JP5404702B2 - Vacuum exhaust system - Google Patents

Description

  The present invention relates to a cryopump and a monitoring method thereof.

  The cryopump is a vacuum pump that traps and exhausts gas molecules by condensation or adsorption onto a cryopanel cooled to a very low temperature. The cryopump is generally used to realize a clean vacuum environment required for a semiconductor circuit manufacturing process or the like.

  For example, Patent Document 1 describes a production management system in which a plurality of production apparatuses such as sputtering apparatuses are connected to a central host computer via a LAN. Each production apparatus is provided with a cryopump. Then, an independent network different from the production apparatus network is constructed between the plurality of cryopumps and the maintenance management computer. Thereby, maintenance or management of a plurality of cryopumps is performed collectively.

JP-A-6-301617

  However, since the above-described production management system needs to newly install a maintenance management computer and to construct a new separate network, the cost of the system is increased. In addition, since the network is separate from the production apparatus network, the operation state of the cryopump is merely recorded and managed independently of the production apparatus.

  Therefore, an object of the present invention is to provide a cryopump that realizes cryopump operation state monitoring suitable for a vacuum apparatus to which a cryopump is attached, for example, using an existing cryopump control apparatus, and a monitoring method thereof. .

  A cryopump according to an aspect of the present invention is a cryopump that exhausts gas from a vacuum chamber of a vacuum apparatus that performs vacuum processing, and a refrigerator, a cryopanel cooled by the refrigerator, and the cryopanel as a target A control unit that controls the operating frequency of the refrigerator so as to control the temperature. The controller monitors the operating frequency for a first determination time when the operating frequency of the refrigerator reaches a first determination criterion, and the operation frequency corresponds to a second load corresponding to a higher load than the first determination criterion. When the determination criterion is reached, the temperature of the cryopanel is monitored for a second determination time shorter than the first determination time.

  According to this aspect, the refrigerator operating frequency is controlled so as to maintain the cryopanel at the target temperature in accordance with the load fluctuation to the cryopump due to the vacuum device operating state. The vacuum apparatus has an operation state in which a load is temporarily increased and an operation state in which a high load is continuously applied. Therefore, the operating state of the vacuum apparatus can be estimated by monitoring the fluctuation of the operating frequency quantitatively and temporally. In addition, it is possible to distinguish between a change in the operating state of the vacuum apparatus and a cryopump abnormality. Furthermore, it can monitor more accurately by using temperature monitoring together.

  The first determination time may be set longer than the baking time required for the baking process for heating the vacuum chamber and discharging the gas, and the second determination time may be set shorter than the baking time.

  The control unit calculates the first determination time from when the operating frequency reaches the first reference frequency, and continues monitoring until the operating frequency falls below a second reference frequency that is smaller than the first reference frequency. May be.

  The first reference frequency may be set to a value larger than a maximum operation frequency assumed during the vacuum processing.

  The controller may monitor the temperature of the cryopanel when the operating frequency reaches a third reference frequency that is higher than the first reference frequency.

  The cryopanel may include a first-stage cryopanel and a two-stage cryopanel cooled to a lower temperature than the first-stage cryopanel. The control unit removes any of the operating frequency of the refrigerator, the temperature of the first-stage cryopanel, and the temperature of the second-stage cryopanel when the first-stage cryopanel is controlled to the target temperature. When the state exceeding the threshold value continues for a set time or more, it may be determined that the refrigerator is abnormal.

  When the operating frequency of the refrigerator and the temperature of the first-stage cryopanel exceed a threshold value continue for the set time or more, and the temperature of the second-stage cryopanel returns within the set time Alternatively, it may be determined that a baking process is being performed in the vacuum apparatus.

  Another aspect of the present invention is a cryopump monitoring method. This method is a monitoring method of a cryopump that exhausts a vacuum device that performs vacuum processing, and when operating frequency variable control is performed to control the operating frequency of the refrigerator so as to control the cryopanel to a target temperature, When the operation frequency of the refrigerator reaches the first determination criterion, the operation frequency is monitored for a first determination time, and during the variable operation frequency control, the operation frequency corresponds to a higher load than the first determination criterion. Monitoring the temperature of the cryopanel for a second determination time shorter than the first determination time when the second determination criterion is reached.

  According to the present invention, it is possible to realize cryopump operation state monitoring suitable for a vacuum apparatus to which a cryopump is attached.

It is sectional drawing which shows typically the cryopump which concerns on one Embodiment of this invention. It is a control block diagram regarding the cryopump according to the present embodiment. It is a flowchart for demonstrating an example of the monitoring process which concerns on this embodiment. It is a flowchart for demonstrating the monitoring process which concerns on other embodiment.

  In one embodiment, the cryopump is attached to a vacuum chamber of a vacuum device and exhausts gas from the vacuum chamber. The vacuum device is a device that performs a desired vacuum process. The vacuum treatment is, for example, a surface treatment for treating the surface of an object to be processed in a vacuum environment. Examples of the vacuum apparatus include film forming apparatuses such as a sputtering apparatus, a CVD apparatus, and a vacuum deposition apparatus, and other semiconductor manufacturing apparatuses that require a vacuum environment. In a device manufacturing system including a vacuum apparatus, the vacuum apparatus is usually regarded as an upper apparatus, and the cryopump is regarded as a lower apparatus.

  Apart from the control unit of the cryopump, the vacuum apparatus is usually provided with a controller for executing and managing a desired vacuum process. The controller of the vacuum apparatus and the control unit of the cryopump may be communicably connected via an appropriate interface or network. However, in this case, it may be designed not to transmit information on the operating state of the vacuum device from the upper vacuum device controller to the lower cryopump control unit.

  In addition to vacuum processing, the vacuum apparatus may take an operating state in which a higher load is continuously applied to the cryopump than vacuum processing. As an operation state in which a high heat load is applied to the cryopump, for example, there is a baking process of a vacuum apparatus. In general, the baking process refers to a process in which a vacuum chamber of a vacuum apparatus is heated to discharge the stored gas or the like to the outside.

  When the operating frequency of the refrigerator is variably controlled so as to maintain the cryopanel at the target temperature, the operating frequency varies according to the thermal load on the cryopump. The heat load also varies depending on the operating state of the vacuum device. The operation state of the vacuum device includes an operation state in which the thermal load on the cryopump is increased in the short term (for example, vacuum processing) and an operation state in which the heat load is increased in the long term and in a larger amount (for example, baking processing). ) Therefore, the operating state of the vacuum apparatus can be estimated by monitoring the magnitude of fluctuation of the operating frequency of the refrigerator and the duration of the fluctuation together. In addition, it is possible to distinguish between a change in the operating state of the vacuum apparatus and a cryopump abnormality.

  In one embodiment, the control unit of the cryopump controls the temperature of the cryopanel so that the exhaust target volume such as a vacuum chamber is exhausted to a target vacuum level. This control unit gives an operation command to the refrigerator that is thermally connected to the cryopanel so that the actual temperature of the cryopanel follows the target temperature. The refrigerator generates cold by a heat cycle in which a working gas is sucked, expanded inside and discharged. For example, the control unit uses the frequency of the thermal cycle of the refrigerator as an operation command. In this case, a control part determines the command value of the frequency of a heat cycle, and gives it to a refrigerator so that the actual temperature of a cryopanel may track target temperature. As a result, the refrigerator is operated in accordance with the frequency command value during normal operation.

  The refrigerator includes a flow path switching mechanism that periodically switches the flow path of the working gas in order to periodically suck and discharge the working gas. The flow path switching mechanism includes, for example, a valve unit and a drive unit that drives the valve unit. The valve unit is a rotary valve, for example, and the drive unit is a motor for rotating the rotary valve. The motor may be an AC motor or a DC motor, for example. The flow path switching mechanism may be a direct acting mechanism driven by a linear motor.

  The control unit may determine a command value for the motor rotation number instead of determining a command value for the heat cycle frequency. In the case of a so-called direct drive system in which the rotational output of the motor is directly transmitted to the valve unit, the motor rotational speed and the thermal cycle frequency coincide. When the motor is connected to the valve portion via a power transmission mechanism including a reduction gear or the like, the motor rotation speed and the thermal cycle frequency have a certain relationship. In this case, the control unit determines the motor rotation speed corresponding to the heat cycle frequency necessary for causing the cryopanel temperature to follow the target temperature as a command value, and supplies the command value to the refrigerator. In addition, when the refrigerator is provided with a direct-acting flow path switching mechanism including a linear motor, the controller reciprocates the linear motor corresponding to the thermal cycle frequency necessary for causing the cryopanel temperature to follow the target temperature. The frequency of motion is determined as a command value and given to the refrigerator. In the following, for the sake of convenience, the rotational speed of the rotary motor and the reciprocating frequency of the linear motor may be collectively referred to as the motor operating frequency.

  In one embodiment according to the present invention, the control unit of the cryopump monitors the operation state of the cryopump under a plurality of monitoring conditions having different time widths. The control unit, for example, a first monitoring condition for monitoring the driving state with a short-term time width, a second monitoring condition for monitoring the driving state with a medium-term time width, and a first monitoring condition for monitoring the driving state with a long-term time width. You may monitor a cryopump using 3 monitoring conditions together. Here, the monitoring condition means that, for example, the state where the temperature of the cryopanel exceeds the reference and the temperature is increased continues for a predetermined time or more. In the short-term monitoring condition, it may be determined that the monitoring condition is satisfied when the reference is reached. As the time width of the monitoring condition becomes longer, restrictions on the operating state (for example, temperature reference) may be tightened. For example, the determination reference temperature in the second monitoring condition may be set to a lower temperature than the determination reference temperature in the first monitoring condition, and the determination reference temperature in the third monitoring condition may be set to be lower than the second monitoring condition. By setting the monitoring conditions in stages as described above, it is possible to accurately detect the deviation of the cryopump operation state from the standard state.

  The cryopump may include a plurality of cryopanels cooled to different temperatures, for example, a low-temperature cryopanel and a high-temperature cryopanel. The control unit may control one of the low-temperature cryopanel and the high-temperature cryopanel to the target temperature, and monitor the state of the other cryopanel under the above-described monitoring conditions.

  Instead of directly measuring the cryopanel temperature, for example, when a heater for adjusting the cryopanel temperature is attached to the cryopanel, the control command value (for example, current) to the heater remains smaller than the reference. It may be a monitoring condition. Or it replaces with cryopanel temperature and it is good also as monitoring conditions that the state where the operating frequency of a refrigerator exceeds a standard continues.

  The control unit may store that at least one of the plurality of monitoring conditions is satisfied, or may output a warning at the time of establishment. This is because when the monitoring condition is satisfied, the performance of the cryopump may be deteriorated. Therefore, the control unit may diagnose the performance deterioration of the cryopump when at least one of the plurality of monitoring conditions is satisfied, and recommend maintenance of the cryopump.

  Hereinafter, the best mode for carrying out the present invention will be described in more detail with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a cryopump 10 according to an embodiment of the present invention.

The cryopump 10 is attached to a vacuum chamber 80 such as an ion implantation apparatus or a sputtering apparatus, and is used to increase the degree of vacuum inside the vacuum chamber 80 to a level required for a desired process. For example, a high degree of vacuum of about 10 ⁻⁵ Pa to 10 ⁻⁸ Pa is realized.

The cryopump 10 includes: a first cryopanel that is cooled to a first cooling temperature level; and a second cryopanel that is cooled to a second cooling temperature level lower than the first cooling temperature level. Prepare. In the first cryopanel, a gas having a low vapor pressure at the first cooling temperature level is captured by condensation and exhausted. For example, a gas having a vapor pressure lower than a reference vapor pressure (for example, 10 ⁻⁸ Pa) is exhausted. In the second cryopanel, gas having a low vapor pressure at the second cooling temperature level is captured by condensation and exhausted. An adsorption region is formed on the surface of the second cryopanel in order to capture non-condensable gas that does not condense even at the second temperature level due to high vapor pressure. The adsorption region is formed, for example, by providing an adsorbent on the panel surface. The non-condensable gas is adsorbed in the adsorption region cooled to the second temperature level and exhausted.

  A cryopump 10 shown in FIG. 1 includes a refrigerator 12, a panel structure 14, and a heat shield 16. The panel structure 14 includes a plurality of cryopanels, and these panels are cooled by the refrigerator 12. A cryogenic surface for trapping and exhausting gas by condensation or adsorption is formed on the panel surface. Generally, an adsorbent such as activated carbon for adsorbing gas is provided on the front surface (for example, the back surface) of the cryopanel.

  The cryopump 10 is a so-called vertical cryopump. The vertical cryopump is a cryopump in which the refrigerator 12 is inserted along the axial direction of the heat shield 16. The present invention can also be applied to a so-called horizontal cryopump. The horizontal cryopump is a cryopump in which the second cooling stage of the refrigerator is inserted and arranged in a direction (usually an orthogonal direction) intersecting the axial direction of the heat shield 16.

  The refrigerator 12 is a Gifford McMahon refrigerator (so-called GM refrigerator). The refrigerator 12 is a two-stage refrigerator, and includes a first-stage cylinder 18, a second-stage cylinder 20, a first cooling stage 22, a second cooling stage 24, and a refrigerator motor 26. The first-stage cylinder 18 and the second-stage cylinder 20 are connected in series, and a first-stage displacer and a second-stage displacer (not shown) that are connected to each other are incorporated therein. A regenerator material is incorporated inside the first stage displacer and the second stage displacer. The refrigerator 12 may be a refrigerator other than the two-stage GM refrigerator, for example, a single-stage GM refrigerator or a pulse tube refrigerator.

  A refrigerator motor 26 is provided at one end of the first stage cylinder 18. The refrigerator motor 26 is provided inside a motor housing 27 formed at the end of the first stage cylinder 18. The refrigerator motor 26 is provided in the first stage displacer and the second stage displacer so that the first stage displacer and the second stage displacer can reciprocate inside the first stage cylinder 18 and the second stage cylinder 20, respectively. Connected. The refrigerator motor 26 is connected to the movable valve (not shown) provided inside the motor housing 27 so as to be able to rotate forward and reverse.

  The first cooling stage 22 is provided at an end portion of the first stage cylinder 18 on the second stage cylinder 20 side, that is, a connecting portion between the first stage cylinder 18 and the second stage cylinder 20. The second cooling stage 24 is provided at the end of the second stage cylinder 20. The first cooling stage 22 and the second cooling stage 24 are fixed to the first stage cylinder 18 and the second stage cylinder 20 by brazing, for example.

  The compressor 40 is connected to the refrigerator 12 via a high pressure pipe 42 and a low pressure pipe 44. The high pressure pipe 42 and the low pressure pipe 44 are provided with a first pressure sensor 43 and a second pressure sensor 45 for measuring the pressure of the working gas, respectively. Instead of providing a pressure sensor for each of the high-pressure pipe 42 and the low-pressure pipe 44, a flow path that connects the high-pressure pipe 42 and the low-pressure pipe 44 is provided, and a differential pressure for measuring the differential pressure between the high-pressure pipe 42 and the low-pressure pipe 44. A sensor may be provided in the communication channel.

  The refrigerator 12 expands a high-pressure working gas (for example, helium) supplied from the compressor 40 to generate cold in the first cooling stage 22 and the second cooling stage 24. The compressor 40 collects the working gas expanded in the refrigerator 12, pressurizes it again, and supplies it to the refrigerator 12.

  Specifically, first, high-pressure working gas is supplied from the compressor 40 to the refrigerator 12 through the high-pressure pipe 42. At this time, the refrigerator motor 26 drives the movable valve in the motor housing 27 so that the high-pressure pipe 42 and the internal space of the refrigerator 12 communicate with each other. When the internal space of the refrigerator 12 is filled with the high-pressure working gas, the movable valve is switched by the refrigerator motor 26 and the internal space of the refrigerator 12 is communicated with the low-pressure pipe 44. As a result, the working gas expands and is recovered into the compressor 40. In synchronization with the operation of the movable valve, the first stage displacer and the second stage displacer reciprocate inside the first stage cylinder 18 and the second stage cylinder 20, respectively. The refrigerator 12 generates cold in the first cooling stage 22 and the second cooling stage 24 by repeating such a heat cycle. Further, in the compressor 40, a compression cycle in which the working gas discharged from the refrigerator 12 is compressed to a high pressure and sent to the refrigerator 12 is repeated.

  The second cooling stage 24 is cooled to a lower temperature than the first cooling stage 22. The second cooling stage 24 is cooled to about 10K to 20K, for example, and the first cooling stage 22 is cooled to about 80K to 100K, for example. A first temperature sensor 23 for measuring the temperature of the first cooling stage 22 is attached to the first cooling stage 22, and a second temperature stage for measuring the temperature of the second cooling stage 24 is attached to the second cooling stage 24. A two-temperature sensor 25 is attached.

  The heat shield 16 is fixed to the first cooling stage 22 of the refrigerator 12 in a thermally connected state, and the panel structure 14 is thermally connected to the second cooling stage 24 of the refrigerator 12. It is fixed. For this reason, the heat shield 16 is cooled to the same temperature as the first cooling stage 22, and the panel structure 14 is cooled to the same temperature as the second cooling stage 24.

  The heat shield 16 is provided to protect the panel structure 14 and the second cooling stage 24 from ambient radiant heat. The heat shield 16 is formed in a cylindrical shape having an opening 31 at one end. The opening 31 is defined by the inner surface of the end of the cylindrical side surface of the heat shield 16.

  On the other hand, a closing portion 28 is formed at the other end of the heat shield 16 opposite to the opening portion 31, that is, at the pump bottom portion side. The closing portion 28 is formed by a flange portion extending radially inward at the end portion on the pump bottom side of the cylindrical side surface of the heat shield 16. Since the cryopump 10 shown in FIG. 1 is a vertical cryopump, the flange portion is attached to the first cooling stage 22 of the refrigerator 12. Thereby, a cylindrical internal space 30 is formed inside the heat shield 16. The refrigerator 12 projects into the internal space 30 along the central axis of the heat shield 16, and the second cooling stage 24 is inserted into the internal space 30.

  In the case of a horizontal cryopump, the closing portion 28 is normally completely closed. The refrigerator 12 is disposed so as to protrude into the internal space 30 along a direction orthogonal to the central axis of the heat shield 16 from the opening for attaching the refrigerator formed on the side surface of the heat shield 16. The first cooling stage 22 of the refrigerator 12 is attached to the opening for attaching the refrigerator of the heat shield 16, and the second cooling stage 24 of the refrigerator 12 is arranged in the internal space 30. The panel structure 14 is attached to the second cooling stage 24. Therefore, the panel structure 14 is disposed in the internal space 30 of the heat shield 16. The panel structure 14 may be attached to the second cooling stage 24 via a panel attachment member having an appropriate shape.

  The shape of the heat shield 16 is not limited to a cylindrical shape, and may be a cylindrical shape having any cross section such as a rectangular tube shape or an elliptical cylinder shape. Typically, the shape of the heat shield 16 is similar to the shape of the inner surface of the pump case 34. Further, the heat shield 16 may not be configured as an integral cylinder as illustrated, and may be configured so as to form a cylindrical shape as a whole by a plurality of parts. The plurality of parts may be arranged with a gap therebetween.

  A baffle 32 is provided in the opening 31 of the heat shield 16. The baffle 32 is provided at a distance from the panel structure 14 in the central axis direction of the heat shield 16. The baffle 32 is attached to the end of the heat shield 16 on the opening 31 side, and is cooled to a temperature similar to that of the heat shield 16. The baffle 32 may be formed concentrically, for example, when viewed from the vacuum chamber 80 side, or may be formed in other shapes such as a lattice shape. A gate valve (not shown) is provided between the baffle 32 and the vacuum chamber 80. This gate valve is closed when, for example, the cryopump 10 is regenerated, and is opened when the vacuum chamber 80 is evacuated by the cryopump 10.

  The heat shield 16, the baffle 32, the panel structure 14, and the first cooling stage 22 and the second cooling stage 24 of the refrigerator 12 are accommodated in the pump case 34. The pump case 34 is formed by connecting two cylinders having different diameters in series. The large-diameter cylindrical side end of the pump case 34 is opened, and a flange portion 36 for connection to the vacuum chamber 80 is formed extending outward in the radial direction. The small cylindrical end of the pump case 34 is fixed to the motor housing 27 of the refrigerator 12. The cryopump 10 is airtightly fixed to the exhaust opening of the vacuum chamber 80 via the flange portion 36 of the pump case 34, and an airtight space integrated with the internal space of the vacuum chamber 80 is formed.

  Both the pump case 34 and the heat shield 16 are formed in a cylindrical shape and are arranged coaxially. Since the inner diameter of the pump case 34 is slightly larger than the outer diameter of the heat shield 16, the heat shield 16 is disposed with a slight gap between the inner surface of the pump case 34.

  FIG. 2 is a control block diagram relating to the cryopump 10 according to the present embodiment. Along with the cryopump 10, a cryopump controller (hereinafter also referred to as a CP controller) 100 for controlling the cryopump 10 and the compressor 40 is provided. The CP controller 100 includes a CPU that executes various arithmetic processes, a ROM that stores various control programs, a RAM that is used as a work area for data storage and program execution, an input / output interface, a memory, and the like. The CP controller 100 may be configured integrally with the cryopump 10 or may be configured separately from the cryopump 10 so as to be communicable with each other.

  1 and 2 show an evacuation system including one cryopump 10 and one compressor 40. In this embodiment, a vacuum including a plurality of cryopumps 10 and compressors 40 is provided. An exhaust system may be configured. Therefore, the CP controller 100 may be configured to connect a plurality of cryopumps 10 and compressors 40.

  A first temperature sensor 23 that measures the temperature of the first cooling stage 22 of the refrigerator 12 and a second temperature sensor 25 that measures the temperature of the second cooling stage 24 of the refrigerator 12 are connected to the CP controller 100. Yes. The first temperature sensor 23 periodically measures the temperature of the first cooling stage 22 and outputs a signal indicating the measured temperature to the CP controller 100. The second temperature sensor 25 periodically measures the temperature of the second cooling stage 24 and outputs a signal indicating the measured temperature to the CP controller 100. The measured values of the first temperature sensor 23 and the second temperature sensor 25 are input to the CP controller 100 every predetermined time and stored and held in a predetermined storage area of the CP controller 100.

  Further, the CP controller 100 includes a first pressure sensor 43 that measures the working gas pressure on the discharge side of the compressor 40, that is, the high pressure side, and a second pressure that measures the working gas pressure on the suction side, that is, the low pressure side of the compressor 40. A sensor 45 is connected. For example, the first pressure sensor 43 periodically measures the pressure in the high-pressure pipe 42 and outputs a signal indicating the measured pressure to the CP controller 100. For example, the second pressure sensor 45 periodically measures the pressure in the low-pressure pipe 44 and outputs a signal indicating the measured pressure to the CP controller 100. The measured values of the first pressure sensor 43 and the second pressure sensor 45 are input to the CP controller 100 every predetermined time, and are stored and held in a predetermined storage area of the CP controller 100.

  The CP controller 100 is communicably connected to the refrigerator frequency converter 50. Further, the refrigerator frequency converter 50 and the refrigerator motor 26 are communicably connected. The CP controller 100 transmits a control command to the refrigerator frequency converter 50. The refrigerator frequency converter 50 includes a refrigerator inverter 52. The refrigerator frequency converter 50 is supplied with electric power having a specified voltage and frequency from the refrigerator power supply 54, adjusts the voltage and frequency based on a control command transmitted from the CP controller 100, and operates the refrigerator motor 26. To supply.

  The CP controller 100 is communicably connected to the compressor frequency converter 56. Further, the compressor frequency converter 56 and the compressor motor 60 are communicably connected. The CP controller 100 transmits a control command to the compressor frequency converter 56. The compressor frequency converter 56 includes a compressor inverter 58. The compressor frequency converter 56 is supplied with electric power of a predetermined voltage and frequency from the compressor power supply 62, adjusts the voltage and frequency based on a control command transmitted from the CP controller 100, and compresses the motor 60. To supply. In the embodiment shown in FIG. 2, the refrigerator power source 54 and the compressor power source 62 are individually provided in the refrigerator 12 and the compressor 40, respectively. A common power supply may be provided.

  The CP controller 100 controls the refrigerator 12 based on the temperature of the cryopanel. The CP controller 100 gives an operation command to the refrigerator 12 so that the actual temperature of the cryopanel follows the target temperature. For example, the CP controller 100 controls the operating frequency of the refrigerator motor 26 by feedback control so as to minimize the deviation between the target temperature of the first stage cryopanel and the temperature measured by the first temperature sensor 23. The target temperature of the first-stage cryopanel is determined as a specification according to the process performed in the vacuum chamber 80, for example. In this case, the second cooling stage 24 and the panel structure 14 of the refrigerator 12 are cooled to a temperature determined by the specifications of the refrigerator 12 and the external heat load. The CP controller 100 determines the operating frequency (for example, the number of revolutions of the motor) of the refrigerator motor 26 so that the actual temperature of the first-stage cryopanel matches the target temperature, for example, and operates the motor for the inverter 52 for the refrigerator. Outputs the frequency command value. The CP controller 100 can also control the operating frequency of the refrigerator motor 26 so that the actual temperature of the second stage cryopanel matches the target temperature.

  Thereby, when the measured temperature of the first temperature sensor 23 is higher than the target temperature, the CP controller 100 instructs the refrigerator frequency converter 50 to increase the operating frequency of the refrigerator motor 26. Is output. The frequency of the heat cycle in the refrigerator 12 is increased in conjunction with the increase in the motor operating frequency, and the first cooling stage 22 of the refrigerator 12 is cooled toward the target temperature. Conversely, when the temperature measured by the first temperature sensor 23 is lower than the target temperature, the operating frequency of the refrigerator motor 26 is decreased, and the first cooling stage 22 of the refrigerator 12 increases toward the target temperature. Be warmed.

  Normally, the target temperature of the first cooling stage 22 is set to a constant value. Therefore, the CP controller 100 outputs a command value so as to increase the operating frequency of the refrigerator motor 26 when the thermal load on the cryopump 10 increases, and when the thermal load on the cryopump 10 decreases. A command value is output so as to reduce the operating frequency of the refrigerator motor 26. Note that the target temperature may be appropriately changed. For example, the target temperature of the cryopanel may be sequentially set so as to realize the target atmospheric pressure in the exhaust target volume.

  In a typical cryopump, the frequency of the thermal cycle is always constant. It is set to operate at a relatively high frequency so as to enable rapid cooling from normal temperature to the pump operating temperature. When the external heat load is small, the temperature of the cryopanel is adjusted by heating with a heater. Therefore, power consumption increases. On the other hand, in this embodiment, since the thermal cycle frequency is controlled according to the thermal load on the cryopump 10, a cryopump excellent in energy saving can be realized. In addition, the fact that there is no need to provide a heater also contributes to reduction of power consumption.

  Further, the CP controller 100 controls the frequency of the compression cycle executed by the compressor 40 so as to maintain the differential pressure between the inlets and outlets of the compressor 40 (hereinafter also referred to as the compressor differential pressure) at the target pressure. . For example, the CP controller 100 controls the compression cycle frequency by feedback control so that the differential pressure between the inlet and outlet of the compressor 40 is a constant value. Specifically, the CP controller 100 obtains the compressor differential pressure from the measured values of the first pressure sensor 43 and the second pressure sensor 45. The CP controller 100 determines the operating frequency (for example, the number of rotations of the motor) of the compressor motor 60 so that the compressor differential pressure matches the target value, and sends a command value for the motor operating frequency to the compressor frequency converter 56. Is output.

  By such differential pressure constant control, further reduction of power consumption is realized. When the thermal load on the cryopump 10 and the refrigerator 12 is small, the thermal cycle frequency in the refrigerator 12 is reduced by the above-described cryopanel temperature control. Then, since the working gas flow rate required in the refrigerator 12 becomes small, the pressure difference between the inlet and outlet of the compressor 40 tends to increase. However, in this embodiment, the operation frequency of the compressor motor 60 is controlled and the compression cycle frequency is adjusted so that the compressor differential pressure is constant. Therefore, in this case, the operating frequency of the compressor motor 60 is reduced. Therefore, power consumption can be reduced compared to a case where the compression cycle is always constant as in a typical cryopump.

  On the other hand, when the thermal load on the cryopump 10 increases, the operating frequency and the compression cycle frequency of the compressor motor 60 are also increased so as to make the compressor differential pressure constant. For this reason, since the working gas flow rate to the refrigerator 12 can be sufficiently ensured, the deviation of the cryopanel temperature from the target temperature due to an increase in thermal load can be minimized.

  The operation of the cryopump 10 having the above configuration will be described below. When the cryopump 10 is operated, first, the vacuum chamber 80 is roughly evacuated to about 1 Pa using another appropriate roughing pump before the operation. Thereafter, the cryopump 10 is operated. The first cooling stage 22 and the second cooling stage 24 are cooled by driving the refrigerator 12, and the heat shield 16, the baffle 32, and the panel structure 14 that are thermally connected thereto are also cooled.

  The cooled baffle 32 cools gas molecules flying from the vacuum chamber 80 toward the inside of the cryopump 10, and exhausts gas (for example, moisture) whose vapor pressure is sufficiently low at the cooling temperature to condense on the surface. To do. A gas whose vapor pressure does not become sufficiently low at the cooling temperature of the baffle 32 passes through the baffle 32 and enters the heat shield 16. Of the gas molecules that have entered, a gas whose vapor pressure is sufficiently low at the cooling temperature of the panel structure 14 (for example, argon) is condensed on the surface of the panel structure 14 and exhausted. A gas (for example, hydrogen) whose vapor pressure does not become sufficiently low even at the cooling temperature is adsorbed and exhausted by an adsorbent that is bonded to the surface of the panel structure 14 and cooled. In this way, the cryopump 10 can reach the desired degree of vacuum inside the vacuum chamber 80.

  In one embodiment, a cryopanel temperature limit is set in the controller of the vacuum device to display a warning when the cryopump cryopanel temperature is abnormally elevated or to stop the vacuum process. It may be. The panel limit temperature set in the vacuum apparatus is, for example, a temperature at which it is assumed that an abnormality has occurred in the cryopump. Therefore, as long as this panel limit temperature is not reached, the vacuum apparatus can be regarded as the cryopump operating normally.

  The control device of the vacuum device receives panel temperature input from the cryopump and determines whether or not the input temperature exceeds the limit temperature. If the limit temperature is exceeded, a warning is output or the running vacuum process is stopped. When the vacuum process is stopped along with the temperature rise to the panel limit temperature, the downtime of the vacuum apparatus suddenly occurs. Such sudden occurrence of downtime is not preferable because it will interfere with the scheduled process execution schedule. Therefore, it is preferable to mount a monitoring function or a self-diagnosis function on the cryopump to monitor the operation state of the cryopump.

  In one embodiment, the controller of the cryopump sets the temperature of the low-temperature cryopanel that is cooled in conjunction with the high-temperature cryopanel during the temperature control that controls the high-temperature cryopanel to the target temperature. It may be determined whether or not the low temperature cryopanel upper limit temperature is approached. Specifically, for example, it may be determined whether or not the temperature of the cryopanel is raised above a warning temperature set lower than the upper limit temperature of the cryopanel set in the vacuum apparatus. The control unit may output a warning when the cryopanel is heated to a warning temperature or higher, and may display the warning on the accompanying display unit.

  In this way, it is possible to detect in advance in the cryopump that the cryopanel actual temperature may reach the cryopanel upper limit temperature setting value in the vacuum apparatus. If it does so, it will become possible to cope appropriately by the next maintenance, for example. By monitoring the cryopump under monitoring conditions adapted to the settings of the vacuum device in this way, it is possible to minimize the sudden occurrence of downtime of the vacuum device.

  The control unit of the cryopump is a low-temperature cryopanel from a temperature range in which vacuum processing is guaranteed to be normally performed during temperature control of the high-temperature cryopanel (hereinafter also referred to as “vacuum process guaranteed temperature range”). It may be determined whether or not the temperature continuously deviates. For example, it may be determined whether or not the temperature of the low-temperature cryopanel is continuously increased for a set time or longer in the temperature range set with the above-described warning temperature as an upper limit. Therefore, the warning temperature may be set higher than the vacuum process guarantee temperature range.

  Whether or not the vacuum process is normally performed does not depend only on the cryopanel temperature, but depends on various parameters such as chamber pressure, chamber temperature, process gas flow rate, discharge current, and film forming material. . Rather, the cryopanel temperature may not have a major impact on the process compared to other factors. For this reason, even if the cryopanel temperature deviates from the process-guaranteed temperature range, it cannot always be said that an abnormality occurs in the process immediately. However, if the cryopanel temperature continuously deviates from the process guarantee temperature range, there is an undeniable possibility that some degree of influence will occur. By monitoring the cryopump under monitoring conditions adapted to the vacuum process in which the cryopump operates, it is possible to minimize the possibility that the cryopump adversely affects the vacuum process.

  Further, the control unit of the cryopump may determine whether or not the state where the low temperature cryopanel temperature has deviated from the low temperature cryopanel minimum temperature has continued for a long time during the temperature control of the high temperature cryopanel. For example, the control unit determines whether or not the state in which the low temperature cryopanel temperature during the exhaust operation has deviated from the lowest temperature of the low temperature cryopanel measured at the beginning of operation of the cryopump has continued for a predetermined duration or more. Also good. The reference temperature for determining whether or not the low-temperature cryopanel temperature during the exhaust operation has deviated from the lowest temperature at the beginning of operation may be set in a vacuum process guarantee temperature zone.

  It is normal that the low-temperature cryopanel temperature is within the vacuum process guaranteed temperature range. However, the minimum reached temperature of the cryopanel varies to some extent due to individual differences of cryopumps. As the cumulative operation time of the cryopump becomes longer, the minimum temperature reached tends to increase more slowly than at the beginning of operation. If the minimum temperature at the beginning of operation is low, it is preferable because the cryopanel temperature is expected to remain in the vacuum process guarantee temperature range for a long time. However, even if the low temperature cryopanel temperature is within the normal range, the aging of the cryopump may have progressed when the deviation from the initial minimum temperature has increased. The risk of failure increases with the progress of aging. By monitoring the deviation of the low temperature cryopanel temperature from the initial minimum operating temperature, it is possible to prompt the operator to check the state of the cryopump before adverse effects on the vacuum process become apparent.

  Further, the control unit of the cryopump may determine whether or not the state where the operation frequency of the refrigerator exceeds the reference is continued during the temperature control of the high-temperature cryopanel. For example, the control unit may determine whether or not a state exceeding the operation frequency serving as a determination criterion has continued for a determination time or longer. The determination time may be set longer than the time required for the baking process of the vacuum device. In this way, it is possible to discriminate between an increase in the refrigerator operating frequency due to the baking process in the vacuum device and a continuous increase in the operating frequency due to the deterioration in performance of the cryopump over time.

  In this case, the determination reference frequency may be larger than the maximum operating frequency assumed during the vacuum processing. Alternatively, the determination reference frequency may be higher than the maximum operation frequency in the no-load operation of the cryopump. The no-load operation refers to, for example, an exhaust operation that is performed from a predetermined initial pressure to a desired vacuum degree in a state where continuous gas inflow to the cryopump is stopped. Moreover, the determination reference frequency may be smaller than the upper limit operating frequency of the refrigerator. Further, the monitoring start operation frequency and the monitoring release operation frequency may be different. For example, the monitoring start operation frequency may be set to a value larger than the monitoring release operation frequency. Both the monitoring start operation frequency and the monitoring cancellation operation frequency may be larger than the maximum operation frequency assumed during the vacuum processing and smaller than the upper limit operation frequency of the refrigerator.

  Further, the control unit of the cryopump may monitor the high temperature cryopanel temperature when the operation frequency of the refrigerator approaches or reaches the upper limit value during the temperature control of the high temperature cryopanel. This upper limit value may be the maximum value of the operating frequency range allowed for the refrigerator. For example, the control unit may determine whether or not the high-temperature cryopanel temperature continues to deviate from the target temperature after the operating frequency reaches the upper limit value. At this time, the control unit may determine whether or not the state in which the high-temperature cryopanel temperature has risen above the threshold temperature higher than the target temperature has continued for a determination time or longer. The determination time may be set shorter than the time required for the baking process of the vacuum device. The threshold temperature may be lower than the upper limit temperature set in the vacuum apparatus, or may be included in the vacuum process guarantee temperature zone for the high-temperature cryopanel. The fact that the operating frequency reaches near the upper limit and the cryopanel temperature deviates from the target temperature is considered that the refrigeration capacity of the refrigerator does not catch up with the external heat load. Since it can be considered that the performance of the cryopump deteriorates with time, it is preferable to detect by monitoring.

  FIG. 3 is a flowchart for explaining an example of the monitoring process according to the present embodiment. The process shown in FIG. 3 is repeatedly executed by the CP controller 100 at a predetermined cycle during operation of the cryopump 10. In short, the CP controller 100 outputs a warning when any one of the first to sixth monitoring conditions is satisfied while the monitoring start condition is satisfied. In the processing shown in FIG. 3, the first to sixth monitoring conditions are sequentially determined in series. However, the determination order may be arbitrarily changed, and the monitoring conditions may be determined in parallel. Any one of the first to sixth monitoring conditions may be omitted.

  First, the CP controller 100 determines whether or not a monitoring start condition is satisfied (S10). Here, the monitoring start condition is that the operation mode of the cryopump 10 is under T1 temperature control. When the cryopump 10 is exhausting the vacuum chamber 80, the T1 temperature control mode is normally set. As described above, the T1 temperature control is to control the refrigerator 12 to control the temperature T1 of the first stage cryopanel (that is, the heat shield 16) to the first stage target temperature. If it is determined that the monitoring start condition is not satisfied (N in S10), the CP controller 100 ends the process without monitoring the cryopump operation state. Therefore, for example, when the cryopump 10 is in a stopped state or when the cryopump 10 is in the regeneration operation, the CP controller 100 does not perform the monitoring process of the cryopump 10.

  When the operation of the cryopump 10 is started, the cryopump 10 is first operated in a cool-down process, and then shifts from the cool-down process to an exhaust operation. In the cool-down process, it is preferable to cool the cryopanel rapidly. Therefore, the CP controller 100 may execute T2 temperature control in the cool-down process, and switch to T1 temperature control when the second-stage cryopanel is cooled to the vicinity of the second-stage target temperature. The T2 temperature control is control for cooling the second stage cryopanel (that is, the panel structure 14) to the second stage target temperature. At this time, the first-stage cryopanel may be cooled to a temperature lower than the first-stage target temperature when switching to T1 temperature control. Therefore, the CP controller 100 may set the monitoring start condition that T1 temperature control is being performed and a predetermined waiting time has elapsed since switching to T1 temperature control. For example, the waiting time may be set to a time required for the first stage cryopanel temperature to stabilize in the vicinity of the first stage target temperature. Hereinafter, a state in which this waiting time has elapsed and T1 temperature control is being performed may be referred to as a “T1 stable state”.

  When it is determined that the monitoring start condition is satisfied (Y in S10), the CP controller 100 determines whether or not the first monitoring condition is satisfied (S12). The first monitoring condition is that the second-stage cryopanel temperature has risen to a warning temperature. The warning temperature is determined in conjunction with the abnormality determination temperature set in the vacuum apparatus to which the cryopump 10 is attached. The warning temperature is set to a low temperature so that an appropriate margin is provided for the abnormality determination temperature in the vacuum apparatus. For example, when the abnormality determination temperature in the vacuum apparatus is 20K, the warning temperature is set to 18K. When it is determined that the first monitoring condition is satisfied (Y in S12), the CP controller 100 outputs a warning (S24). In this way, the CP controller 100 can sense the approach to the upper limit temperature before the cryopanel temperature rises to the cryopanel upper limit temperature in the vacuum apparatus.

  When it is determined that the first monitoring condition is not satisfied (N in S12), the CP controller 100 determines whether or not the second monitoring condition is satisfied (S14). When it is determined that the second monitoring condition is satisfied (Y in S14), the CP controller 100 outputs a warning (S24).

  The second monitoring condition is that the temperature of the second-stage cryopanel is continuously raised to a temperature range requiring attention for a set time or more. The CP controller 100 starts timing when the second-stage cryopanel temperature is newly raised to the temperature range requiring attention in the current monitoring process. The CP controller 100 determines whether or not the second-stage cryopanel temperature remains in the temperature range requiring attention in the subsequent monitoring processing, and if it remains, determines whether or not the elapsed time exceeds the set time. To do. When the set time is exceeded, the CP controller 100 determines that the second monitoring condition is satisfied. When the second-stage cryopanel temperature returns to a lower temperature than the cautionary temperature range in the subsequent monitoring process, the elapsed time count is reset, and it is determined that the second monitoring condition is not satisfied.

  The set time is set to about several tens of minutes to several hours, for example. The temperature range requiring attention is a temperature range in which the warning temperature is the upper limit and the warning temperature is the lower limit. The caution temperature is set, for example, to be equal to or higher than the upper limit value of the process guarantee temperature range in which the vacuum process is guaranteed to be performed normally. The caution temperature is, for example, 12K to 15K. It should be noted that an abnormality does not always occur immediately when the cryopanel temperature becomes higher than the process guarantee temperature range.

  Here, the caution temperature may be included in a performance guarantee temperature range in which the exhaust performance of the cryopump 10 is guaranteed. That is, the cryopump 10 can provide the exhaust performance defined in the specification even when the temperature of the second stage cryopanel is raised to the caution temperature. By setting the caution temperature in conformity with the vacuum process as described above, appropriate maintenance can be promoted even when the cryopump 10 itself is in a normal operation state. As a result, the possibility that the cryopump adversely affects the vacuum process can be minimized.

  When it is determined that the second monitoring condition is not satisfied (N in S14), the CP controller 100 determines whether the third monitoring condition is satisfied (S16). If it is determined that the third monitoring condition is satisfied (Y in S16), the CP controller 100 outputs a warning (S24).

  The third monitoring condition is that a state in which the increment of the latest second stage cryopanel minimum reached temperature relative to the second stage cryopanel minimum reached temperature at the beginning of operation of the cryopump 10 exceeds the temporal deterioration determination threshold value for a long time. is there. The CP controller 100 stores in advance a minimum reached temperature at the beginning of operation (hereinafter also referred to as “initial minimum reached temperature”). The CP controller 100 measures the second-stage cryopanel temperature a plurality of times when the operation frequency of the refrigerator 12 is smaller than the reference value in the T1 stable state at the beginning of operation of the cryopump 10, and the lowest temperature is the lowest attained temperature. Remember as. It should be noted that immediately after the cryopump 10 is installed in the vacuum apparatus and started to operate (for example, about one week), the minimum reached temperature may not be measured, and thereafter the measurement may be performed for a certain period (for example, about one week).

  When the operating frequency of the refrigerator 12 is high, the external thermal load may be in a large state, so the cryopanel temperature is expected not to be so low. Therefore, in order to obtain the true minimum temperature, it is preferable to measure when the operating frequency of the refrigerator 12 is smaller than the reference value. This operating frequency reference value may be the maximum operating frequency assumed during exhaust operation (or no-load operation) during the vacuum process, or may be a value obtained by adding a margin to the maximum operating frequency. In other words, the minimum reached temperature is not measured when the baking process is being performed in the vacuum apparatus. Since the vacuum apparatus is heated during the baking process, the operating frequency of the refrigerator tends to increase. Here, the baking process may include not only the process of heating the vacuum chamber and discharging the occluded gas and the like, but also so-called idle baking for maintaining the vacuum apparatus in a warm air state.

  Further, the CP controller 100 measures the minimum temperature reached during the exhaust operation under the same conditions as the measurement conditions of the initial minimum temperature. That is, when the operating frequency of the refrigerator 12 is lower than the reference value in the T1 stable state, the second stage cryopanel temperature is measured and stored. In the current monitoring process, the CP controller 100 starts timing when the increment of the measured minimum reached temperature with respect to the initial minimum reached temperature exceeds the temporal deterioration determination threshold. The CP controller 100 determines whether or not the latest increase in the minimum measured temperature has exceeded the time degradation determination threshold in the monitoring process after the next time, and if so, the elapsed time is set as the time degradation determination time. It is determined whether it has been exceeded. If the determination time is exceeded, the CP controller 100 determines that the third monitoring condition is satisfied. When the increase in the lowest measured temperature reaches a value below the determination threshold in the subsequent monitoring process, the elapsed time count is reset, and it is determined that the third monitoring condition is not satisfied.

  Here, the temporal degradation determination temperature obtained by adding the temporal degradation determination threshold to the initial minimum reached temperature may be included in the vacuum process guarantee temperature range, or the performance guarantee in which the exhaust performance of the cryopump 10 is guaranteed. It may be included in the temperature range. In other words, even if the latest minimum temperature that has reached the second stage cryopanel increases to the aging deterioration determination temperature, the vacuum process is not affected by the cryopump 10 at that time, and the cryopump 10 Exhaust performance can be provided. The temporal deterioration determination threshold value may be appropriately set empirically or experimentally, and may be 2K to 5K, for example.

  Individual minimum for each cryopump 10 is reflected in the initial minimum temperature. This is because each cryopump 10 is measured after installation in the vacuum apparatus and the start of operation. The better the performance of the cryopump 10 is, the lower the initial minimum temperature is. As the cumulative operation time of the cryopump becomes longer, the minimum temperature reached tends to increase gradually. For this reason, the better the cryopump, the longer the operation is performed until the difference between the minimum temperature reached from the initial minimum temperature increases and the temperature rises to the above required temperature range.

  If the deviation from the initial minimum temperature increases, it is considered that the deterioration of the cryopump 10 with time progresses. In such a case, due to the accumulation of deterioration over time, in the worst case, there is a possibility that the cryopump 10 may suddenly become abnormal without obtaining any sign from the monitoring of the vacuum process by the controller of the vacuum apparatus. If an abnormality occurs in the cryopump 10, it causes a downtime of the vacuum apparatus, which is not preferable. However, by monitoring the cryopump 10 using the third monitoring condition described above, it is possible to detect that the deviation from the initial minimum temperature has increased. Therefore, it is preferable because maintenance of the cryopump can be promoted before an adverse effect on the vacuum process becomes apparent or before a sudden downtime occurs in the vacuum apparatus.

  In addition, the time degradation determination time is preferably longer than, for example, the setting time of the second monitoring condition, and more preferably longer than the time required for the baking process of the vacuum apparatus. By making the time degradation determination time longer than the time required for the baking process, it is possible to avoid erroneously determining that the temperature rise due to heat input during the baking process is a temperature increase due to time degradation. When the time degradation determination time is made shorter than the time required for the baking process, the CP controller 100 warns that the time degradation is truly occurring when the third monitoring condition is continuously established a plurality of times. You may make it output.

  When it is determined that the third monitoring condition is not satisfied (N in S16), the CP controller 100 determines whether or not the fourth monitoring condition is satisfied (S18). If it is determined that the fourth monitoring condition is satisfied (Y in S18), the CP controller 100 outputs a warning (S24).

  The fourth monitoring condition is that the operating frequency of the refrigerator motor 26 continues to rise to the monitoring frequency range for a set time or longer. The CP controller 100 starts timing when the operating frequency newly reaches the monitoring start frequency in the current monitoring process. The CP controller 100 determines whether or not the operating frequency exceeds the monitoring cancellation frequency in the subsequent monitoring processing, and determines whether or not the elapsed time exceeds the set time if it exceeds. When the set time is exceeded, the CP controller 100 determines that the fourth monitoring condition is satisfied. When the operating frequency returns below the monitoring cancellation frequency, the elapsed time count is reset, and it is determined that the fourth monitoring condition is not satisfied.

  The set time is preferably longer than the time required for the baking process of the vacuum apparatus, and is set to, for example, about several hours to several days. Both the monitoring start frequency and the monitoring cancellation frequency are set to values that are larger than the maximum operating frequency assumed during the vacuum processing and smaller than the upper limit frequency allowed for the refrigerator motor 26. The monitoring start frequency is set to a value larger than the monitoring cancellation frequency. In this way, the continuous increase in the operating frequency of the refrigerator motor 26 is due to the deterioration of the cryopump performance associated with the first-stage cryopanel or due to the baking process in the vacuum apparatus. Can be estimated.

  When it is determined that the fourth monitoring condition is not satisfied (N in S18), the CP controller 100 determines whether or not the fifth monitoring condition is satisfied (S20). If it is determined that the fifth monitoring condition is satisfied (Y in S20), the CP controller 100 outputs a warning (S24).

  The fifth monitoring condition is that the first-stage cryopanel temperature does not return below the reference temperature within the reference return time after the operating frequency of the refrigerator motor 26 reaches the upper limit value. The reference return time is more preferably shorter than the time required for the baking process of the vacuum apparatus, and is set within several hours, for example. The reference temperature is set to be higher than the target temperature, but is preferably lower than the warning temperature at which a warning is output in the vacuum apparatus.

  The CP controller 100 starts timing when the operating frequency newly reaches the upper limit frequency in the current monitoring process. The CP controller 100 determines whether or not the first-stage cryopanel temperature has been cooled below the reference temperature in the subsequent monitoring processing, and if not, determines whether or not the elapsed time has exceeded the reference return time. To do. If the reference return time is exceeded, the CP controller 100 determines that the fifth monitoring condition is satisfied. When the first-stage cryopanel temperature is cooled below the reference temperature, the elapsed time count is reset, and it is determined that the fifth monitoring condition is not satisfied. When the first-stage cryopanel temperature is equal to or lower than the reference temperature when the operation frequency reaches the upper limit value, the CP controller 100 may determine that the fifth monitoring condition is not satisfied.

  When it is determined that the fifth monitoring condition is not satisfied (N in S20), the CP controller 100 determines whether the sixth monitoring condition is satisfied (S22). If it is determined that the sixth monitoring condition is satisfied (Y in S22), the CP controller 100 outputs a warning (S24). When it is determined that the sixth monitoring condition is not satisfied (N in S22), the CP controller 100 ends the monitoring process without outputting a warning and waits until the next process.

  The sixth monitoring condition is that it is estimated that performance deterioration has occurred in the drive unit of the refrigerator 12. Specifically, the CP controller 100 is configured such that the operating frequency of the refrigerator motor 26, the temperature of the first-stage cryopanel, and the temperature of the second-stage cryopanel all exceed a threshold value for a set time or longer. In addition, it is determined that performance deterioration has occurred in the drive unit of the refrigerator 12. If the first-stage cryopanel and the second-stage cryopanel are not sufficiently cooled even though the operation frequency of the refrigerator motor 26 is increased, it is estimated that performance deterioration has occurred in the drive unit of the refrigerator 12. can do.

  For example, the threshold value of the operating frequency is set equal to the monitoring start frequency of the fourth monitoring condition. The threshold value of the first-stage cryopanel temperature is set equal to the reference temperature of the fifth monitoring condition. The threshold value of the two-stage cryopanel temperature is set equal to the caution temperature of the second monitoring condition. Thus, by sharing the threshold value, it is possible to divert the determination of other monitoring items. The set time is set equal to the set time of the second monitoring condition.

  Further, when the operation frequency of the refrigerator motor 26 and the temperature of the first-stage cryopanel continue to exceed the threshold, the temperature of the second-stage cryopanel returns to the threshold or lower. Experience has shown that there is a high probability that a baking process is being performed in the apparatus. Therefore, the CP controller 100 continues when the operating frequency of the refrigerator motor 26 and the temperature of the first-stage cryopanel exceed the threshold for a set time and the temperature of the second-stage cryopanel returns within the set time. Alternatively, it may be determined that the baking process is being performed in the vacuum apparatus.

  FIG. 4 is a flowchart for explaining a monitoring process according to another embodiment. The process shown in FIG. 4 is repeatedly executed by the CP controller 100 at a predetermined cycle during operation of the cryopump 10. The CP controller 100 monitors the operating gas pressure of the compressor 40 while the monitoring start condition is satisfied. The CP controller 100 outputs a warning when the operating gas pressure continues to decrease. The CP controller 100 may execute both the processes shown in FIGS. 3 and 4 or may execute only the process shown in FIG. In the following description, it is assumed that a plurality of cryopumps 10 are connected to the compressor 40 and supplied with working gas. However, the same monitoring process can be executed even when one cryopump 10 is connected to the compressor 40.

  The CP controller 100 first determines whether or not the compressor monitoring condition is satisfied (S30). Here, the compressor monitoring condition is that the operation mode of at least one cryopump 10 is under T1 temperature control, and not all cryopumps 10 are being regenerated. When it is determined that the compressor monitoring condition is not satisfied (N in S30), the CP controller 100 ends the process without monitoring the compressor operating state. Therefore, for example, when all the cryopumps 10 are in a stopped state or when at least one cryopump 10 is in a regeneration operation, the CP controller 100 does not perform the monitoring process of the compressor 40.

  When it is determined that the compressor monitoring condition is satisfied (Y in S30), the CP controller 100 determines whether or not the working gas pressure of the compressor 40 is decreased (S32). The CP controller 100 determines whether or not the measurement pressure of the first pressure sensor 43 that measures the working gas pressure on the discharge side of the compressor 40, that is, the high-pressure side, continuously falls below the reference pressure for a set time. For example, the reference pressure may be a lower limit value of a recommended pressure range defined as a specification of the compressor. For example, the set time is set to be approximately the same as the set time of the sixth monitoring condition described above. Instead of the first pressure sensor 43, the measurement pressure of the second pressure sensor 45 that measures the working gas pressure on the suction side, that is, the low pressure side of the compressor 40 may be used.

  If it is determined that the measured pressure continues to fall below the reference pressure for a set time (Y in S32), the CP controller 100 outputs a warning (S34). On the other hand, when the measured pressure returns to the reference pressure or higher within the set time (N in S32), the CP controller 100 ends the monitoring process without outputting a warning and waits for the next process. Specifically, the CP controller 100 starts measuring time when the working gas measurement pressure newly falls below the reference pressure in the current monitoring process. The CP controller 100 determines whether or not the measured pressure remains lower than the reference pressure in the monitoring process after the next time, and determines whether or not the elapsed time exceeds the set time if it remains. If the set time is exceeded, the CP controller 100 outputs a warning. When the measured pressure returns to the reference pressure or higher within the set time, the elapsed time count is reset. In this way, it is possible to monitor the pressure drop due to leakage of the working gas or the like.

  The compressor may be monitored when at least one cryopump 10 is in the regeneration operation. In this case, the compressor monitoring condition is that the operation mode of at least one cryopump 10 is under T1 temperature control. However, when there is a cryopump during the regeneration operation, the working gas pressure increases or decreases as compared with a normal exhaust operation (for example, during T1 temperature control). Therefore, it is preferable to adjust the reference pressure as appropriate. For example, since the operating gas pressure tends to increase during the temperature raising process in the regeneration operation as compared with the exhaust operation, it is preferable to increase the reference pressure. Further, since the working gas pressure tends to decrease during the cooling process in the regeneration operation as compared with the exhaust operation, it is preferable to lower the reference pressure.

  DESCRIPTION OF SYMBOLS 10 Cryopump, 12 Refrigerator, 14 Panel structure, 16 Heat shield, 22 1st cooling stage, 23 1st temperature sensor, 24 2nd cooling stage, 25 2nd temperature sensor, 26 Refrigerator motor, 28 Closure part , 31 opening, 32 baffle, 40 compressor, 43 first pressure sensor, 45 second pressure sensor, 60 motor for compressor, 100 CP controller.

Claims (4)

A cryopump comprising a refrigerator and a cryopanel cooled by the refrigerator;
A compressor for supplying working gas to the refrigerator;
A control unit for controlling the cryopump,
The control unit monitors the working gas pressure of the compressor ,
A plurality of cryopumps are connected to the compressor,
The vacuum evacuation system , wherein the controller monitors the compressor when the cryopanel is controlled to a target temperature in at least one cryopump and all the cryopumps are not being regenerated .   The vacuum exhaust system according to claim 1, wherein the control unit controls an operating frequency of the refrigerator so as to control the cryopanel to a target temperature.   The vacuum exhaust system according to claim 1, wherein the control unit controls an operating frequency of the compressor so as to control a differential pressure between the inlet and outlet of the compressor to a target pressure. Wherein, the vacuum evacuation system according to any of claims 1 to 3, characterized in that the operating gas pressure of the compressor to monitor whether below continues the reference pressure set time or more.

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