Vacuum exhaust method and vacuum exhaust system

Abstract

Provided is a vacuum exhaust method and a vacuum exhaust system capable of suppressing generation of by-products and solving problems accompanying introduction of a non-active gas. The vacuum exhaust method includes: a rising process of rising a rotational speed of a vacuum pump device (DP) to a prescribed stable speed after starting the vacuum pump device (DP); and a gas introduction process of introducing a non-active gas to the vacuum pump device (DP) after the rotational speed of the vacuum pump device (DP) reaches the stable speed.

Description

TECHNICAL FIELD

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

[0002] In order to maintain a vacuum chamber of a semiconductor manufacturing apparatus (for example, an etching apparatus, a chemical vapor deposition (CVD) apparatus, or the like) in a vacuum state, a vacuum pump apparatus that exhausts gas in the vacuum chamber is known.

[0003] A gas for film formation (processing gas) supplied into the vacuum chamber can include a gas that generates a by-product. In this case, when the vacuum pump apparatus exhausts the gas in the vacuum chamber, there is a concern that the by-product flows into the vacuum pump apparatus together with the gas, or the by-product is generated in the vacuum pump apparatus.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Laid-Open (JP A) No. 10-252651

[0007] Patent Document 2: Japanese Patent Application Laid-Open (JP A) No. 2004-293466

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] A by-product is generated depending on temperature and pressure. For example, a by-product is easily generated at high pressure (and / or at low temperature). Therefore, as a means for suppressing generation of a by-product, a method of reducing the pressure of a gas supplied into a vacuum pump apparatus can be considered. An example of this method is a method of introducing a non-reactive gas for diluting the concentration of a gas into the vacuum pump apparatus.

[0010] However, in such a method, more gas is introduced into the vacuum pump apparatus. Therefore, the consumed power for driving the vacuum pump apparatus becomes large, and thus the rotation speed of the vacuum pump apparatus can stagnate before reaching a rated rotation speed (rated rotation speed). As a result, problems such as a very long time being required for starting the vacuum pump apparatus, or the rotation speed of the vacuum pump apparatus not being able to reach the rated rotation speed can occur. SUMMARY

[0011] Therefore, an object of the present application is to provide a vacuum exhaust method and a vacuum exhaust system that can suppress generation of a by-product and solve problems accompanying introduction of a non-reactive gas.

[0012] MEANS OF SOLVING THE PROBLEMS

[0013] In one embodiment, a vacuum exhaust method of exhausting a vacuum chamber by a vacuum pump device is provided. The vacuum exhaust method includes a rising process of rising a rotation speed of the vacuum pump device to a prescribed stable speed after starting the vacuum pump device, and a gas introduction process of introducing a non-active gas to the vacuum pump device after the rotation speed of the vacuum pump device reaches the stable speed.

[0014] In one embodiment, the stable speed includes a first stable speed that is a speed at which an inverter output in a current rotation speed of the vacuum pump device becomes greater than a shaft output of the vacuum pump device, and the gas introduction process is performed after the rotation speed of the vacuum pump device reaches the first stable speed.

[0015] In one embodiment, the stable speed includes a second stable speed that is a speed at which the rotation speed of the vacuum pump device is a rated rotation speed, and the gas introduction process is performed after the rotation speed of the vacuum pump device reaches the second stable speed.

[0016] In one embodiment, the vacuum exhaust method includes a gas heating process of heating the non-active gas by a non-active gas supply line connected to the vacuum pump device.

[0017] In one embodiment, the vacuum exhaust method includes an opening operation process of opening an on-off valve installed to a non-active gas supply line connected to the vacuum pump device in the gas introduction process.

[0018] In one embodiment, the vacuum exhaust method includes a first introduction process of introducing a non-active gas of a first flow rate including zero flow rate to the vacuum pump device through a bypass line branched from a non-active gas supply line connected to the vacuum pump device, and a second introduction process of introducing a non-active gas of a second flow rate greater than the first flow rate to the vacuum pump device.

[0019] In one embodiment, a vacuum exhaust system is provided, including a vacuum pump device that exhausts a vacuum chamber, a gas introduction device that introduces a non-active gas to the vacuum pump device, and a control device that controls an operation of the vacuum pump device and an operation of the gas introduction device. The control device rises a rotation speed of the vacuum pump device to a prescribed stable speed after starting the vacuum pump device, and controls the gas introduction device to introduce the non-active gas to the vacuum pump device after the rotation speed of the vacuum pump device reaches the stable speed.

[0020] In one embodiment, the stable speed includes a first stable speed that is a speed at which the inverter output becomes greater than the shaft output of the vacuum pump device when the rotational speed of the vacuum pump device is currently increasing, and after the rotational speed of the vacuum pump device reaches the first stable speed, the control device controls the gas introduction device to introduce the non-active gas to the vacuum pump device.

[0021] In one embodiment, the stable speed includes a second stable speed that is a speed at which the rotational speed of the vacuum pump device is a rated rotational speed, and after the rotational speed of the vacuum pump device reaches the second stable speed, the control device controls the gas introduction device to introduce the non-active gas to the vacuum pump device.

[0022] In one embodiment, the gas introduction device includes a non-active gas supply line that is connected to the vacuum pump device, and a gas heating structure that heats the non-active gas via the non-active gas supply line.

[0023] In one embodiment, the gas heating structure is a heater that heats the non-active gas supply line.

[0024] In one embodiment, the gas heating structure is a pump housing that is heated by compression heat on the exhaust port side of the vacuum pump device.

[0025] In one embodiment, the gas introduction device includes an on-off valve that opens and closes the non-active gas supply line, and the control device controls the opening and closing operation of the on-off valve.

[0026] In one embodiment, the gas introduction device includes a flow sensor that detects the flow rate of the non-active gas flowing in the non-active gas supply line, and the control device judges the state of the on-off valve based on a flow rate signal transmitted from the flow sensor.

[0027] In one embodiment, the gas introduction device includes a combination of an on-off valve that opens and closes the non-active gas supply line, and a flow sensor that detects the flow rate of the non-active gas flowing in the non-active gas supply line.

[0028] In one embodiment, the gas introduction device includes a bypass line branched from the inactive gas supply line and connected to the vacuum pump device, and a flow control device that controls the flow rate of the inactive gas introduced into the vacuum pump device through the bypass line. The control device performs a first introduction process in which the flow control device introduces inactive gas at a first flow rate including zero flow rate into the vacuum pump device, and after the first introduction process is performed and the rotational speed of the vacuum pump device reaches the stable speed, the control device performs a second introduction process in which the flow control device introduces inactive gas at a second flow rate greater than the first flow rate into the vacuum pump device.

[0029] In one embodiment, the flow control device includes an on-off valve that opens and closes the bypass line.

[0030] In one embodiment, the flow control device includes a flow adjustment valve or a throttle hole installed in the bypass line.

[0031] Effects of the Invention

[0032] The vacuum exhaust method is a method of introducing inactive gas into the vacuum pump device after the rotational speed of the vacuum pump device reaches the stable speed. Therefore, the vacuum exhaust method not only suppresses the generation of by-products, but also shortens the time required for starting the vacuum pump device. Moreover, the problem that the rotational speed of the vacuum pump device cannot reach the rated speed does not occur. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a view showing one embodiment of a vacuum exhaust system.

[0034] Figure 2 is a view showing the operation flow of the control device.

[0035] Figure 3 is a view showing the timing at which the on-off valve is operated to open and close.

[0036] Figure 4 is a view for explaining the first stable speed.

[0037] Figure 5 is a view showing another embodiment of the gas introduction device.

[0038] Figure 6 is a view showing another embodiment of the gas introduction device.

[0039] Figure 7 is a view showing another embodiment of the gas introduction device.

[0040] Figure 8FIG. 2 is a view showing another embodiment of the gas introduction device.

[0041] Figure 9 FIG. 3 is a view showing another embodiment of the gas introduction device.

[0042] Figure 10 FIG. 4 is a view showing another embodiment of the gas introduction device.

[0043] Figure 11 FIG. 5 is a view showing another embodiment of the gas heating structure.

[0044] Symbol explanation

[0045] DS vacuum exhaust system

[0046] CH vacuum chamber

[0047] DP vacuum pump device

[0048] BP booster pump device

[0049] BP1 booster pump

[0050] BP2 motor

[0051] INV1 inverter

[0052] MP main pump device

[0053] MP1 main pump

[0054] MP2 motor

[0055] INV2 inverter

[0056] IP suction port

[0057] EP exhaust port

[0058] RT1 rotor

[0059] RT2 rotor

[0060] GI gas introduction device

[0061] CT control device

[0062] SL inactive gas supply line

[0063] IS gas supply source

[0064] VL1 on-off valve

[0065] VL2 on-off valve

[0066] TVL three-way valve

[0067] OR orifice

[0068] BL bypass line

[0069] FS flow sensor

[0070] FC mass flow sensor

[0071] HT heater

[0072] PC pump housing DETAILED DESCRIPTION

[0073] Embodiments of the present application will be described below with reference to the accompanying drawings.

[0074] Figure 1 is a view showing an embodiment of a vacuum exhaust system. As shown in Figure 1 , the vacuum exhaust system DS is provided with a vacuum pump device DP that exhausts a vacuum chamber CH for performing a process such as etching, film formation, etc. in a semiconductor manufacturing process, a gas introduction device GI that introduces a non-active gas (for example, N2 gas) to the vacuum pump device DP, and a control device CT that controls the operation of the vacuum pump device DP and the operation of the gas introduction device GI.

[0075] The vacuum chamber CH constitutes a part of a semiconductor manufacturing device (not shown) and a process gas that generates a by-product gas is introduced into the vacuum chamber CH. The vacuum pump device DP is connected to the vacuum chamber CH. The vacuum pump device DP exhausts the vacuum chamber CH by driving thereof. The process gas is sucked into the vacuum pump device DP by the exhaust of the vacuum chamber CH.

[0076] In the embodiment shown in Figure 1 , the vacuum pump device DP is provided with two vacuum pump devices (i.e., a booster pump device BP and a main pump device MP). The booster pump device BP is provided with a booster pump BP1, a motor BP2 that drives the booster pump BP1, and an inverter INV1 that is a variable speed member of the motor BP2. Similarly, the main pump device MP is provided with a main pump MP1, a motor MP2 that drives the main pump MP1, and an inverter INV2 that is a variable speed member of the motor MP2. In one embodiment, the vacuum pump device DP can be provided with a separate pump device, or can be provided with three or more vacuum pump devices.

[0077] The gas introduction device GI is connected to the vacuum pump device DP. In Figure 1In the illustrated embodiment, the gas introduction device GI has a non-active gas supply line SL connected to the main pump MP1 of the main pump device MP, a gas supply source IS that supplies the non-active gas to the main pump device MP via the non-active gas supply line SL, and an on-off valve VL1 that opens and closes the non-active gas supply line SL. In one embodiment, the non-active gas supply line SL can also be connected to the booster pump BP1 of the booster pump device BP. In other embodiments, the non-active gas supply line SL can also be connected to both the booster pump BP1 and the main pump MP1.

[0078] The control device CT is electrically connected to the on-off valve VL1 and controls the opening and closing operation of the on-off valve VL1. As an example of the on-off valve VL1, an electromagnetic valve can be cited. When the control device CT closes the on-off valve VL1, the on-off valve VL1 cuts off the supply of the non-active gas from the gas supply source IS to the main pump MP1. When the control device CT opens the on-off valve VL1, the on-off valve VL1 allows the supply of the non-active gas from the gas supply source IS to the main pump MP1.

[0079] The control device CT is electrically connected to the inverter INV1 and the inverter INV2, respectively, and controls the driving operation of the motor BP2 and the motor MP2. In other words, the control device CT controls the operation of the booster pump device BP and the main pump device MP through the motor BP2 and the motor MP2. Hereinafter, in the present specification, the booster pump device BP and the main pump device MP will be collectively referred to as a vacuum pump device DP.

[0080] When the vacuum chamber CH is exhausted, a processing gas containing a gas in which a by-product is generated is sucked into the vacuum pump device DP. As described above, the by-product is generated depending on the pressure (and temperature). Therefore, in order to suppress the generation of the by-product, the gas introduction device GI introduces the non-active gas into the vacuum pump device DP, thereby reducing the pressure of the processing gas.

[0081] However, when the non-active gas is introduced from the start of the vacuum pump device DP, the consumed power of the vacuum pump device DP can become large, and thus the rotation speed of the vacuum pump device DP can not rise but stagnate. As a result, the start of the vacuum pump device DP can take a very long time, and the rotation speed of the vacuum pump device DP can be difficult to reach the rated rotation speed.

[0082] Therefore, in the present embodiment, the control device CT causes the rotation speed of the vacuum pump device DP to rise to a predetermined stable speed after starting the vacuum pump device DP, and after the rotation speed of the vacuum pump device DP reaches the stable speed, controls the gas introduction device GI to introduce the non-active gas to the vacuum pump device DP.

[0083] The control device CT does not introduce the inactive gas during a period from the start of the vacuum pump device DP to the time when the rotation speed of the vacuum pump device DP reaches a stable speed, and introduces the inactive gas to the vacuum pump device DP after the rotation speed of the vacuum pump device DP reaches the stable speed. By such an operation, the control device CT can make the vacuum pump device DP not consume unnecessary electric power at the time of the start, and make the rotation speed of the vacuum pump device DP smoothly reach the rated rotation speed. As a result, the vacuum exhaust system DS can shorten the start-up time of the vacuum pump device DP. Further, by such an operation, the vacuum exhaust system DS can achieve reduction of the usage amount of the inactive gas.

[0084] Figure 2 is a diagram showing the operation flow of the control device. As shown in Figure 2 Step S101, first, the control device CT starts the vacuum pump device DP. Thereafter, as shown in step S102, the rotation speed of the vacuum pump device DP is increased to a prescribed stable speed. This process of increasing the rotation speed is called an increase process. The control device CT judges the rotation speed of the vacuum pump device DP on the basis of the electric power (i.e., current, voltage) supplied to the vacuum pump device DP.

[0085] Figure 3 is a diagram showing the timing of the opening and closing operation of the opening and closing valve. As shown in Figure 3 The prescribed stable speed includes a first stable speed and a second stable speed which is greater than the first stable speed. The first stable speed is the speed at which the inverter output (electric power) in the current rotation speed of the vacuum pump device DP becomes greater than the shaft output of the vacuum pump device DP. The second stable speed is the speed at which the rotation speed of the vacuum pump device DP is the rated rotation speed.

[0086] Figure 4 is a diagram for explaining the first stable speed. As shown in Figure 4 The volume between the suction port IP and the rotor RT1 of the first stage is defined as a first stage volume V1, and the volume between the exhaust port EP and the rotor RT2 of the second stage is defined as a second stage volume V2. The shaft output is the output obtained by adding the compression power (Wc) generated at the time of rotation of the rotor and the mechanical loss (F). The compression power (Wc) can be expressed by the following mathematical expression. Compression power (Wc) = Σ (volume Vi of each stage x rotation speed r x pressure difference Pi of each stage)

[0087] For example, in the embodiment shown in Figure 4 The compression power (Wc) can be expressed by the following mathematical expression. Compression power (Wc) = first stage volume V1 x rotation speed r x (P1 out - P1 in ) + V2 x r x (P2 out - P2 in )

[0088] The mechanical loss (F) is mainly generated due to friction of components of the vacuum pump device DP (e.g., a timing gear, a bearing), and the mechanical loss (F) increases in proportion to the rotational speed of the vacuum pump device DP.

[0089] As shown in step S103, the control device CT judges whether or not the rotational speed of the vacuum pump device DP reaches a prescribed stable speed (a first stable speed or a second stable speed) after the execution of step S102. In a case where the rotational speed of the vacuum pump device DP does not reach the prescribed stable speed (refer to "No" of step S103), the control device CT continues step S102. At this time, the control device CT continues the closing operation of the on-off valve VL1. Figure 2

[0090] In a case where the rotational speed of the vacuum pump device DP reaches the prescribed stable speed (refer to "Yes" of step S103), as shown in step S104, the control device CT opens the on-off valve VL1 of the gas introduction device GI, and introduces the non-active gas to the vacuum pump device DP. This process of introducing the non-active gas is referred to as a gas introduction process.

[0091] In the embodiment shown in Figure 3 , after the rotational speed of the vacuum pump device DP reaches the first stable speed, the control device CT opens the on-off valve VL1 of the gas introduction device GI, and introduces the non-active gas to the vacuum pump device DP. In one embodiment, the first stable speed is decided as a rotational speed (about 60% of the second stable speed (i.e., the rated rotational speed)) at which the performance of the exhaust side of the vacuum pump device DP is sufficiently ensured, and rotational speed stagnation does not occur.

[0092] In one embodiment, the control device CT can open the on-off valve VL1 of the gas introduction device GI, and introduce the non-active gas to the vacuum pump device DP after the rotational speed of the vacuum pump device DP reaches the second stable speed (i.e., the rated rotational speed).

[0093] Figure 5 is a view showing another embodiment of the gas introduction device. As shown in Figure 5 , the gas introduction device GI is branched from the non-active gas supply line SL, and has a bypass line BL connected to the vacuum pump device DP and a flow control device that controls the flow of the non-active gas introduced to the vacuum pump device DP through the bypass line BL.

[0094] In the embodiment shown in Figure 5 ​In the illustrated embodiment, the flow control device is provided with an on-off valve VL2 that opens and closes the bypass line BL. The control device CT is electrically connected to the on-off valve VL2, and controls the opening and closing operation of the on-off valve VL2. The on-off valve VL2 can have the same structure as the on-off valve VL1. As an example of the on-off valve VL2, a solenoid valve can be cited.

[0095] The bypass line BL has a smaller cross-sectional area than the non-active gas supply line SL. With this structure, the flow rate of the non-active gas through the bypass line BL (first flow rate) is smaller than the flow rate of the non-active gas through the non-active gas supply line SL (second flow rate). The first flow rate can also include zero flow rate in which the non-active gas is cut off from passing through the bypass line BL. Therefore, when the on-off valve VL2 is in the closed state, the flow rate of the non-active gas through the bypass line BL is zero. When the on-off valve VL2 is in the open state, the flow rate of the non-active gas through the bypass line BL is greater than zero and smaller than the second flow rate.

[0096] In Figure 5 In the illustrated embodiment, the control device CT can also perform a first introduction process of introducing the non-active gas at the first flow rate through the bypass line BL into the vacuum pump device DP in the above-described rising process. In one embodiment, the first introduction process can be started immediately after the vacuum pump device DP is started. In the first introduction process, the on-off valve VL1 is maintained in the closed state.

[0097] The control device CT can also perform a second introduction process of introducing the non-active gas at a second flow rate greater than the first flow rate into the vacuum pump device DP in the above-described gas introduction process after the first introduction process. In the second introduction process, the control device CT switches the on-off valve VL1 from the closed state to the open state. At this time, the control device CT can close the on-off valve VL2, or can open the on-off valve VL2. By opening the on-off valve VL2, a larger flow rate of the non-active gas can be introduced into the vacuum pump device DP.

[0098] Figure 6 is a view that shows another embodiment of the gas introduction device. As Figure 6 shown, the gas introduction device GI can be provided with a three-way valve TVL as a flow control device instead of the on-off valve VL1 and the on-off valve VL2. In Figure 6 the illustrated embodiment, the three-way valve TVL corresponds to the on-off valve VL1 and the on-off valve VL2.

[0099] As Figure 6As shown, the control device CT is electrically connected to the three-way valve TVL and controls the switching action of the three-way valve TVL. More specifically, the control device CT actuates the three-way valve TVL (i.e., the first actuation) to connect the upstream and downstream sides of the inert gas supply line SL. In this case, the gas supply source IS and the vacuum pump device DP are connected through the inert gas supply line SL. The control device CT actuates the three-way valve TVL (i.e., the second actuation) to connect the upstream side of the inert gas supply line SL and the bypass line BL. In this case, the gas supply source IS and the vacuum pump device DP are connected through the bypass line BL.

[0100] Figure 6 The vacuum exhaust system DS in the illustrated embodiment can also serve the same purpose as... Figure 5 The vacuum exhaust system DS in the illustrated embodiment has the same effect. Therefore, the control device CT causes the three-way valve TVL to perform a second action in the above-mentioned rising process, thereby reducing the first flow rate (in Figure 6 In the illustrated embodiment, the inert gas (zero flow rate) is introduced into the vacuum pump device DP via the bypass line BL. During the gas introduction process, the control device CT activates the three-way valve TVL to perform a first actuation, introducing the inert gas at a second flow rate into the vacuum pump device DP via the inert gas supply line SL.

[0101] Figure 7 This diagram illustrates another embodiment of the gas introduction device. (As shown) Figure 7 As shown, the flow control device can also have a throttling orifice OR installed on the bypass line BL. Figure 7 In the embodiment shown, the control device CT closes the on / off valve VL1 during the aforementioned rising process, while redirecting the first flow rate (in... Figure 7 In the illustrated embodiment, an inert gas with a flow rate greater than zero is introduced into the vacuum pump device DP via a bypass line BL. During the gas introduction process, the control device CT opens the on / off valve VL1, introducing a second flow rate of inert gas into the vacuum pump device DP via the inert gas supply line SL. At this time, the first flow rate of inert gas is introduced into the vacuum pump device DP via the bypass line BL.

[0102] Although not illustrated, the flow control device can also include a flow regulating valve to replace the orifice OR. Furthermore, it can be configured as needed. Figure 5 The implementation methods shown Figure 6 The embodiments shown and Figure 7 The illustrated embodiments can be combined appropriately. For example, a flow control device may also be included. Figure 5 The on / off valve VL2 shown Figure 6 The three-way valve TVL shown and Figure 7 The shown is a throttle orifice OR (or flow control valve).

[0103] Figure 8 is a view showing another embodiment of the gas introduction device. As shown in Figure 8 , the gas introduction device GI can also be provided with a flow rate sensor FS that detects the flow rate of the non-active gas flowing in the non-active gas supply line SL. The flow rate sensor FS is disposed on the downstream side of the open / close valve VL1 in the flow direction of the non-active gas.

[0104] The control device CT is electrically connected to the flow rate sensor FS and determines the flow rate of the non-active gas passing through the flow rate sensor FS based on the flow rate signal transmitted from the flow rate sensor FS. In the embodiment shown in Figure 8 , the control device CT can judge the state (more specifically, abnormality) of the open / close valve VL1 based on the flow rate signal transmitted from the flow rate sensor FS. For example, in the above rising process, in the case where the flow rate of the non-active gas passing through the flow rate sensor FS is greater than a prescribed threshold value (first threshold value), the control device CT can decide that the open / close valve VL1 is abnormal. Likewise, in the above gas introduction process, in the case where the flow rate of the non-active gas passing through the flow rate sensor FS is less than a prescribed threshold value (second threshold value), the control device CT can decide that the open / close valve VL1 is abnormal.

[0105] As such, the control device CT can decide the abnormality of the open / close valve VL1 based on the flow rate signal transmitted from the flow rate sensor FS. The control device CT can transmit an alarm in the case where it is decided that the open / close valve VL1 is abnormal. Although not shown, the flow rate sensor FS can also be installed in the bypass line BL (refer to Figure 5 , Figure 6 and Figure 7 ).

[0106] Figure 9 is a view showing another embodiment of the gas introduction device. As shown in Figure 9 , the gas introduction device GI can also be provided with a mass flow sensor FC. The mass flow sensor FC is a combination of the open / close valve VL1 and the flow rate sensor FS. In the embodiment shown in Figure 9 , the mass flow sensor FC has a structure in which the open / close valve is built in the flow rate sensor. The control device CT is electrically connected to the mass flow sensor FC. The control device CT can cause the mass flow sensor FC to act, control the open / close action of the non-active gas supply line SL, and determine the flow rate of the non-active gas passing through the mass flow sensor FC based on the flow rate signal transmitted from the mass flow sensor FC.

[0107] Figure 10 is a view showing another embodiment of the gas introduction device. In Figure 10In the illustrated embodiment, the gas introduction device GI can also have a gas heating structure that heats the non-active gas by the non-active gas supply line SL. As described above, the by-product is generated depending on not only the pressure but also the temperature. Therefore, in order to suppress the generation of the by-product, the gas introduction device GI can also have the gas heating structure. When the non-active gas heated by the gas heating structure is supplied to the vacuum pump device DP, the temperature of the processing gas is suppressed from decreasing. In other words, the temperature of the processing gas is increased. As a result, the generation of the by-product is suppressed.

[0108] As Figure 10 illustrated, the gas heating structure is a heater HT that heats the non-active gas supply line SL. The heater HT heats the non-active gas supply line SL, and thus the non-active gas that passes through the heated non-active gas supply line SL becomes high temperature. As a result, the non-active gas of high temperature is supplied to the vacuum pump device DP, and thus the generation of the by-product is suppressed. The process of heating the non-active gas is referred to as a gas heating process.

[0109] Figure 11 is a view that illustrates another embodiment of the gas heating structure. As Figure 11 illustrated, the gas heating structure is a pump housing PC that is heated by the compression heat of the exhaust port EP side of the vacuum pump device DP (in the embodiment illustrated in Figure 11 , the main pump device MP). When the gas is compressed and discharged by the driving of the vacuum pump device DP, the pump housing PC (particularly, the exhaust port EP side) is heated and becomes high temperature. Therefore, the non-active gas supply line SL is arranged in contact with the pump housing PC.

[0110] In Figure 11 the illustrated embodiment, the non-active gas supply line SL is wound around the pump housing PC. By such an arrangement, the non-active gas supply line SL is heated by the heat of the pump housing PC, and thus the non-active gas that passes through the heated non-active gas supply line SL becomes high temperature. As a result, the non-active gas of high temperature is supplied to the vacuum pump device DP, and thus the generation of the by-product is suppressed.

[0111] Figure 10 The embodiment illustrated in Figure 11 may also be combined with the embodiment illustrated in. In this case, the gas heating structure has the heater HT that is attached to the non-active gas supply line SL and the structure in which the non-active gas supply line SL is wound around the pump housing PC.

[0112] The above-described embodiments are described for the purpose of enabling a person having ordinary knowledge in the technical field of the present application to carry out the present application. Various modifications of the above-described embodiments can be made by those skilled in the art, and the technical idea of the present application can be applied to other embodiments. Therefore, the present application is not limited to the described embodiments, but should be construed in the broadest scope defined by the technical idea of the patent claims.

Claims

1. A vacuum exhaust method of exhausting a vacuum chamber by a vacuum pump device, characterized by comprising: a rising process of rising a rotation speed of the vacuum pump device to a prescribed stable speed after starting the vacuum pump device; and a gas introduction process of introducing a non-active gas to the vacuum pump device after the rotation speed of the vacuum pump device reaches the stable speed, the vacuum exhaust method comprising: a first introduction process of introducing a first flow rate of the non-active gas including zero flow rate to the vacuum pump device through a bypass line branched from a non-active gas supply line connected to the vacuum pump device; and a second introduction process of introducing a second flow rate of the non-active gas larger than the first flow rate to the vacuum pump device.

2. The vacuum exhaust method according to claim 1, characterized in that the stable speed includes a first stable speed which is a speed at which an inverter output in a current rotation speed of the vacuum pump device becomes larger than a shaft output of the vacuum pump device, the gas introduction process is executed after the rotation speed of the vacuum pump device reaches the first stable speed.

3. The vacuum exhaust method according to claim 1, characterized in that the stable speed includes a second stable speed which is a speed at which the rotation speed of the vacuum pump device is a rated rotation speed, the gas introduction process is executed after the rotation speed of the vacuum pump device reaches the second stable speed.

4. The vacuum exhaust method according to any one of claims 1 to 3, characterized in that the vacuum exhaust method comprises a gas heating process of heating the non-active gas through a non-active gas supply line connected to the vacuum pump device.

5. The vacuum exhaust method according to any one of claims 1 to 3, characterized in that the vacuum exhaust method comprises an open operation process of opening an on-off valve installed to a non-active gas supply line connected to the vacuum pump device in the gas introduction process.

6. A vacuum exhaust system comprising: a vacuum pump device of exhausting a vacuum chamber; a gas introduction device of introducing a non-active gas to the vacuum pump device; and a control device of controlling an operation of the vacuum pump device and an operation of the gas introduction device, the control device rising a rotation speed of the vacuum pump device to a prescribed stable speed after starting the vacuum pump device, the control device controlling the gas introduction device to introduce the non-active gas to the vacuum pump device after the rotation speed of the vacuum pump device reaches the stable speed, the gas introduction device comprising: a bypass line branched from a non-active gas supply line and connected to the vacuum pump device; and a flow rate control device of controlling a flow rate of the non-active gas introduced to the vacuum pump device through the bypass line, the control device executing a first introduction process of introducing a first flow rate of the non-active gas including zero flow rate to the vacuum pump device through the flow rate control device, the control device executing a second introduction process of introducing a second flow rate of the non-active gas larger than the first flow rate to the vacuum pump device through the flow rate control device. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6. A vacuum exhaust system characterized by, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The control device executes a second introduction process for introducing non-active gas at a second flow rate greater than the first flow rate into the vacuum pump device after the first introduction process is executed and the rotational speed of the vacuum pump device reaches the stable speed.

7. The vacuum exhaust system according to claim 6, wherein The stable speed includes a first stable speed that is a speed at which an inverter output in the current rotational speed of the vacuum pump device becomes greater than a shaft output of the vacuum pump device, The control device controls the gas introduction device to introduce the non-active gas into the vacuum pump device after the rotational speed of the vacuum pump device reaches the first stable speed.

8. The vacuum exhaust system according to claim 6, wherein The stable speed includes a second stable speed that is a speed at which the rotational speed of the vacuum pump device is a rated rotational speed, The control device controls the gas introduction device to introduce the non-active gas into the vacuum pump device after the rotational speed of the vacuum pump device reaches the second stable speed.

9. The vacuum exhaust system according to any one of claims 6 to 8, wherein The gas introduction device includes: a non-active gas supply line connected to the vacuum pump device; and a gas heating structure that heats the non-active gas via the non-active gas supply line.

10. The vacuum exhaust system according to claim 9, wherein The gas heating structure is a heater that heats the non-active gas supply line.

11. The vacuum exhaust system according to claim 9, wherein The gas heating structure is a pump housing that is heated by compression heat on the exhaust port side of the vacuum pump device.

12. The vacuum exhaust system according to any one of claims 6 to 8, wherein The gas introduction device includes an on-off valve that opens and closes the non-active gas supply line, The control device controls the opening and closing operation of the on-off valve.

13. The vacuum exhaust system according to any one of claims 6 to 8, wherein The gas introduction device includes a flow rate sensor that detects the flow rate of the non-active gas flowing in the non-active gas supply line, The control device determines the state of the on-off valve based on a flow rate signal transmitted from the flow rate sensor.

14. The vacuum exhaust system according to any one of claims 6 to 8, wherein The gas introduction device includes a combination of an on-off valve that opens and closes the non-active gas supply line and a flow rate sensor that detects the flow rate of the non-active gas flowing in the non-active gas supply line.

15. The vacuum exhaust system according to claim 6, wherein The flow rate control device includes an on-off valve that opens and closes the bypass line.

16. The vacuum exhaust system according to claim 6, wherein The flow control device is provided with a flow adjustment valve or a throttle hole installed in the bypass line.

Images