CN110546381A

CN110546381A - pump monitoring device, vacuum processing device, and vacuum pump

Info

Publication number: CN110546381A
Application number: CN201780089971.XA
Authority: CN
Inventors: 玉井雄介; 野田阳
Original assignee: Shimadzu Corp
Current assignee: Shimadzu Corp
Priority date: 2017-04-27
Filing date: 2017-04-27
Publication date: 2019-12-06
Also published as: JPWO2018198288A1; WO2018198288A1; US20200141415A1

Abstract

A pump monitoring device detects an abnormality in a plurality of vacuum pumps connected to the same chamber, and estimates that an abnormality has occurred in any one of the plurality of vacuum pumps based on a result of comparing signals indicating a rotation state of each pump rotor of the plurality of vacuum pumps.

Description

pump monitoring device, vacuum processing device, and vacuum pump

Technical Field

The invention relates to a pump monitoring device, a vacuum processing device and a vacuum pump.

Background

In a process such as dry etching or CVD in manufacturing a semiconductor or a liquid crystal panel, since a process is performed in a high-vacuum process chamber, a vacuum pump such as a turbo molecular pump can be used as a means for maintaining a high vacuum by exhausting gas in the process chamber. When a gas in a process chamber such as dry etching or CVD is exhausted, reaction products are accumulated in a pump along with the exhaust of the gas.

regarding the deposition of such reaction products, patent document 1 discloses a method for detecting a product deposited in a pump. In the deposit detection method disclosed in patent document 1, a current value of a motor that drives a rotating body of a pump to rotate is measured, and a warning is issued when a change amount of the measured value from an initial value of the motor current is equal to or greater than a predetermined value.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 5767632

Disclosure of Invention

Technical problem to be solved by the invention

However, in practice, the flow rate of gas discharged from a single process chamber varies greatly, and therefore the current value of the motor for driving the rotating body to rotate varies greatly with the variation in the flow rate of gas. Therefore, there are the following problems: if the motor current value varies due to variation in the gas flow rate, a warning is issued, and erroneous determination cannot be avoided.

Solution for solving the above technical problem

According to claim 1 of the present invention, a pump monitoring device that detects an abnormality in a plurality of vacuum pumps connected to the same chamber estimates that an abnormality has occurred in any one of the plurality of vacuum pumps based on a result of comparing signals indicating rotational states of respective pump rotors of the plurality of vacuum pumps.

according to the 2 nd aspect of the present invention, in the pump monitoring device according to the 1 st aspect, the signal indicating the rotation state is a motor current value of a motor that drives the pump rotor to rotate, and it is estimated that an abnormality has occurred in any one of the plurality of vacuum pumps based on a difference between the motor current values of the vacuum pumps that are different from each other.

According to a 3 rd aspect of the present invention, in the pump monitoring device according to the 1 st aspect, the pump rotor is magnetically supported by a magnetic bearing, and the signal indicating the rotation state is calculated based on a magnetic bearing control amount of the magnetic bearing.

According to the 4 th aspect of the present invention, the pump monitoring device according to the 1 st aspect is provided with an input unit to which a signal indicating the rotation state of the plurality of vacuum pumps is input from one or more vacuum processing devices, and the vacuum processing device is provided with a plurality of vacuum pumps that evacuate a chamber, and estimates that an abnormality has occurred in any one of the plurality of vacuum pumps for each of the vacuum processing devices.

according to the 5 th aspect of the present invention, a vacuum processing apparatus comprises: a chamber; a plurality of vacuum pumps that vacuum-exhaust the chamber; the pump monitoring device according to claim 1.

according to claim 6 of the present invention, a vacuum pump includes: the pump monitoring device of claim 1; a pump rotor driven to rotate by a motor; and an input unit to which a signal indicating a rotation state from another vacuum pump is input, wherein the pump monitoring device estimates a pump abnormality by comparing the signal indicating the rotation state of the pump rotor with the signal indicating the rotation state input from the input unit.

Effects of the invention

According to the present invention, erroneous determination in detecting an abnormality of a vacuum pump can be prevented.

Drawings

Fig. 1 is a diagram showing a semiconductor manufacturing apparatus according to embodiment 1.

fig. 2 is a sectional view showing details of the pump main body.

Fig. 3 is a diagram showing an example of the measured value of the motor current.

Fig. 4 is a block diagram showing a vacuum pump and a pump monitoring device.

Fig. 5 is a diagram showing a configuration of the displacement sensor.

Fig. 6 is a flowchart showing an example of the abnormality determination processing.

Fig. 7 is a block diagram illustrating magnetic bearing control.

Fig. 8 is a diagram showing an example of XY values.

Fig. 9 is a flowchart showing an example of the abnormality determination processing in embodiment 2.

Fig. 10 is a diagram illustrating embodiment 3.

Fig. 11 is a diagram illustrating embodiment 4.

Detailed Description

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

Embodiment 1

fig. 1 is a diagram showing a semiconductor manufacturing apparatus 10 according to embodiment 1. The semiconductor manufacturing apparatus 10 is a vacuum processing apparatus such as an etching apparatus. In the example shown in fig. 1, 2 vacuum pumps 1A and 1B are installed in the process chamber 100, but the present invention can be similarly applied to a case where 3 or more vacuum pumps are installed.

The vacuum pump 1A is attached to the process chamber 100 via a valve 3A, and the vacuum pump 1B is attached to the process chamber 100 via a valve 3B. The semiconductor manufacturing apparatus 10 includes a main control device 110, and the main control device 110 controls the entire manufacturing apparatus including the vacuum pumps 1A and 1B and the valves 3A and 3B. The main control device 110 includes a monitoring device 4, and the monitoring device 4 monitors whether or not the vacuum pumps 1A and 1B are abnormal. The vacuum pumps 1A and 1B are vacuum pumps of the same type, and each includes a pump main body 11 and a controller 12 for driving and controlling the pump main body 11. The controllers 12 of the vacuum pumps 1A and 1B are connected to a main controller 110 of the semiconductor manufacturing apparatus 10 via a communication line 40.

Fig. 2 is a sectional view showing details of the pump main body 11. The vacuum pumps 1A and 1B in the present embodiment are magnetic bearing type turbo molecular pumps, and a rotary body R is provided in a pump main body 11. The rotor R includes a pump rotor 14 and a rotor shaft 15 fastened to the pump rotor 14.

The pump rotor 14 has a plurality of stages of rotary blades 14a formed on the upstream side and a cylindrical portion 14b forming a spiral groove pump formed on the downstream side. In correspondence with these, a plurality of fixed vane stators 62 and cylindrical helical stators 64 are provided on the fixed side. In the example shown in fig. 2, the spiral stator 64 is formed with a spiral groove, but a spiral groove may be formed in the cylindrical portion 14 b. Each of the fixed-vane stators 62 is mounted on the base 60 via a spacer ring 63.

the rotor shaft 15 is magnetically supported by radial magnetic bearings 17A, 17B and axial magnetic bearing 17C provided on the base 60, and is driven to rotate by the motor 16. Each of the magnetic bearings 17A to 17C includes an electromagnet and a displacement sensor, and detects the levitation position of the rotor shaft 15 by the displacement sensor. The rotational speed of the rotor shaft 15 is detected by a rotational speed sensor 18. When the magnetic bearings 17A to 17C are not operating, the rotor shaft 15 is supported by emergency mechanical bearings 66a and 66 b.

The pump housing 61 formed with the intake port 61a is fixed to the base 60 by bolts. An exhaust port 65 is provided in the exhaust port 60a of the base 60, and a rear pump is connected to the exhaust port 65. When the rotor shaft 15 to which the pump rotor 14 is fastened is rotated at a high speed by the motor 16, gas molecules on the side of the intake port 61a are discharged to the side of the exhaust port 65.

The base 60 is provided with a heater 19 and a refrigerant pipe 20 through which a refrigerant such as cooling water flows. In the case of discharging gas that is likely to accumulate in the reaction product, in order to suppress accumulation of the product in the spiral groove pump portion and the downstream rotary vane 14a, the temperature is adjusted by turning on/off the heater 19 and turning on/off the refrigerant flowing through the refrigerant pipe 20 so that, for example, the temperature of the base near the fixing portion of the spiral stator reaches a predetermined temperature. Although not shown, the refrigerant pipe 20 is provided with an electromagnetic valve for turning on and off the refrigerant.

The operating conditions of the 2 vacuum pumps 1A and 1B installed in the same process chamber 100 can be considered to be almost the same. Further, pump maintenance due to accumulation of reaction products is also performed at the same timing. Therefore, it is considered that the deposition states of the reaction products in the vacuum pump 1A and the vacuum pump 1B are almost the same as the use time elapses.

Fig. 3 is a graph showing an example of the measured values of the motor currents of the vacuum pumps 1A and 1B, and shows the measured values in a state where the reaction product is deposited. In fig. 3, the horizontal axis represents time, and the vertical axis represents the motor current value. A line MA indicated by a solid line shows a motor current value of the vacuum pump 1A, and a line MB indicated by a broken line shows a motor current value of the vacuum pump 1B. Gas is introduced into the process chamber 100 during the period indicated by the reference numeral B, and the motor current values MA and MB are increased.

As shown in fig. 3, in an operating state in which the introduction and stop of the gas are repeated, the motor current value greatly fluctuates with the fluctuation of the gas flow rate. However, since the vacuum pumps 1A, 1B are vacuum pumps of the same model and the use conditions are almost the same, the motor current values MA, MB show almost the same tendency of change regardless of the change in the gas introduction amount, and the difference between the motor current values MA, MB is small, as shown in fig. 3.

However, in a state where the amount of the reaction product deposited is increased, a momentary increase in the motor current value is observed as shown by reference character a in fig. 3. This is presumed to be because if the accumulation of the reaction product continues, the gap between the cylindrical portion 14b and the spiral stator 64 shown in fig. 2 is reduced by the accumulation, and when the pump rotor 14 shakes, the cylindrical portion 14b and the spiral stator 64 occasionally contact each other, and a momentary increase in the motor current value occurs. In the example shown in fig. 3, the motor current value MA of the vacuum pump 1A rises instantaneously. Such a phenomenon occurs if the amount of the reaction product deposited becomes too large, and it is found that a failure due to the deposit (for example, a failure to start the pump due to contact between the cylindrical portion 14b and the helical stator 64) occurs for about several days to 2 weeks after the occurrence of the instantaneous increase in the motor current value.

Therefore, in the present embodiment, the difference between the motor current value MA of the vacuum pump 1A and the motor current value MB of the vacuum pump 1B is calculated, and when the magnitude of the difference exceeds a preset threshold value (for example, in the case of the situation shown by reference sign a in fig. 3), a warning is given to the user.

fig. 4 is a block diagram showing the configuration of the vacuum pumps 1A and 1B provided in the semiconductor manufacturing apparatus 10. The vacuum pumps 1A and 1B are vacuum pumps of the same type, the pump body 11 includes a motor 16, a magnetic bearing 17, and a rotation speed sensor 18, and the controller 12 includes a communication port 21, a magnetic bearing controller 22, a motor controller 23, and a storage 24. In fig. 4, the radial magnetic bearings 17A and 17B and the axial magnetic bearing 17C of fig. 2 are collectively referred to as a magnetic bearing 17. The main control device 110 includes a pump monitoring device 120, a display unit 130, and a communication port 44.

The motor control unit 23 estimates the rotation speed of the rotor shaft 15 based on the rotation signal detected by the rotation speed sensor 18, and controls the motor 16 to a predetermined target rotation speed based on the estimated rotation speed. Further, since the load on the pump rotor 14 increases if the gas flow rate increases, the motor current is controlled in accordance with the load to maintain the predetermined target rotation speed. The magnetic bearing 17 includes a bearing electromagnet and a displacement sensor for detecting a levitation position of the rotor shaft 15.

Fig. 5 is a diagram showing a configuration of the displacement sensor. The radial magnetic bearing 17A of fig. 2 is a magnetic bearing having 2 axes of the X axis and the Y axis, and includes a pair of displacement sensors X1a and X1b for the X axis and a pair of displacement sensors Y1a and Y1b for the Y axis. Similarly, the radial magnetic bearing 17B of fig. 2 is a magnetic bearing having 2 axes of the X axis and the Y axis, and includes a pair of displacement sensors X2a and X2B for the X axis and a pair of displacement sensors Y2a and Y2B for the Y axis. The axial magnetic bearing 17C is provided with a displacement sensor z for detecting axial displacement of the rotor shaft 15.

Returning to fig. 4, detection signals from the displacement sensors X1A, X1b, Y1A, Y1b, X2a, X2b, Y2a, Y2b, and z provided in the pump body 11 of the vacuum pump 1A are input to the magnetic bearing control unit 22 provided in the controller 12 of the vacuum pump 1A. Similarly, detection signals from the displacement sensors X1a, X1B, Y1a, Y1B, X2a, X2B, Y2a, Y2B, and z provided in the pump body 11 of the vacuum pump 1B are input to the magnetic bearing control unit 22 provided in the controller 12 of the vacuum pump 1B.

The magnetic bearing controller 22 of the controller 12 controls the excitation current of the magnetic bearing 17 so that the rotor shaft 15 is magnetically supported at the target levitation position based on the detection signals of the displacement sensors X1a, X1b, Y1a, Y1b, X2a, X2b, Y2a, Y2b, and z. The storage unit 24 of the controller 12 stores parameters necessary for motor control and magnetic bearing control, and also stores model data of the vacuum pumps 1A and 1B.

As described above, the pump monitoring device 120 provided in the main control device 110 is a device for monitoring whether or not an abnormality (i.e., excessive accumulation of reaction products) occurs in the vacuum pumps 1A and 1B installed in the process chamber 100. The controller 12 of the vacuum pumps 1A and 1B communicates with the main control device 110 to transmit and receive information. As an example shown in fig. 4, a case where signals are exchanged by serial communication is shown. The controller 12 is provided with a communication port 21, and the main control device 110 is also provided with a communication port 44. The communication port 21 of the controller 12 is connected to the communication port 44 of the main control device 110 via the communication line 40.

(description of monitoring method)

The pump monitoring device 120 uses signals indicating the rotation states of the respective pump rotors 14 as information for detecting an abnormality of the vacuum pumps 1A, 1B. In the present embodiment, a case will be described in which the motor current values MA and MB of the vacuum pumps 1A and 1B are used as signals indicating the rotation state of the pump rotor 14.

The motor control unit 23 of the controller 12 calculates the rotation speed of the motor 16 based on the detection value of the rotation speed sensor 18 and performs feedback control so that the detected rotation speed reaches the target rotation speed. In a state where a series of processes are performed as shown in fig. 3, the motor control section 23 performs normal operation control to maintain the rotational speed at the rated rotational speed. As described above, since the gas is introduced into the process chamber 100 in the section indicated by reference numeral B, the load on the pump rotor 14 is also increased. Since the motor control unit 23 performs control to maintain the motor rotation speed at the rated rotation speed, the motor current values MA and MB increase as the gas load increases.

The motor current values MA, MB of the vacuum pumps 1A, 1B acquired via the communication line 40 are input to the pump monitoring apparatus 120. The pump monitoring device 120 calculates a difference Δ M (MA-MB) between the motor current values MA and MB. When the magnitude | Δ M | of the difference Δ M exceeds a predetermined threshold value α, the pump monitoring device 120 determines that there is an abnormality. For example, the difference Δ M between the motor current values MA and MB at time t1 in fig. 3 satisfies | Δ M | < α, and is not determined to be abnormal, but is determined to be abnormal at time t2 when | Δ M | > α.

The vacuum pumps 1A and 1B are used in almost the same environment, and the deposition conditions of the reaction products are almost the same. If the amount of the reaction product deposited becomes too large, a momentary rise in the motor current value occurs, which is estimated to be caused by incidental contact between the cylindrical portion 14b and the helical stator 64. However, such a rise in the motor current value occurs sporadically, and it is not known which of the vacuum pumps 1A, 1B occurs. In the present embodiment, since the magnitude | Δ M | of the difference Δ M is compared with the threshold value α, even when an abnormality (i.e., an increase in the motor current value) occurs in either of the vacuum pumps 1A and 1B, the abnormality can be detected.

The threshold value α may be set in advance, or may be set based on the motor current values MA and MB of the vacuum pumps 1A and 1B during actual operation. When the threshold value α is set based on the motor current values MA and MB in the operating state, the threshold value α may be set based on the motor current values MA and MB in the initial state in which the use period is short from the start of use of the vacuum pumps 1A and 1B, or may be set based on the motor current values MA and MB from the time point of start of use to the time when abnormality is determined.

Since the amount of deposition of the product is small in the initial state, the threshold σ can be set without being affected by the deposition of the product. Further, in the initial state, too, a momentary rise in the motor current value as shown by reference character a of fig. 3 hardly occurs. With respect to the motor current values MA, MB, the pump monitoring device 120 acquires a large amount of data over time, and calculates the standard deviation σ of the difference Δ M based on the data. Since | Δ M | in the abnormal state is significantly larger than | Δ M | in the normal state, the threshold value is set to a value larger than the standard deviation σ, for example, 6 σ, in order to avoid erroneous detection.

Fig. 6 is a flowchart showing an example of the abnormality determination process performed by the pump monitoring device 120. In step S100, a threshold α is set based on the motor current values MA and MB in the initial state. Specifically, after the vacuum pumps 1A and 1B are attached to the process chamber 100, the motor current values MA and MB are sampled at regular time intervals in an initial state from the start of operation of the pumps to a predetermined period. In this case, the motor current values MA and MB are sampled at the same timing. The difference Δ M is obtained as MA-MB for the obtained pairs of motor current values MA and MB, and the standard deviation σ of the difference Δ M is calculated. Then, 6 σ is set as the threshold value α. The threshold value α is 6 σ stored in a storage unit (not shown) provided in the pump monitoring device 120 in fig. 4.

Next, the motor current values MA, MB are read in step S110, and the magnitude | Δ M | of the difference Δ M is calculated in subsequent step S120. In step S130, it is determined whether or not the magnitude relation between | Δ M | and the threshold α is | Δ M | > α. If it is determined in step S130 that | Δ M | > α, the process proceeds to step S140 to execute warning processing. For example, by displaying a warning on the display unit 130 of the main control device 110, the user is notified that maintenance of the vacuum pumps 1A and 1B installed in the process chamber 100 is required.

On the other hand, if it is determined in step S130 that | Δ M | ≦ α, the process returns to step S110, and the process from step S110 to step S130 is executed again. The processing from step S110 to step S130 is repeatedly executed at predetermined time intervals until it is determined yes in step S130.

(C1) As described above, the pump monitoring apparatus 120 that detects an abnormality in the plurality of vacuum pumps 1A, 1B connected to the same process chamber 100 estimates that an abnormality has occurred in any one of the vacuum pumps 1A, 1B based on the result of comparing the signals indicating the rotation state of each of the pump rotors 14 of the plurality of vacuum pumps 1A, 1B.

Since the vacuum pumps 1A and 1B are connected to the same process chamber 100, the pump states such as the amount of deposition of reaction products become almost the same, and even when the motor current value fluctuates due to fluctuation of the gas flow rate, the signal indicating the rotation state of the pump rotor 14 tends to be the same. Therefore, by comparing the signals indicating the rotation state, it is possible to easily estimate that an abnormality has occurred in either of the vacuum pumps 1A and 1B in a state where the signals indicating the rotation state (motor current values MA and MB in the example of fig. 3) are deviated from each other as in the case of time t2 in fig. 3, and to prevent erroneous determination as in the conventional case.

(C2) For example, the motor current values MA and MB of the motor 16 for driving the pump rotor 14 to rotate can be used as the signals indicating the above-described rotation states. In this case, it is estimated that an abnormality has occurred in either of the vacuum pumps 1A, 1B, based on the difference between the motor current values MA, MB of the vacuum pumps 1A, 1B different from each other, for example, by comparing the magnitude | Δ M | of the difference Δ M between the motor current values MA, MB with the threshold value α.

(C5) As shown in fig. 1, the semiconductor manufacturing apparatus 10, which is a vacuum processing apparatus including a process chamber 100 and a plurality of vacuum pumps 1A and 1B for evacuating the process chamber 100, may further include the pump monitoring apparatus 120. The operator can accurately know the maintenance timing of the vacuum pumps 1A and 1B installed in the process chamber 100 by the warning from the pump monitoring apparatus 120.

In the above-described embodiment, when the threshold α at the time of determining whether or not there is an abnormality is set, the standard deviation σ of the difference MA-MB is used to set α to 6 σ, but the average value of the differences may be used.

In the above-described embodiment, the case where 2 vacuum pumps are installed in the process chamber 100 was described as an example, but the present invention can also be applied to a case where 3 or more vacuum pumps are installed. Even when 3 or more vacuum pumps are installed, since each vacuum pump is used under the same conditions, the pump monitoring device 120 warns that maintenance is required for all of the plurality of vacuum pumps installed in the process chamber 100 when an abnormality (i.e., excessive accumulation of reaction products) is detected in any one of the plurality of vacuum pumps.

The pump monitoring apparatus 120 acquires a motor current value from each of 2 vacuum pumps installed in the process chamber 100, and determines whether or not the magnitude | Δ M | of the difference between the 2 motor current values is | Δ M | > α. All of the plurality of vacuum pumps were judged as 2 of them. For example, when 5 vacuum pumps 1A, 1B, 1C, 1D, and 1E are installed in the process chamber 100, it is determined whether or not | Δ M | > α is satisfied for 3 types of combinations of (1A, 1B), (1C, 1D), (1E, and 1A). Then, when | Δ M | > α is set for at least 1 of the 3 types of combinations, a maintenance warning is issued to all of the 5 vacuum pumps 1A to 1E.

Since all the vacuum pumps 1A, 1B, 1C, 1D, and 1E attached to the process chamber 100 are included in the 3 types of combinations (1A, 1B), (1C, 1D), and (1E, 1A), the abnormality detection processing described above is performed on the 3 types of combinations, and thus abnormality determination is performed on all the vacuum pumps 1A to 1E.

Embodiment 2

In the above-described embodiment 1, the motor current values MA and MB are used as the signals indicating the rotation state of the pump rotor 14, but in the embodiment 2, the signals indicating the rotation state are calculated based on the magnetic bearing control amount generated based on the displacement signal of the displacement sensor. As shown in fig. 5, displacement sensors for detecting the levitation position of the rotor shaft 15 are provided in the radial magnetic bearings 17A, 17B, and 17C, respectively. The following description will be made of a case where displacement signals of the displacement sensors X2a, X2b, Y2a, and Y2b for detecting the levitation position in the radial direction are used as signals indicating the rotation state.

As shown in fig. 5, the radial magnetic bearing 17A includes two pairs of electromagnets arranged so as to sandwich the rotor shaft 15, and a pair of displacement sensors X2a and X2b is provided for one of the pairs of electromagnets arranged in the X-axis direction, and a pair of displacement sensors Y2a and Y2b is provided for the other pair of electromagnets arranged in the Y-axis direction.

fig. 7 is a block diagram illustrating magnetic bearing control related to the displacement sensors X2a and X2 b. The block diagrams of the displacement sensors Y2a and Y2b are also exactly the same as those in fig. 7. The displacement signals of the displacement sensors X2a and X2b vary depending on the size of the gap between the displacement sensors X2a and X2b and the rotor shaft 15. The displacement signals from the displacement sensors X2a, X2b are input to the differential amplifier 602. The difference of these signals, i.e., the differential signal Vdif, is output from the differential amplifier 602.

The differential signal Vdif is input to the PID control circuit 53. The PID control circuit 53 performs PID calculation in accordance with the value of the current flowing through the electromagnet 37X so that the differential signal Vdif becomes zero, that is, the rotor shaft 15 is supported at the center of the displacement sensors X2a and X2b, and outputs the result to the current amplifier 55 as a magnetic bearing control amount. The current amplifier 55 supplies an electromagnet current corresponding to the input magnetic bearing control amount to the electromagnet 37 x.

In the present embodiment, the XY value, which is a signal indicating the rotational state of the pump rotor 14, is calculated based on the magnetic bearing control amount output from the PID control circuit 53 to the current amplifier 55. Hereinafter, the magnetic bearing control amount in the x-axis direction is represented by PID-IX, and the magnetic bearing control amount in the y-axis direction is represented by PID-IY. The pump monitoring device 120 reads the magnetic bearing control amounts PID-IX and PID-IY from the vacuum pumps 1A and 1B, respectively, and calculates XY values represented by equation (1).

XY＝{(PID-IX)+(PID-IY)} (1)

The XY value represented in the formula (1) is introduced as an index representing a force applied to the pump rotor 14 in the horizontal direction, that is, representing a deviation of the shaft center of the pump rotor 14 from the target levitation position. The larger the horizontal force, that is, the larger the deviation of the shaft center of the pump rotor 14 from the target levitation position, the larger the XY value. If the amount of deposition of the reaction product increases and the cylindrical portion 14b comes into contact with the spiral stator 64 to apply a force to the pump rotor 14, the rotational state of the pump rotor 14, that is, the deviation of the axial center increases, and the XY value also increases.

Fig. 8 is a diagram showing an example of XY values. Fig. 8 shows XY values detected by 2 vacuum pumps 1A and 1B installed in the same process chamber, and the pump state is almost the same as that in the case shown in fig. 3. In fig. 8, the vertical axis represents XY values, the horizontal axis represents time, a line SA indicated by a solid line shows XY values of the vacuum pump 1A, and a line SB indicated by a broken line shows XY values of the vacuum pump 1B.

The variation pattern of the XY values SA and SB in each section C is the same pattern in any section C. However, the magnitude | Δ XY | of the difference between the XY value SA and the XY value SB at time t3 becomes larger than | Δ XY | at other times. Such a momentary rise in | Δ XY | is considered to be caused by the contact between the cylindrical portion 14b and the helical stator 64. In fact, when the motor current value instantaneously rises as indicated by reference character a in fig. 3, the instantaneous rise of | Δ XY | as shown in fig. 8 also occurs at the same time.

Further, since the pump rotor 14 is also shaken when external disturbance acts on the pump rotor 14 or when the gas load is rapidly changed, the magnetic bearing control amounts PID-IX and PID-IY vary so as to suppress the shaking. Therefore, the XY value also fluctuates to some extent in a state where the cylindrical portion 14b is not in contact with the helical stator 64.

In the present embodiment, the pump monitoring device 120 calculates the XY values of the vacuum pumps 1A and 1B, respectively. Then, when the magnitude | Δ XY | of the calculated difference Δ XY between the 2 XY values is larger than a predetermined threshold value, it is warned that an abnormality (that is, excessive accumulation of a reaction product) has occurred in either of the vacuum pumps 1A and 1B. That is, the need for maintenance of the vacuum pumps 1A, 1B is warned. Note that, as for the method of setting the threshold α, it is considered that, similarly to the case of embodiment 1, for example, when the standard deviation of the difference Δ XY is σ, it is sufficient to set 6 σ as the threshold α.

Fig. 9 is a flowchart showing an example of the abnormality determination processing in embodiment 2. In step S200, as in the case of embodiment 1, a threshold α is set based on the XY values SA and SB in the initial state. The motor current values MA and MB in embodiment 1 may be replaced with the XY values SA and SB, and the same processing as in step S100 in fig. 6 may be performed, and detailed description thereof will be omitted. The calculated threshold value α is stored in a storage unit (not shown) provided in the pump monitoring device 120.

On the other hand, if it is determined in step S230 that | Δ XY | ≦ α, the process returns to step S210, and the process from step S210 to step S230 is executed again. The processing from step S210 to step S230 is repeatedly executed at predetermined time intervals until it is determined yes in step S230.

(C3) As described above, in embodiment 2, the XY value, which is a signal indicating the rotation state, is calculated based on the magnetic bearing control amounts PID-IX and PID-IY when the pump rotor 14 is magnetically suspended and supported by the magnetic bearings. Then, XY values SA and SB are calculated for the vacuum pumps 1A and 1B, respectively, and the magnitude | Δ XY | of the difference between these values is compared with a threshold value α, thereby estimating that an abnormality has occurred in either of the vacuum pumps 1A and 1B.

The XY value indicates the deviation of the axial center of the pump rotor 14 from the target levitation position, and if the amount of deposition of the reaction product increases and the cylindrical portion 14b comes into contact with the spiral stator 64 to apply a force to the pump rotor 14, the deviation of the axial center, which is the rotation state of the pump rotor 14, becomes large, and the XY value also becomes large. Therefore, the vacuum pumps 1A and 1B can easily detect an abnormality (i.e., excessive accumulation of a reaction product) in either of the vacuum pumps 1A and 1B by comparing the magnitude | Δ XY | of the difference between the respective XY values with the threshold value α.

Further, it is also possible to detect that an abnormality has occurred in either of the vacuum pumps 1A, 1B using both the XY value difference Δ XY and the motor current value difference Δ M.

In the above description, in the case of detecting the contact between the pump rotor 14 and the helical stator 64, the displacement signals of the displacement sensors X2a, X2b, Y2a, Y2b that are close to the pump rotor 14 in the axial direction are used, but the displacement signals of the displacement sensors X1a, X1b, Y1a, Y1b may be used.

Embodiment 3

Fig. 10 is a diagram for explaining embodiment 3, and is a block diagram showing the configuration of vacuum pumps 1A and 1B provided in the semiconductor manufacturing apparatus 10, similarly to fig. 4. In the above-described embodiments 1 and 2, the pump monitoring apparatus 120 is provided in the main control apparatus 110 of the semiconductor manufacturing apparatus 10. On the other hand, in embodiment 3, the pump monitoring device 120 is provided in the controller 12 of each vacuum pump 1A, 1B. The other configuration is the same as that shown in fig. 4.

The pump monitoring apparatus 120 provided in the controller 12 of the vacuum pump 1A acquires a signal showing the rotational state of the pump rotor 14 of the vacuum pump 1A, and acquires a signal showing the rotational state of the pump rotor 14 of the other vacuum pump 1B from the vacuum pump 1B via the communication line 40. Likewise, the pump monitoring device 120 provided in the controller 12 of the vacuum pump 1B acquires a signal showing the rotational state of the pump rotor 14 of the vacuum pump 1B, and acquires a signal showing the rotational state of the pump rotor 14 of the other vacuum pump 1A from the vacuum pump 1A via the communication line 40.

The signal indicating the rotation state of the pump rotor 14 may be the motor current values MA and MB obtained from the motor controller 23 described in embodiment 1, or may be XY values calculated from the magnetic bearing control amounts PID-IX and PID-IY obtained from the magnetic bearing controller 22 described in embodiment 2. Even when either signal is used, each of the vacuum pumps 1A and 1B detects that an abnormality (i.e., excessive accumulation of a reaction product) has occurred in either of the vacuum pumps 1A and 1B.

The abnormality detection results detected by the vacuum pumps 1A and 1B are transmitted to the main control device 110 via the communication line 40. If an abnormality detection result is input from at least one of the vacuum pumps 1A, 1B, the main control device 110 displays a warning display to notify that the maintenance timing of the vacuum pumps 1A, 1B has come.

(C6) In the present embodiment, as shown in fig. 10, a pump monitoring device 120 is provided in the controller 12 of the vacuum pump 1A. The motor current value MB, which is a signal indicating the rotation state from the other vacuum pump 1B, is input to the communication port 21, which is a signal input unit of the controller 12. Then, the pump monitoring device 120 estimates a pump abnormality by comparing the motor current value MA, which is a signal indicating the rotation state of the pump rotor 14 of the vacuum pump 1A, with the motor current value MB input from the communication port 21, that is, by comparing the difference Δ M ═ Δ M | of the magnitude of MA-MB with the threshold value α.

In this way, the vacuum pumps 1A and 1B estimate the pump abnormality, and the redundancy of abnormality detection is increased by using both estimation results, so that the abnormality of the vacuum pumps 1A and 1B can be reliably detected.

4 th embodiment

Fig. 11 is a diagram illustrating embodiment 4. In embodiment 4, the pump monitoring apparatus 120 detects occurrence of an abnormality (i.e., excessive accumulation of reaction products) in the vacuum pumps installed in the respective processing chambers of the plurality of semiconductor manufacturing apparatuses. In the example shown in FIG. 11, the pump monitoring apparatus 120 monitors the vacuum pumps 1A to 1F installed in the process chambers 100A to 100C of the 3 semiconductor manufacturing apparatuses 10A, 10B, 10C.

Each of the semiconductor manufacturing apparatuses 10A to 10C is provided with a wireless communication apparatus 140. The pump monitoring device 120 is also provided with a wireless communication device 200, and information can be transmitted and received between the communication device 140 and the communication device 200. The pump monitoring device 120 can acquire signals indicating the rotation states of the pump rotors of the vacuum pumps 1A to 1F from the respective semiconductor manufacturing apparatuses 10A to 10C via the communication devices 140 and 200. Hereinafter, a case where a signal indicating a rotation state is a motor current value will be described as an example.

Even in the case where 3 semiconductor manufacturing apparatuses 10A to 10C are the same apparatus, when the latest maintenance timings of the vacuum pumps 1A to 1F provided in the respective semiconductor manufacturing apparatuses 10A to 10C are different, the next maintenance timings of the vacuum pumps in the respective semiconductor manufacturing apparatuses 10A to 10C are different. Therefore, the pump monitoring apparatus 120 detects an abnormality of the vacuum pump for each of the semiconductor manufacturing apparatuses 10A to 10C.

When determining an abnormality of the vacuum pumps 1A, 1B, the motor current values MA, MB of the vacuum pumps 1A, 1B are acquired from the semiconductor manufacturing apparatus 10A. The abnormality detection processing based on the motor current values MA and MB is the same as the abnormality detection processing shown in fig. 6 of embodiment 1. That is, calculation unit 210 sets threshold α for determining an abnormality based on motor current values MA and MB in the initial state. The threshold value α is stored in the storage unit 220. The calculation unit 210 acquires the motor current values MA and MB from the semiconductor manufacturing apparatus 10A at predetermined time intervals, and determines whether or not the magnitude | Δ M | ═ MA-MB | of the difference between the motor current values MA and MB is | Δ M | > α. Then, when | Δ M | > α, it is determined that an abnormality has occurred in either of the vacuum pumps 1A, 1B, and a warning display is displayed on the display unit 230 to prompt maintenance of the vacuum pumps 1A, 1B.

The vacuum pumps 1C and 1D and 1E and 1F of the semiconductor manufacturing apparatuses 10B and 10C also perform the same abnormality determination process as in the case of the vacuum pumps 1A and 1B of the semiconductor manufacturing apparatus 10A for the respective semiconductor manufacturing apparatuses 10B and 10C.

(C4) In embodiment 4, the pump monitoring apparatus 120 includes the communication apparatus 200 as an input unit to which the motor current values MA to MF from the vacuum pumps 1A to 1F provided in the one or more semiconductor manufacturing apparatuses 10A, 10B, and 10C, respectively, are input, and it is estimated for each of the semiconductor manufacturing apparatuses 10A, 10B, and 10C that an abnormality has occurred in any one of the 2 vacuum pumps provided in the respective semiconductor manufacturing apparatuses.

By providing such a pump monitoring apparatus 120, it is possible to detect an abnormality in the vacuum pump provided in each of the plurality of semiconductor manufacturing apparatuses 10A, 10B, and 10C.

In the example shown in fig. 11, the communication device 200 is of a wireless type, but may be of a wired type. By adopting a wireless system, remote unified management can be easily performed.

Although various embodiments have been described above, the present invention is not limited to these. Other embodiments that can be conceived within the scope of the technical idea of the present invention are also included within the scope of the present invention. Further, a plurality of embodiments may be combined.

Description of the reference numerals

1A, 1B, 1C, 1D, 1E, 1F … vacuum pump

10 … semiconductor manufacturing device

11 … Pump body

12 … controller

14 … Pump rotor

16 … motor

17 … magnetic bearing

17A, 17B … radial magnetic bearing

17C … axial magnetic bearing

21. 44 … communication port

22 … magnetic bearing controller

23 … Motor control part

100. 100A … processing chamber

110 … master control device

120 … pump monitoring device

MA, MB … motor current value

SA, SB … XY value

X1a, X1b, Y1a, Y1b, X2a, X2b, Y2a, Y2b, z … displacement sensors.

Claims

1. A pump monitoring device for detecting abnormality of a plurality of vacuum pumps connected to the same chamber,

And estimating that an abnormality occurs in any one of the plurality of vacuum pumps based on a result of comparing signals indicating rotational states of respective pump rotors of the plurality of vacuum pumps.

2. Pump monitoring device according to claim 1,

The signal indicating the rotation state is a motor current value of a motor that drives the pump rotor to rotate,

it is estimated that an abnormality occurs in any one of the plurality of vacuum pumps based on a difference in the motor current values of the vacuum pumps that are different from each other.

3. Pump monitoring device according to claim 1,

The pump rotor is supported in a magnetic levitation manner by magnetic bearings,

Calculating a signal representing the rotation state based on a magnetic bearing control amount of the magnetic bearing.

4. Pump monitoring device according to claim 1,

The vacuum processing apparatus includes an input unit to which signals indicating the rotation states of the plurality of vacuum pumps are input from one or more vacuum processing apparatuses including a plurality of vacuum pumps that vacuum-evacuate a chamber,

It is estimated that an abnormality occurs in any one of the plurality of vacuum pumps for each of the vacuum processing apparatuses.

5. A vacuum processing apparatus is characterized by comprising:

A chamber;

A plurality of vacuum pumps that vacuum-exhaust the chamber;

the pump monitoring device of claim 1.

6. A vacuum pump is characterized by comprising:

The pump monitoring device of claim 1;

A pump rotor driven to rotate by a motor;

An input unit to which a signal indicating a rotation state from another vacuum pump is input,

the pump monitoring device estimates a pump abnormality by comparing a signal indicating a rotation state of the pump rotor with a signal indicating a rotation state input from the input unit.