhaust path is maintained in a high state. As a result, the ability of the pump portion to suck the exhaust port of the first vacuum pump does not decrease, and thus the pressure (back pressure) on the exhaust side of the first vacuum pump can be maintained low. Further, in order to suppress generation of the reaction product, there is no need to raise the temperature of the inside of the first vacuum pump. As a result, the exhaust performance of the vacuum pump system can be maintained in a high state. In addition, the exhaust ability of the first vacuum pump is improved. BRIEF DESCRIPTION OF DRAWINGS BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a view showing the structure of a vacuum pump system according to an embodiment.

[0022] Figure 2 is a sectional view of a first vacuum pump.

[0023] Figure 3 is a sectional view of a second vacuum pump.

[0024] Figure 4 is a sectional view of a second vacuum pump in which a trapping portion is provided midway in the pump portion.

[0025] [Explanation of Symbols]

[0026] 100: vacuum pump system

[0027] 1: first vacuum pump

[0028] 11: first suction port

[0029] 13: first rotor

[0030] 13A: rotor blade

[0031] 13B: rotor cylindrical portion

[0032] 15: first stator

[0033] 15A: stator blade

[0034] 15B: stator cylindrical portion

[0035] 17: first motor

[0036] 19: first exhaust port

[0037] 21: first base

[0038] 23: first bearing

[0039] S1: first internal space

[0040] S2: second internal space

[0041] 2: on-off valve

[0042] 3: second vacuum pump

[0043] 5: pump portion

[0044] 51: second rotor

[0045] 51A: shaft

[0046] 51B: second rotor cylindrical portion

[0047] 53: second stator

[0048] 53A: first end

[0049] 53B: second end

[0050] 01: opening

[0051] 55A to 55D: second bearing

[0052] 57: second base

[0053] 59: second motor

[0054] 61: second exhaust port

[0055] 63: first heater

[0056] 7: trapping portion

[0057] 7A: bottom surface portion

[0058] 7B: side surface portion

[0059] S3: third internal space

[0060] 71: second suction port

[0061] 73: cooling portion

[0062] 75: plasma generating portion

[0063] 77: second heater

[0064] 9: third vacuum pump

[0065] CH: exhaust target device

[0066] L1: first gas line

[0067] L2: second gas line

[0068] L3: third gas line

[0069] L4: fourth gas line

[0070] L5: fifth gas line

[0071] V1: first valve

[0072] V2: second valve DETAILED DESCRIPTION

[0073] 1. Structure of vacuum pump system

[0074] Hereinafter, a structure of a vacuum pump system according to an embodiment will be described with reference to the drawings. Figure 1 is a view showing a structure of a vacuum pump system 100 according to the embodiment. The vacuum pump system 100 is a system that exhausts gas inside an exhaust target device CH. The exhaust target device CH is, for example, a process chamber of a semiconductor manufacturing device. The vacuum pump system 100 includes a first vacuum pump 1, a second vacuum pump 3, and a third vacuum pump 9.

[0075] The suction side of the first vacuum pump 1 is connected to the inside of the exhaust target device CH via an on-off valve 2. The on-off valve 2 switches whether the suction side of the first vacuum pump 1 is communicated with or cut off from the inside of the exhaust target device CH by opening and closing of the valve. In addition, the on-off valve 2 is a vacuum valve that controls the pressure of the inside of the exhaust target device CH by controlling the opening degree of the valve. The exhaust side of the first vacuum pump 1 is connected to the second vacuum pump 3 via a first gas line L1.

[0076] The second vacuum pump 3 has a pump portion 5 and a trapping portion 7. The suction side of the pump portion 5 is connected to the trapping portion 7. The trapping portion 7 is connected to the exhaust side of the first vacuum pump 1 via the first gas line L1. The exhaust side of the pump portion 5 is connected to the suction side of the third vacuum pump 9 via a second gas line L2, a first valve V1, and a third gas line L3. The third vacuum pump 9 is, for example, a dry pump. In addition, the suction side of the third vacuum pump 9 is connected to the inside of the exhaust target device CH via a fourth gas line L4, a second valve V2, a fifth gas line L5, and the third gas line L3.

[0077] 2. Structure of first vacuum pump

[0078] Hereinafter, a detailed structure of the first vacuum pump 1 will be described using Figure 2 A detailed structure of the first vacuum pump 1 will be described. Figure 2 is a sectional view of the first vacuum pump 1. The first vacuum pump 1 includes a first suction port 11, a first rotor 13, a first stator 15, a first motor 17, and a first exhaust port 19. The first suction port 11 is located at the suction side of the first vacuum pump 1 and is connected to the inside of the exhaust target device CH via the on-off valve 2.

[0079] The first rotor 13 includes multi-stage rotor blades 13A and a rotor cylinder portion 13B. The first rotor 13 is rotatably supported by a first base 21 and a first bearing 23. The first rotor 13 is rotated by a first motor 17. The first stator 15 includes multi-stage stator blades 15A and a stator cylinder portion 15B. A screw groove is formed in an inner peripheral surface (a surface facing the rotor cylinder portion 13B) of the stator cylinder portion 15B. In the first vacuum pump 1, the rotor blades 13A and the stator blades 15A are alternately arranged, and a turbo-molecular pump portion is configured. On the other hand, the rotor cylinder portion 13B and the stator cylinder portion 15B are arranged facing each other with a slight gap at a lower portion of the turbo-molecular pump portion, and a screw groove pump portion is configured. A first exhaust port 19 communicates with a first internal space S1 of a lower portion of the screw groove pump portion. The first exhaust port 19 is connected to the second vacuum pump 3 via a first gas line L1.

[0080] In the first vacuum pump 1, the first rotor 13 is rotated by the first motor 17, and thus the turbo-molecular pump portion and the screw groove pump portion suck gas in the inside of the exhaust target device CH toward the first suction port 11. The turbo-molecular pump portion and the screw groove pump portion introduce the gas sucked into the first suction port 11 into the first internal space S1 and discharge the gas from the first exhaust port 19. As a result, the inside of the exhaust target device CH becomes a high vacuum state. The gas discharged from the first exhaust port 19 is sucked into the second vacuum pump 3.

[0081] 3. Structure of second vacuum pump

[0082] Next, the structure of the second vacuum pump 3 will be described. Figure 3 The structure of the second vacuum pump 3 will be described. Figure 3 is a cross-sectional view of the second vacuum pump 3. Also, Figure 3 An arrow of the drawing indicates a vertical direction. As described above, the second vacuum pump 3 includes a pump portion 5 and a trapping portion 7. The pump portion 5 includes a second rotor 51 and a second stator 53.

[0083] The second rotor 51 has a shaft 51A. The shaft 51A is rotatably supported by a plurality of second bearings 55A to 55D. The plurality of second bearings 55A to 55D are installed at positions of a second base 57 at which the shaft 51A is accommodated. The second bearing 55A is, for example, a ball bearing. On the other hand, the other second bearings 55B to 55D are, for example, magnetic bearings. Among them, the plurality of second bearings 55B to 55D can be other kinds of bearings such as ball bearings. A second motor 59 is further installed at the positions of the second base 57 at which the shaft 51A is accommodated. The second motor 59 rotates the second rotor 51. A second rotor cylinder portion 51B is formed in an outer peripheral portion of the second rotor 51. The second rotor cylinder portion 51B extends in an axial direction in which the shaft 51A extends.

[0084] The second stator 53, which corresponds to the housing, is a cylindrical member having a first end 53A and a second end 53B. The first end 53A is connected to the second base 57. The second end 53B forms the opening O1. The second stator 53 accommodates the second rotor 51 in a state in which a slight gap is formed between the outer peripheral surface of the second rotor cylindrical portion 51B and the inner peripheral surface of the second stator 53. A screw groove is formed in the inner peripheral surface of the second stator 53, i.e., the surface facing the second rotor cylindrical portion 51B. A slight gap is formed between the outer peripheral surface of the second rotor cylindrical portion 51B and the inner peripheral surface of the second stator 53, and a screw groove is formed in the inner peripheral surface of the second stator 53, whereby the second rotor cylindrical portion 51B and the second stator 53 form a Holweck pump portion. The Holweck pump portion is connected to the second internal space S2. The second internal space S2 is a space surrounded by the upper end portion of the second rotor cylindrical portion 51B, the first end 53A side of the second stator 53, and the second base 57.

[0085] Further, in the Holweck pump portion, a screw groove can be provided in the outer peripheral surface of the second rotor cylindrical portion 51B facing the second stator 53 instead of being provided in the inner peripheral surface of the second stator 53.

[0086] A second exhaust port 61 is provided in the upper portion of the second stator 53. The second exhaust port 61 is connected to the second internal space S2. The second exhaust port 61 is located on the exhaust side of the second vacuum pump 3 and is connected to the intake side of the third vacuum pump 9 via the second gas line L2, the first valve V1, and the third gas line L3.

[0087] A first heater 63 is provided in the outer peripheral surface of the second stator 53. The first heater 63 heats the pump portion 5. By heating the pump portion 5 with the first heater 63, the generation of reaction products in the pump portion 5 can be suppressed. The heating temperature of the pump portion 5 by the first heater 63 is, for example, 150°C. The heating temperature can be appropriately set according to the raw material or the like used in the process performed in the exhaust target device CH.

[0088] In the pump portion 5, the second rotor 51 is rotated by the second motor 59, whereby the Holweck pump portion inhales gas at the opening O1. The Holweck pump portion introduces the inhaled gas into the second internal space S2 and discharges it from the second exhaust port 61. The gas discharged from the second exhaust port 61 is inhaled by the third vacuum pump 9.

[0089] The trapping portion 7 has a bottom surface portion 7A and side surface portions 7B. One end of the side surface portion 7B is connected to the bottom surface portion 7A. The bottom surface portion 7A and the side surface portion 7B form a third internal space S3. The trapping portion 7 has, for example, a cylindrical shape in which the bottom surface portion 7A is circular. The trapping portion 7 has a cylindrical shape, whereby gas can be easily retained in the third internal space S3. Further, the trapping portion 7 can have a shape other than a cylindrical shape (for example, a rectangular parallelepiped, a solid shape in which the bottom surface portion 7A is polygonal, or the like) as long as gas can be retained in the interior for a certain period of time.

[0090] In addition to this, another gas retention structure can be provided in the third internal space S3 of the trapping portion 7. For example, a wall surface can be provided in the third internal space S3 to form a portion in which gas is less likely to flow in the third internal space S3. For example, a gas retention structure such as a louver shape, a spiral shape, or a fin can be provided in the bottom surface portion 7A.

[0091] The other end of the side surface portion 7B is connected to the second end 53B of the second stator 53. Further, the side surface portion 7B can be fixed to the second stator 53 by welding or the like, or can be connected to the second stator 53 by a screw or the like so as to be detachable from the second stator 53. In the case where the side surface portion 7B is connected to the second stator 53 so as to be detachable from the second stator 53, the side surface portion 7B and the second stator 53 are hermetically connected, for example, by a method in which a gas seal or the like is provided between the side surface portion 7B and the second stator 53.

[0092] The side opposite to the bottom surface portion 7A of the third internal space S3 is open and is connected to the opening O1. The second gas suction port 71 is provided in either of the side surface portions 7B. The second gas suction port 71 is connected to the third internal space S3. The second gas suction port 71 is connected to the first gas discharge port 19 of the first vacuum pump 1 via the first gas line L1. Thus, the opening O1 of the pump portion 5 is capable of gas communication with the third internal space S3, the second gas suction port 71, the first gas line L1, and the first gas discharge port 19 of the first vacuum pump. Thus, the pump portion 5 can introduce the gas discharged from the first gas discharge port 19 of the first vacuum pump 1 into the third internal space S3 via the first gas line L1.

[0093] The trapping portion 7 is, for example, a member made of a metal such as aluminum or stainless steel. The trapping portion 7 can be formed, for example, by bending a metal plate, or can be formed by forming the bottom surface portion 7A and the side surface portion 7B as separate members and connecting the bottom surface portion 7A and the side surface portion 7B by welding or the like.

[0094] As Figure 3As shown, the opening O1 of the pump portion 5 is disposed on the lower side in the vertical direction. In addition, the trapping portion 7 is disposed on the lower side in the vertical direction than the opening O1. That is, the trapping portion 7 is disposed on the lower side in the vertical direction than the pump portion 5. Thus, the reaction product accumulated on the bottom surface portion 7A and the side surface portion 7B of the trapping portion 7 stays in the trapping portion 7 due to gravity and is less likely to intrude into the pump portion 5.

[0095] The second vacuum pump 3 includes a cooling portion 73. The cooling portion 73 is installed in a state of being in contact with the bottom surface portion 7A of the trapping portion 7. Further, the cooling portion 73 can also be installed on the side surface portion 7B of the trapping portion 7. The cooling portion 73 is, for example, a pipe made of metal through which a cooling liquid can flow. The cooling portion 73 cools the bottom surface portion 7A and the side surface portion 7B of the trapping portion 7. By cooling the bottom surface portion 7A and the side surface portion 7B, the gas in the third internal space S3 can be cooled. By cooling the gas in the third internal space S3, the generation of the reaction product in the third internal space S3 can be promoted. The reason for this is that, in a case where the reaction product is generated using the gas introduced into the inside of the exhaust target device CH, that is, the gas exhausted by the vacuum pump system 100 as a raw material, the lower the temperature of the gas, the more likely the reaction product is to be generated.

[0096] The second vacuum pump 3 includes a plasma generating portion 75. The plasma generating portion 75 is provided in the third internal space S3 of the trapping portion 7. The plasma generating portion 75 generates plasma in the third internal space S3. The plasma generated from the plasma generating portion 75 decomposes the reaction product accumulated in the third internal space S3 and the like. For example, by generating plasma from the plasma generating portion 75 at the time of maintenance, cleaning (removal of the reaction product) of the trapping portion 7 and the like can be performed. The plasma generating portion 75 is, for example, a parallel-plate type plasma generating device, a device for generating inductively coupled plasma (ICP).

[0097] The second vacuum pump 3 includes a second heater 77. The second heater 77 is provided on the side surface portion 7B of the trapping portion 7. The second heater 77 heats the trapping portion 7. Thus, the reaction product accumulated in the trapping portion 7 can be removed by heating of the trapping portion 7 by the second heater 77. The heating temperature of the trapping portion 7 by the second heater 77 is, for example, 150°C. The heating temperature can be appropriately set according to the raw material and the like used in the process performed in the exhaust target device CH.

[0098] Further, in the second vacuum pump 3, the position at which the trapping portion 7 is provided is not limited to the portion of the opening O1 of the pump portion 5. For example, as shown in FIG. 6, the trapping portion 7 can also be provided in the middle of the pump portion 5. Specifically, the trapping portion 7 can be provided in such a manner that the third internal space S3 is connected to the opening portion provided in the second stator 53. Figure 4 Further, in the second vacuum pump 3, the position at which the trapping portion 7 is provided is not limited to the portion of the opening O1 of the pump portion 5. For example, as shown in FIG. 6, the trapping portion 7 can also be provided in the middle of the pump portion 5. Specifically, the trapping portion 7 can be provided in such a manner that the third internal space S3 is connected to the opening portion provided in the second stator 53. Figure 4Fig. 6 is a sectional view of the second vacuum pump 3 in which the trapping portion 7 is provided midway through the pump portion 5. Further, in the modification, the opening O1 of the pump portion 5 is connected to the first exhaust port 19 of the first vacuum pump 1.

[0099] In the second vacuum pump 3 in which the trapping portion 7 is provided midway through the pump portion 5, the pump portion 5 introduces gas from the first exhaust port 19 of the first vacuum pump 1 to the opening O1. The gas introduced to the opening O1 is exhausted from the second exhaust port 61 by the suction of the pump portion 5, through between the second rotor cylinder portion 51B and the second stator 53. During the period in which the gas introduced to the opening O1 passes through between the second rotor cylinder portion 51B and the second stator 53, the gas is trapped in the third internal space S3 of the trapping portion 7. A reaction product is generated from the gas trapped in the third internal space S3, and is accumulated in the trapping portion 7.

[0100] 4. Vacuuming operation of exhaust target apparatus

[0101] Next, the vacuuming operation of the exhaust target apparatus CH using the vacuum pump system 100 will be described. First, the exhaust target apparatus CH is vacuumed until the pressure reaches a level at which the first vacuum pump 1 can be operated. This vacuuming can be achieved by operating the third vacuum pump 9 with the second valve V2 open, and sucking the interior of the exhaust target apparatus CH by the third vacuum pump 9. In this vacuuming operation, the on-off valve 2 and the first valve V1 are closed.

[0102] After the interior of the exhaust target apparatus CH reaches a pressure at which the first vacuum pump 1 can be operated, vacuuming is started using the first vacuum pump 1. Specifically, after the second valve V2 is closed and the first valve V1 is opened, the first vacuum pump 1 and the second vacuum pump 3 are operated. Then, vacuuming is started using the first vacuum pump 1 by opening the on-off valve 2. Further, in the case where the first vacuum pump 1 and the second vacuum pump 3 are operated all the time, vacuuming is started using the first vacuum pump 1 by closing the second valve V2 and opening the first valve V1, and then opening the on-off valve 2.

[0103] After the exhaust target apparatus CH is brought to a high vacuum state by the first vacuum pump 1, various processes are performed in the interior of the exhaust target apparatus CH. For example, a process of generating a semiconductor material using a gas introduced into the interior of the exhaust target apparatus CH as a raw material is performed. Alternatively, a process of etching a substrate or the like using a gas introduced into the interior of the exhaust target apparatus CH as an etching gas is performed.

[0104] The gas introduced into the inside of the exhaust target device CH is exhausted by the vacuum pump system 100. Specifically, the gas in the inside of the exhaust target device CH is first sucked into the first vacuum pump 1 and exhausted from the first exhaust port 19. The gas exhausted from the first exhaust port 19 is introduced into the third internal space S3 through the first gas line L1 due to suction by the pump portion 5 of the second vacuum pump 3. The gas introduced into the third internal space S3 is cooled during the period of staying in the third internal space S3. As a result, a reaction product is generated from the gas introduced into the third internal space S3, and is accumulated in the trapping portion 7. The gas introduced into the third internal space S3 is exhausted from the second exhaust port 61 through the pump portion 5 after the generation of the reaction product, and is sucked into the third vacuum pump 9.

[0105] In the vacuum pump system 100, the third internal space S3 of the second vacuum pump 3 is connected to the first exhaust port 19 via the first gas line L1. In addition, the first exhaust port 19 is connected to the inside of the first vacuum pump 1. Therefore, the pressure in the inside of the first vacuum pump 1 is lowered by the pump portion 5 of the second vacuum pump 3. If the pressure in the inside of the first vacuum pump 1 becomes low, the partial pressure of the gas in the inside of the first vacuum pump 1 as a raw material of the reaction product becomes lower than the saturated vapor pressure, and thus the generation and accumulation of the reaction product in the inside of the first vacuum pump 1 are suppressed. If the reaction product does not accumulate in the inside, the inside of the first vacuum pump 1 does not need to be cleaned. In addition, since the first exhaust port 19 and the first gas line L1 are also sucked by the pump portion 5, the generation of the reaction product in the first exhaust port 19 and the first gas line L1 is also suppressed. As a result, the maintenance frequency of the first vacuum pump 1 and the first gas line L1 can be reduced.

[0106] In addition, by suppressing the generation of the reaction product in the first exhaust port 19 and the first gas line L1, the conductance of the first exhaust port 19 and the first gas line L1 is maintained in a high state. As a result, the ability of the pump portion 5 to suck the first exhaust port 19 does not decrease, and thus the back pressure of the first vacuum pump 1 can be maintained low. As a result, the vacuum pump system 100 can maintain the ability to exhaust the inside of the exhaust target device CH in a high state. Furthermore, in order to suppress the generation of the reaction product, the inside of the first vacuum pump 1 does not need to be warmed up, and thus the exhaust ability of the first vacuum pump 1 is improved. Specifically, the amount of gas that can be exhausted by the first vacuum pump 1 can be increased. In addition, the inside of the exhaust target device CH can be made to be a higher vacuum than in the past.

[0107] In the vacuum pump system 100, the reaction product is generated and accumulated in the trapping portion 7 of the second vacuum pump 3, and the gas after the generation of the reaction product is exhausted by the pump portion 5. Thus, the reaction product is not easily generated in the pump portion 5. As a result, the cleaning frequency of the pump portion 5 can be reduced, and thus the maintenance of the second vacuum pump 3 becomes easy. In the case where a large amount of the reaction product is accumulated in the trapping portion 7, the trapping portion 7 is replaced or cleaned.

[0108] In addition, in the second vacuum pump 3 in which the trapping portion 7 is provided to the large opening O1 of the second stator 53, even if a large amount of reaction products are deposited in the trapping portion 7, the conductance between the pumping portion 5 and the third internal space S3 does not decrease, and the suction capacity of the pumping portion 5 to the third internal space S3 does not easily decrease.

[0109] Further, in the vacuum pump system 100, not only the first vacuum pump 1 and the second vacuum pump 3 can be operated to evacuate the interior of the exhaust target apparatus CH, but also only the second vacuum pump 3 can be operated to evacuate the interior of the exhaust target apparatus CH. The exhaust capacity of the second vacuum pump 3 is not as high as that of the first vacuum pump 1, and thus by evacuating the interior of the exhaust target apparatus CH using only the second vacuum pump 3, the interior of the exhaust target apparatus CH can be evacuated to a high pressure that cannot be achieved by the first vacuum pump 1. As a result, the types of processes that can be performed using one exhaust target apparatus CH can be increased. For example, a process requiring high vacuum (e.g., sputtering, etching) and a process requiring low vacuum (e.g., CVD) can be performed using one exhaust target apparatus CH. Further, when the interior of the exhaust target apparatus CH is evacuated using only the second vacuum pump 3, reaction products are less likely to be generated in the interior of the first vacuum pump 1, for example, by warming the interior of the first vacuum pump 1.

[0110] 5. Cleaning operation using the plasma generation portion

[0111] Next, a cleaning operation of the vacuum pump system 100 or the like using the plasma generation portion 75 provided in the trapping portion 7 of the second vacuum pump 3 will be described. The cleaning using the plasma generation portion 75 is performed by bringing the on-off valve 2, the first valve VI, and / or the second valve V2 to the open state, and generating plasma in the third internal space S3 using the plasma generation portion 75. As a result, radicals generated by the plasma can remove reaction products from the third internal space S3 to a place where the radicals can reach.

[0112] In addition, the cleaning can also be performed by bringing the on-off valve 2 and the second valve V2 to the open state, and on the other hand, bringing the first valve VI to the closed state, operating the third vacuum pump 9, and generating plasma in the third internal space S3 using the plasma generation portion 75. In this case, radicals generated by the plasma easily reach the first gas line LI, the interior of the first vacuum pump 1, the interior of the exhaust target apparatus CH, the fourth gas line L4, the fifth gas line L5, and the third gas line L3 from the third internal space S3. As a result, cleaning can be performed from the third internal space S3 to the first gas line LI, the interior of the first vacuum pump 1, the interior of the exhaust target apparatus CH, the fourth gas line L4, the fifth gas line L5, and the third gas line L3.

[0113] In addition, cleaning can also be performed by operating the third vacuum pump 9 with the first valve V1 in the open state and the other valves 2 and the second valve V2 in the closed state, and generating plasma in the third internal space S3 using the plasma generation section 75. In this case, radicals generated by the plasma easily reach the second gas line L2 and the third gas line L3 from the third internal space S3. As a result, cleaning from the third internal space S3 to the second gas line L2 and the third gas line L3 can be performed.

[0114] In the vacuum pump system 100 of the above-described embodiment, the pump section 5 of the second vacuum pump 3 sucks in gas from the first exhaust port 19 of the first vacuum pump 1 to the third internal space S3 of the trapping section 7 of the second vacuum pump 3. Thereby, the pressure of the exhaust path from the inside of the first vacuum pump 1 to the second vacuum pump 3 can be reduced. If the pressure of the exhaust path from the inside of the first vacuum pump 1 to the second vacuum pump 3 is low, the partial pressure of the gas of the raw material of the reaction product in these places becomes lower than the saturated vapor pressure, and thus the generation and accumulation of the reaction product in the exhaust path from the inside of the first vacuum pump 1 to the second vacuum pump 3 is suppressed. As a result, the maintenance frequency of the first vacuum pump 1 and the gas piping (the first gas line L1) can be reduced. In addition, the reaction product is accumulated in the third internal space S3 of the trapping section 7 of the second vacuum pump 3, and thus the generation of the reaction product in the pump section 5 can be suppressed.

[0115] In addition, by suppressing the generation of the reaction product in the exhaust path from the first vacuum pump 1 to the second vacuum pump 3, the conductance of the exhaust path is maintained in a high state. As a result, the ability of the pump section 5 to suck the first exhaust port 19 of the first vacuum pump 1 is not reduced, and thus the back pressure on the exhaust side of the first vacuum pump 1 can be maintained low. Furthermore, in order to suppress the generation of the reaction product, the inside of the first vacuum pump 1 does not need to be warmed up. As a result, the exhaust performance of the vacuum pump system 100 can be maintained in a high state. Furthermore, in order to suppress the generation of the reaction product, the inside of the first vacuum pump 1 does not need to be warmed up, and thus the exhaust ability of the first vacuum pump 1 is improved.

[0116] The above describes one embodiment of the present application, but the present application is not limited to the described embodiment, and various modifications can be made without departing from the gist of the application.

[0117] The second vacuum pump 3 can also not be assembled in the vacuum pump system 100 in advance. That is, the second vacuum pump 3 can also be used as a stand-alone vacuum pump. In this case, the second vacuum pump 3 can be assembled into an existing system including the first vacuum pump 1 and the third vacuum pump 9.

[0118] In the second vacuum pump 3, the positional relationship between the pump section 5 and the collecting section 7 is such that the reaction products accumulated in the collecting section 7 are unlikely to enter the pump section 5. The collecting section 7 need not be located vertically below the pump section 5. For example, the pump section 5 and the collecting section 7 may be arranged horizontally.

[0119] The method of causing gas to stagnate in the third internal space S3 of the second vacuum pump 3 is not limited to configuring the third internal space S3 so that gas can easily stagnate. For example, gas can be stagnate in the third internal space S3 by rotating the second rotor 51 of the pump unit 5 at an appropriate rotational speed.

[0120] The first vacuum pump 1 of the embodiment described above is an integrated pump comprising a turbomolecular pump unit and a screw-type pump. The turbomolecular pump unit includes a multi-stage rotor blade 13A and a multi-stage stator blade 15A, while the screw-type pump includes a rotor cylindrical portion 13B and a stator cylindrical portion 15B. However, the screw-type pump can be omitted. In other words, the first vacuum pump 1 can be a turbomolecular pump. Alternatively, the turbomolecular pump can be omitted. In other words, the first vacuum pump 1 can be a screw-type pump.

[0121] Those skilled in the art should understand that the multiple exemplary embodiments described above are specific examples of the following aspects.

[0122] (First aspect) A vacuum pump system includes a first vacuum pump and a second vacuum pump connected to the exhaust port of the first vacuum pump. The second vacuum pump includes a pump unit and a collection unit. The pump unit includes a rotor. Reaction products generated by gas introduced into the internal space from the exhaust port of the first vacuum pump by suction of the pump unit accumulate in the collection unit.

[0123] In the first embodiment of the vacuum pump system, the pump unit of the second vacuum pump draws gas from the exhaust port of the first vacuum pump into the internal space of the second vacuum pump's collection unit. This reduces the pressure in the exhaust path from the interior of the first vacuum pump to the second vacuum pump, thereby suppressing the formation of reaction products within the first vacuum pump and in the exhaust path from the first vacuum pump to the second vacuum pump. Consequently, the maintenance frequency of the first vacuum pump and gas piping can be reduced. Furthermore, since reaction products accumulate in the internal space of the second vacuum pump's collection unit, the formation of reaction products in the pump unit can be suppressed.

[0124] Furthermore, by suppressing the formation of reaction products in the exhaust path from the first vacuum pump to the second vacuum pump, the conductance of the exhaust path is maintained at a high level. As a result, the pump unit's ability to draw air into the exhaust port of the first vacuum pump is not reduced, thereby maintaining low back pressure on the exhaust side of the first vacuum pump. Furthermore, there is no need to increase the internal temperature of the first vacuum pump. As a result, the exhaust performance of the vacuum pump system can be maintained at a high level. Furthermore, the exhaust capacity of the first vacuum pump is improved.

[0125] The vacuum pump system of the second aspect can further include a cooling section. The cooling section cools the trapping section. Thereby, the gas in the internal space of the trapping section 7 can be cooled, and the reaction product is easily generated in the internal space.

[0126] The vacuum pump system of the third aspect can further include a cooling section. The cooling section cools the trapping section. Thereby, the gas in the internal space of the trapping section 7 can be cooled, and the reaction product is easily generated in the internal space.

[0127] The vacuum pump system of the fourth aspect can further include a plasma generating section. The plasma generating section generates plasma in the internal space of the trapping section. Thereby, the cleaning of the reaction product generated in the vacuum pump system can be performed without disassembling the vacuum pump system or the like.

[0128] The vacuum pump system of the fifth aspect can further include a first heater. The first heater heats the pump section. By heating the pump section with the first heater, the reaction product is inhibited from accumulating in the pump section.

[0129] The vacuum pump system of the sixth aspect can further include a second heater. The second heater heats the trapping section. Thereby, the reaction product accumulated in the trapping section can be removed by heating the trapping section with the second heater.

[0130] The vacuum pump of the seventh aspect includes a pump section and a trapping section. The pump section includes a rotor and a stator that houses the rotor. The trapping section has an internal space that is connected to an opening of the stator. The reaction product generated from the gas introduced into the internal space by suction of the pump section is accumulated in the trapping section. In the vacuum pump of the seventh aspect, the reaction product is accumulated in the internal space of the trapping section, and the gas after the generation of the reaction product is exhausted by the pump section. Thereby, the reaction product is not easily generated in the pump section. As a result, the cleaning frequency of the pump section can be reduced, and thus the maintenance of the second vacuum pump becomes easy. In addition, the trapping section is provided at the large opening of the stator, and thus even if a large amount of reaction product is accumulated in the trapping section, the electrical conductance between the pump section and the internal space is not reduced, and the suction ability of the pump section to the internal space is not easily reduced.

Claims

1. A vacuum pump system, characterized in that: include: First vacuum pump; as well as A second vacuum pump is connected to the exhaust port of the first vacuum pump, The second vacuum pump comprises: A Holweg pump unit includes a rotor and a stator, wherein a screw groove is formed in either the rotor or the stator; as well as a collecting portion in which a reaction product generated by the gas introduced into the internal space from the exhaust port by the suction of the Holweg pump portion accumulates; The collecting portion is arranged vertically below the Holvik pump portion. The Holvik pump unit has: a second exhaust port disposed on the upper side in the vertical direction of the stator of the Holweg pump unit; and The opening is arranged on the vertically lower side of the Holweg pump unit and is connected to the internal space of the collection unit.

2. The vacuum pump system according to claim 1, wherein: A cooling unit for cooling the collecting unit is further included.

3. The vacuum pump system according to claim 1 or 2, wherein: The device further includes a plasma generating portion for generating plasma in the internal space.

4. The vacuum pump system according to claim 1 or 2, wherein: A first heater for heating the Holweg pump unit is also included.

5. The vacuum pump system according to claim 1 or 2, wherein: A second heater for heating the collecting portion is further included.

6. A vacuum pump, characterized in that: include: A Holweg pump unit includes a rotor and a stator, wherein a screw groove is formed in either the rotor or the stator; as well as a collecting portion in which a reaction product generated by the gas introduced into the internal space by the suction of the Holvik pump portion accumulates; The collecting portion is arranged vertically below the Holvik pump portion. The Holvik pump unit has: an exhaust port disposed on the upper side in the vertical direction of the stator of the Holweg pump unit; and The opening is arranged on the vertically lower side of the Holweg pump unit and is connected to the internal space of the collection unit.

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