Pump monitoring device and vacuum pump
阅读说明:本技术 泵监视装置及真空泵 (Pump monitoring device and vacuum pump ) 是由 渡边耕太 于 2019-07-26 设计创作,主要内容包括:本发明提供一种泵监视装置及真空泵。泵监视装置,其高精度地判定泵异常。泵监视装置是对针对处理对象实施各种工艺的工艺腔室内进行排气的真空泵(1)的监视装置,其包括:获取部(24a),获取表示真空泵(1)的运转状态的物理量;比较部(24d),对马达电流值的实测波形与基准波形进行比较;以及判定部(24e),基于比较部(24d)中的比较结果,判定真空泵(1)的负荷。(The invention provides a pump monitoring device and a vacuum pump. A pump monitoring device determines a pump abnormality with high accuracy. A pump monitoring device is a monitoring device for a vacuum pump (1) for exhausting gas from a process chamber in which various processes are performed on a processing object, and comprises: an acquisition unit (24a) that acquires a physical quantity indicating the operating state of the vacuum pump (1); a comparison unit (24d) that compares the actual measurement waveform of the motor current value with a reference waveform; and a determination unit (24e) that determines the load on the vacuum pump (1) based on the comparison result in the comparison unit (24 d).)
1. A pump monitoring apparatus for a vacuum pump that exhausts a process chamber in which various processes are performed on a processing target, the pump monitoring apparatus comprising:
an acquisition unit that acquires a physical quantity indicating an operating state of the vacuum pump;
a comparison unit that compares an actually measured waveform of the physical quantity with a reference waveform; and
and a determination unit that determines an abnormality of the vacuum pump caused by an increase in load, based on a result of the comparison by the comparison unit.
2. The pump monitoring device of claim 1,
the comparison unit compares the reference waveform selected for each process with the measured waveform.
3. The pump monitoring device according to claim 1 or 2,
the reference waveform is obtained based on a signal waveform of the physical quantity in a predetermined period after the vacuum pump is started.
4. The pump monitoring device according to claim 1 or 2,
the comparison unit calculates an average value of the physical quantities of the actual measurement waveform and the reference waveform in a time range in which the physical quantity in one process becomes maximum, calculates a difference between the average values, and compares the waveforms.
5. The pump monitoring device according to claim 1 or 2,
when the signal waveform of the physical quantity obtained when the same process is successively performed on each of the plurality of the processing objects is defined as a unit waveform,
the reference waveform and the measured waveform each include a plurality of unit waveforms that repeat over a predetermined period, and
the comparison unit compares the reference waveform including the plurality of unit waveforms with the measured waveform.
6. The pump monitoring device according to claim 1 or 2,
the physical quantity is a current value of a motor that rotationally drives a rotor of the vacuum pump.
7. A vacuum pump, comprising:
a pump body having a rotor, a stator, and a motor for rotationally driving the rotor; and
a pump controller including the pump monitoring device according to any one of claims 1 to 6, and performing drive control of the motor.
Technical Field
The present invention relates to a pump monitoring device and a vacuum pump equipped with the pump monitoring device.
Background
In a process such as dry etching or Chemical Vapor Deposition (CVD) for manufacturing a semiconductor or a liquid crystal panel, a process chamber (process chamber) is treated in a high vacuum, and therefore, a vacuum pump such as a turbo molecular pump is used to evacuate gas in the process chamber to maintain a high vacuum. When a gas in a process chamber such as dry etching or CVD is exhausted, a reaction product is accumulated in a pump along with the exhaust of the gas.
Regarding the accumulation of such reaction products,
[ Prior art documents ]
[ patent document ]
[ patent document 1] Japanese patent No. 5767632 publication
Disclosure of Invention
[ problems to be solved by the invention ]
However, in practice, even in a single process, the flow rate of the gas to be exhausted greatly fluctuates, and therefore the current value of the motor that rotationally drives the rotating body also greatly fluctuates with the fluctuation in the flow rate of the gas. Therefore, erroneous determination cannot be avoided.
[ means for solving problems ]
(1) A pump monitoring apparatus according to the present invention is a monitoring apparatus for a vacuum pump that exhausts a process chamber in which various processes are performed on a processing target, and includes: an acquisition unit that acquires a physical quantity indicating an operating state of the vacuum pump; a comparison unit that compares an actually measured waveform of the physical quantity with a reference waveform; and a determination unit that determines an abnormality of the vacuum pump caused by an increase in load, based on a result of the comparison by the comparison unit.
(2) The comparing section of the pump monitoring apparatus preferably compares the reference waveform selected for the process with the measured waveform.
(3) The reference waveform of the pump monitoring device is preferably acquired based on a signal waveform of the physical quantity within a predetermined time after the vacuum pump is started.
(4) The comparing section of the pump monitoring device preferably calculates an average value of the physical quantities of the actual measurement waveform and the reference waveform in a time range in which the physical quantity in one process becomes maximum, and calculates a difference between the average values to perform waveform comparison.
(5) In a preferred aspect of the pump monitoring device, when a signal waveform of the physical quantity obtained when the same process is continuously performed on each of the plurality of processing objects is defined as a unit waveform, the reference waveform and the measured waveform each include a plurality of unit waveforms that overlap for a predetermined period, and the comparison unit compares the reference waveform and the measured waveform that include the plurality of unit waveforms.
(6) The physical quantity of the pump monitoring device is preferably a current value of a motor that rotationally drives a rotor of the vacuum pump.
(7) A vacuum pump according to another aspect of the present invention includes: a pump body having a rotor, a stator, and a motor for rotationally driving the rotor; and a pump controller including the pump monitoring device and performing drive control of the motor.
[ Effect of the invention ]
According to the present invention, it is possible to accurately determine an abnormality in the load of the vacuum pump due to a process in the process chamber, for example, an abnormality due to an increase in the pump load accompanying the generation of deposits of impurities.
Drawings
Fig. 1 is a diagram showing a vacuum processing apparatus according to a first embodiment.
Fig. 2 is a sectional view showing details of the pump body.
Fig. 3(a) is a block diagram showing a vacuum pump and a pump monitoring device, and fig. 3(b) is a functional block diagram of a pump monitoring unit.
Fig. 4 is a diagram showing a measured waveform of a motor current value and a reference waveform.
Fig. 5 is a flowchart showing an example of a main flow of the operation control process of the vacuum pump.
Fig. 6 is a flowchart showing an example of the pump monitoring process according to the first embodiment.
Fig. 7 is a flowchart showing an example of the abnormality determination processing.
Fig. 8(a) and 8(b) are diagrams showing an actually measured waveform of a motor current value and a reference waveform.
Fig. 9 is a flowchart showing an example of the pump monitoring process according to the second embodiment.
Description of the symbols
1: vacuum pump
2: process chamber
3: vacuum valve
10: vacuum processing apparatus
11: pump body
12: pump controller
14: pump rotor
16: motor with a stator having a stator core
17: magnetic bearing
17A, 17B: radial magnetic bearing
17C: axial magnetic bearing
22: magnetic bearing control unit
23: motor control unit
24: pump monitoring unit
24 a: reference waveform acquisition unit
24 b: waveform comparing section
24 c: abnormality determination unit
25: storage unit
41: measured waveform
42: reference waveform
100: main controller
Detailed Description
Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
First embodiment
Fig. 1 is a diagram showing a
Fig. 2 is a sectional view showing details of the
The pump rotor 14 has a plurality of rotary blades 14a formed on the upstream side and a cylindrical portion 14b forming a screw pump formed on the downstream side. A plurality of fixed vane stators 62 and a cylindrical screw stator 64 are provided on the fixed side corresponding to the rotary vane 14a and the cylindrical portion 14 b. There are a form in which a thread groove is formed on the inner peripheral surface of the screw stator 64 and a form in which a thread groove is formed on the outer peripheral surface of the cylindrical portion 14 b. Each of the fixed-vane stators 62 is mounted on the base 60 via a spacer ring (spacer ring) 63.
The rotor shaft 15 is magnetically supported by radial magnetic bearings 17A, radial magnetic bearings 17B, and axial magnetic bearings 17C provided on the base 60, and is rotationally driven 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 do not operate, the rotor shaft 15 is supported by the emergency mechanical bearing 66a and the mechanical bearing 66 b.
A pump casing 61 having an air inlet 61a formed therein is fixed to the base 60 by a bolt. An exhaust port 65 is provided at the exhaust port 60a of the base 60, and the exhaust port 65 is connected to a backing pump (back pump). 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 suction port 61a side are discharged toward the exhaust port 65 side.
The base 60 is provided with a heater 19 and a refrigerant pipe 20 through which a refrigerant such as cooling water flows. The refrigerant pipe 20 is connected to a refrigerant supply pipe, not shown, and the flow rate of the refrigerant to the refrigerant pipe 20 can be adjusted by on-off control of an electromagnetic on-off valve provided in the refrigerant supply pipe. When the gas in which the reaction product is likely to accumulate is exhausted, the temperature is adjusted so that, for example, the base temperature in the vicinity of the screw stator fixing portion becomes a predetermined temperature by turning on/off the heater 19 and turning on/off the flow rate of the refrigerant flowing through the refrigerant pipe 20 in order to suppress the accumulation of the reaction product on the screw groove pump portion or the downstream rotary vane 14 a.
Fig. 3(a) and 3(b) are block diagrams showing the configuration of the
The
The
The magnetic bearing 17 includes a bearing electromagnet and a displacement sensor for detecting a levitation position of the rotor shaft 15.
As described above, the pump monitoring unit 24 provided in the
Referring to fig. 3(b), the pump monitoring unit 24 includes: an acquisition unit 24a that acquires a physical quantity indicating the operating state of the
The
(description of monitoring method)
The pump monitoring unit 24 uses a signal indicating the rotation state of the pump rotor 14 as information for detecting an abnormality of the
The
The motor current value of the
Fig. 4 is a diagram showing an example of a time-series waveform of a motor current value when the same vacuum processing process is continuously repeated in the
In fig. 4, the process P1 for the first substrate is performed between time t1 and time t2, the process P2 for the second substrate is performed between time t2 and time t3, and the process P3 for the third substrate is performed between time t3 and
When the pressure of the
In the pump monitoring unit 24 of the first embodiment, the process is started after the
The reference waveform is, for example, the following (1) and (2).
(1) A signal waveform of a motor current value obtained when the same process (for example, an etching process) is performed for each of a plurality of processing objects is defined as a unit waveform. Referring to fig. 4, the signal waveform of the motor current value in the interval of process P1 from time t1 to time t2 is a unit waveform. The reference waveform is a waveform obtained by collecting N unit waveforms in a predetermined period during which the processes P1, P2, and P3 … … are performed. The predetermined period is a period in which the influence of the deposit does not appear, as described above.
(2) The N reference waveforms obtained in the predetermined period are substantially the same pattern. A waveform having one averaged signal pattern may be set as the reference waveform based on the N unit waveforms. In the description with reference to fig. 4, for example, the average value of the signal patterns in each of three sections from time t1 to time t2 to time t3 to time t4 may be used as the reference waveform.
In the following description, the reference waveform described in (1) above will be described as being compared with the actually measured waveform.
The actual measurement waveform of the degree of coincidence with the calculated pattern of the reference waveform is a repetitive pattern of the motor current values obtained within a predetermined period after the reference waveform is generated. The measured waveform is compared with a reference waveform having a plurality of signal patterns as described in (1). Alternatively, each of the plurality of unit waveforms of the actually measured waveform is compared with the reference waveform which is the unit waveform of one signal pattern as in the above-mentioned (2).
The pump monitoring unit 24 according to the first embodiment compares the shapes of the
Fig. 5 is a flowchart showing a pump operation control procedure executed by the
In step S51, a pump operating state detection process is executed. In the first embodiment, for example, the rotation speed of the rotor shaft 15, the motor current value flowing through the motor 16, the motor voltage applied to the motor 16, the pedestal temperature used for control for preventing accumulation of products, and the like are detected. The rotational speed of the rotor shaft 15 is detected by a rotational speed sensor 18 provided in the
In step S52, a pump control process of controlling the rotation speed of the motor 16 and the base temperature to appropriate values is performed using the rotor rotation speed, the motor current, the motor voltage, the base temperature, and the like obtained in step S51.
In step S53, a pump monitoring process for monitoring the presence or absence of a pump abnormal state is executed. Details of the pump monitoring process are described with reference to fig. 6 and 7.
In the pump control process, motor rotation speed control, stator temperature control, and the like are repeated. The pump monitoring process of step S53 is executed each time various controls are ended in the pump control process of step S52, or the pump monitoring process of step S53 is executed after various controls are repeated a plurality of times. Therefore, steps S51 to S53 are repeatedly executed.
The pump monitoring process of step S53 in fig. 5 will be described in detail with reference to fig. 6 and 7. In step S1, it is determined whether or not the
If step S3 is affirmative, the routine proceeds to step S4, and the time-series data of the motor current value stored in the storage unit 25 is set as the data of the
When it is determined in step S1 that the reference waveform has been acquired, the flow proceeds to step S5.
In step S5 subsequent to step S4, the motor current value is sampled at predetermined time intervals. In step S6, it is determined whether or not a predetermined period has elapsed, and the sampling of the motor current value is continued until the determination is affirmative. The sampled motor current value is stored in the storage unit 25. If step S6 is affirmative, the routine proceeds to step S7, and the time-series data of the motor current value stored in the storage unit 25 is set as the data of the
Fig. 7 is a flowchart illustrating the pump abnormality determination process of step S8. The pump abnormality determination process is a process for detecting a pump abnormal state using the acquired
In step S11, the data of the
The pump abnormality detection processing performed by the program processing shown in fig. 5 to 7 is summarized as follows.
When a command for starting the
After the rotor shaft 15 rotates at the rated rotation speed, the process for the processing object such as a substrate is started. The influence of the deposit on the motor control is small from the start of the process until the predetermined period elapses. A waveform in which the motor current acquired within the predetermined period changes in time series is stored as a
In fig. 4, the
In the current value waveform shown in fig. 8(a), the difference between the measured
The measured
The elliptical regions C1, C2, C3, and C4 in fig. 8(a) are regions for calculating the difference between the actual measurement waveform and the reference waveform when the matching degree of the current value waveform pattern is calculated. Actually, the actual measurement waveform and the reference waveform are obtained by sampling the current value within a predetermined time range set in each region of each process at a predetermined time interval. Their difference values are calculated in a difference value calculation area. The larger the difference within the prescribed time range, the smaller the value given to the score for the calculation of the degree of coincidence. The matching degree of the waveform is determined based on the total value of the matching degree calculation scores calculated in the respective regions. The larger the sum of the scores, the higher the degree of agreement.
The pattern matching calculation is not limited to the above example, and may be performed by various other methods.
In the current value waveform shown in fig. 8(b), the difference between the measured
The operation of the pump monitoring device according to the first embodiment described above is summarized as follows.
(1) The pump monitoring apparatus is a monitoring apparatus of a
Therefore, the chance of erroneously notifying a warning can be suppressed as compared with the conventional technique in which the current value of the motor for rotationally driving the rotor of the vacuum pump is measured and a warning is issued when the amount of change in the measured value from the initial value of the motor current is equal to or greater than a predetermined value.
(2) The setting unit 24b of the pump monitoring device acquires a signal waveform of a motor current value within a predetermined time after the
With this configuration, the
Second embodiment
In the first embodiment, it is assumed that an abnormal state of the pump is monitored by comparing the reference waveform with the measured waveform for one process (for example, an etching process). In the second embodiment, the reference waveform is acquired for each of two or more processes, for example, two different kinds of etching processes, and the pump abnormality is monitored by comparing the reference waveform unique to each process with the actually measured waveform. For example, in two different etching processes, the waveforms of the motor current values in one section of the process are different, and therefore, in order to correctly perform pattern matching, the reference waveform must be changed in each process.
Fig. 9 is a diagram showing details of the pump monitoring process in step S53 in fig. 5 according to the second embodiment. The same reference numerals are given to the same portions as those in fig. 6 of the first embodiment, and the differences will be mainly described.
In step S91, the process being performed in the
If the switching of the process is not determined in step S93, the actually measured waveform is stored and saved in step S6 until the predetermined period ends. Thereafter, the actual measurement waveform is set in step S7, and pump abnormality determination is performed in step S8.
When it is determined in step S93 that the process has been switched within the predetermined period, the process returns to step S7 by skipping the setting of the actual measurement waveform of the process and the comparison between the actual measurement waveform and the reference waveform in step S8.
The identification of the process of step S91 can be performed in the following manner.
For example, in two different etching processes, one unit processing time of the process treatment is different. Referring to fig. 4, the unit processing time is an interval time from time t1 to
Alternatively, the cleaning process is performed when switching from one etching process to another. The cleaning process may also be identified to identify that a switch from one etch process to another has been made to identify a process switch.
Alternatively, the
In the pump monitoring apparatus according to the second embodiment, a process currently being processed among a plurality of processes performed in the
The pump monitoring device according to the second embodiment is summarized as follows.
(3) The setting unit 24b and the setting unit 24c of the pump monitoring apparatus set the
With this configuration, it is possible to determine a pump abnormality by comparing a reference waveform and an actual measurement waveform that are appropriately selected for each of a plurality of processes performed in the
(modification 1)
As shown in fig. 4, 8(a) and 8(b), in the first and second embodiments, pattern matching between the
That is, in the pump monitoring device according to
Therefore, compared with the case where pattern matching is performed in the entire area in one step of the same process, the abnormality determination algorithm is simplified, the cost is reduced, and the determination time can also be shortened.
(modification 2)
The pump monitoring device according to
When the motor is driven at the maximum current value, the rate of increase in load due to deposits is greater than in the case where the motor is driven at a small current value, and therefore, the pump abnormality can be monitored with high accuracy.
(modification 3)
In the pump monitoring device according to modification 3, the pump abnormality determination may be performed using the current value waveform in any two or more regions from region C1 to region C4 in fig. 8 (a).
(modification 4)
The pump abnormality determination algorithm using the average value performed by the pump monitoring device according to
(modification 5)
The pump abnormality determination may be performed by using the motor rotation speed, the control current value of the magnetic bearing control, or the like, instead of determining the pump abnormality using the motor current value. These physical quantities can be used as an index representing the pump load caused by the deposit.
(modification 6)
In the first and second embodiments and the modification, the time-series motor current value within a predetermined period after the
In the above, an increase in the pump load due to the deposition of the impurity components of the process gas on the rotor or the like has been described as an example. However, regardless of whether the cause of the increase in the pump load abnormality is caused by deposits, the device for monitoring the pump abnormality associated with the increase in the pump load based on the comparison between the reference waveform and the measured waveform as in the present invention may also be used for monitoring the pump abnormality in which the pump load increases due to other factors.
While various embodiments have been described above, the present invention is not limited to these embodiments. Other embodiments that can be conceived within the scope of the technical idea of the present invention are also included in the scope of the present invention. Further, a plurality of embodiments may be combined.
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