Cryopump performance monitoring

Abstract

A method for monitoring the performance of a cryopump (5), a performance monitoring circuit (14), and a cryopump (5) are disclosed, the method including controlling the cryopump (5) after completion of a regeneration cycle to execute a predetermined test routine that tests the performance of the cryopump under predetermined conditions, monitoring the cryopump (5) during the predetermined test routine to collect data indicative of the performance of the cryopump (5), and storing the data collected during the monitoring.

Description

[Technical field]

[0001] The field of the invention relates to cryopumps and methods and circuits for monitoring the performance of cryopumps. [Background technology]

[0002] Cryopumps work on the principle of condensing or trapping the pumped gas. This means that cryopumps need to be periodically regenerated to remove the trapped gas. Regeneration involves isolating the pump from the vacuum system and warming it while introducing a purge gas to dilute the trapped gas that has been desorbed or vaporized by the warming.

[0003] If a cryopump / system does not perform according to specifications and degrades slowly but without impacting the customer's process, it can fail unexpectedly, which can be very costly to the cryopump user, especially if the cryopump is used in a process such as an integrated circuit manufacturer. Summary of the Invention [Problem to be solved by the invention]

[0004] It would be desirable to provide a method and / or diagnostic system that can monitor the current health or performance of a cryopump, determine pump degradation, and therefore predict future performance problems or failures. The ability to predict performance degradation allows a service engineer to intervene before the degradation unduly impacts the pumping process. [Means for solving the problem]

[0005] A first aspect provides a method for monitoring performance of a cryopump, the method comprising the steps of controlling the cryopump to execute a predetermined test routine after completion of a regeneration cycle to test performance of the cryopump under predetermined conditions, monitoring the cryopump during the predetermined test routine to collect data indicative of performance of the cryopump, and storing the data indicative of the pump collected during monitoring.

[0006] Cryopumps are periodically regenerated to remove accumulated condensed gas. This is done while the pump is not being used to pump the vacuum chamber; during regeneration, the pump is generally under the control of the control circuitry associated with the pump, rather than being actively used to cryopump process gases within the vacuum chamber. Additionally, the gate valve to the vacuum chamber is closed.

[0007] Furthermore, when the regeneration cycle is completed, the state of the pump is known and the gate valve of the vacuum chamber pumped by the pump is closed. This therefore provides a period that is ideal for running a test routine, since the vacuum system pumped by the pump will not be affected and the state of the pump is known. The behavior of the pump during the test routine run at this time will therefore be indicative of the current performance of the pump, independent of the vacuum system it pumps and the condensed material collected. This means that any comparison of the current test with a previous test run under approximately the same conditions will provide an accurate picture of not only the current health of the pump, but also an indication of how this health or performance has changed over time. In addition, since the regeneration is performed periodically, this provides an opportunity to run tests regularly, and therefore to monitor any degradation of the pump regularly.

[0008] In some embodiments, the method includes controlling the cryopump to perform a predetermined test routine periodically after at least a subset of the regeneration cycles.

[0009] It is desirable for any pump test routines to be run periodically to monitor pump degradation and be able to predict pump failure in advance. Because regeneration cycles are performed periodically, the test routine may be run after a percentage of these regeneration cycles, perhaps after each regeneration cycle, or perhaps after every other regeneration cycle.

[0010] In some embodiments, the method includes the further step of determining the performance of the pump from the collected data.

[0011] The collected data is indicative of the current performance of the pump, and the method can analyze the data to determine the performance.

[0012] In some embodiments, determining the performance of the pump includes comparing data obtained from a current test routine with data obtained from a previous test routine.

[0013] The absolute value of the data obtained from the test routine indicates the current performance of the pump and by comparing it with data from other previous test results it provides a useful indication of any change in the pump's performance, indeed the rate of change in the pump's performance, and therefore this comparison can help provide a prediction of when the pump may fail.

[0014] In some embodiments, the method includes the further step of outputting data indicative of the performance of the pump.

[0015] The collected data may be output. The collected data may be output as raw data or processed data, and in some embodiments, as an indicator of the pump's performance. The indicator may be accessible to a pump operator. The indicator may be in the form of a numerical performance indication or a color-coded indication. When performance is determined to be poor, the indicator may indicate that a service engineer's input is desirable. The pump performance indicator may be generated in response to the collected data values ​​and / or in response to a change in the collected data values ​​as compared to the collected data values ​​during a previous test. A change in the collected values ​​indicates a deterioration in the pump's performance, which provides a basis for predicting the future performance of the pump so that the pump can be replaced before it fails or its performance deteriorates too much.

[0016] In some embodiments, outputting the data includes receiving a request for the data and outputting the data in response to the request.

[0017] The request may be from a service engineer at the pump's site and the data may be output via a port on the pump, or the data may be a request from a remote server and the data may be output over a network to the remote server.

[0018] In some embodiments, the predetermined test routine includes determining the level of cooling provided by the cryopump at a given motor speed.

[0019] A predetermined test routine is one in which the pump is operated in a predetermined manner and the performance of the pump is measured. In some cases, the test routine may include operating the cryopump at a constant, predetermined motor speed and measuring the level of cooling provided by the cryopump at this motor speed. In this regard, the cryopump may have a variable speed motor that pumps a coolant, such as helium gas, around the refrigeration system. The speed of the motor affects the speed at which the coolant is pumped around the system and therefore the cooling capacity that the system can provide. If the motor speed is set to a constant, the cooling capacity at this speed is indicative of the current performance and effectiveness of the cryopump. Thus, running the motor at a predetermined speed and then determining how much cooling is provided by the cryopump is an indication of the pump's performance.

[0020] In some embodiments, controlling the cryopump to perform a predetermined test routine includes controlling a variable speed motor that controls the flow of refrigerant through a refrigeration system of the cryopump to operate at a predetermined speed, setting a first predetermined temperature of a first stage of the refrigerator and a second predetermined temperature of a second stage of the refrigerator, and controlling heaters associated with the first and second stages of the refrigerator so that the first and second predetermined temperatures are maintained, and determining the performance of the cryopump includes determining the power applied to the heaters that maintain the first and second predetermined temperatures.

[0021] One way to determine the level of cooling provided by the cryopump can be by setting predetermined temperatures for the first and second stages of the refrigerator, which in some cases can be selected to be the normal temperatures of operation of the cryopump, and determining the power consumed by heaters associated with those stages of the refrigerator to maintain those temperatures. The level of cooling provided by the cryopump is a function of the power applied to the heaters. In this regard, as the performance of the cryopump deteriorates over time, the cooling provided by the pump decreases and the amount of power applied to the heaters to maintain the temperature also decreases, indicating a deterioration in performance.

[0022] In some embodiments, the method further includes receiving an input indicative of at least one of a predetermined temperature and a predetermined motor speed, the method being configured to perform a subsequent test routine using the received at least one of the predetermined temperature and the motor speed.

[0023] In some embodiments, a service engineer may be able to update the predetermined temperature and / or motor speed of the test if it is deemed desirable to change the test conditions, perhaps to reflect current or future use conditions of the cryopump.

[0024] A second aspect provides a computer program comprising computer readable instructions which, when executed by a processor, control the processor to perform steps in a method according to the first aspect.

[0025] A third aspect provides a control and diagnostic circuit for a cryopump, the control circuit being configured to determine when a regeneration cycle is completed, control the cryopump after completion of the regeneration cycle, and execute a predetermined test routine to test performance of the cryopump under predetermined conditions, and the diagnostic circuit being configured to monitor performance of the cryopump during the predetermined test routine, and store data indicative of the performance obtained from the monitoring.

[0026] In some embodiments, the control circuitry is configured to control the cryopump to perform a predetermined test routine periodically after at least a subset of the regeneration cycles.

[0027] In some embodiments, the diagnostic circuitry is configured to determine the performance of the pump from the collected data.

[0028] In some embodiments, the diagnostic circuitry is configured to determine the performance of the pump by comparing data obtained from a current test routine with data obtained from a previous test routine.

[0029] In some embodiments, the diagnostic circuitry is configured to output data indicative of the performance of the pump.

[0030] In some embodiments, the diagnostic circuitry is configured to output the data in response to receiving a request for the data.

[0031] In some embodiments, the predetermined test routine includes determining the level of cooling provided by the cryopump at a given motor speed.

[0032] In some embodiments, the control circuitry is configured to control the cryopump to perform a predetermined test routine by controlling a variable speed motor that controls the flow of refrigerant through a refrigeration system of the cryopump to operate at a predetermined speed, setting a first predetermined temperature of a first stage of the refrigerator and a second predetermined temperature of a second stage of the refrigerator, and controlling heaters associated with the first and second stages of the refrigerator such that the first and second predetermined temperatures are maintained, and the diagnostic circuitry is configured to determine the power applied to the heaters that maintain the first and second predetermined temperatures.

[0033] A fourth aspect provides a cryopump comprising a refrigerator unit, a variable speed motor for controlling a flow of refrigerant through a cooling system of the cryopump, and a control and diagnostic circuit according to the third aspect.

[0034] In some embodiments, the refrigerator unit includes a two-stage refrigerator, and the cryopump further includes a temperature sensor monitoring a temperature of a first stage of the refrigerator, a temperature sensor monitoring a temperature of a second stage of the refrigerator, a heater providing heat to the first stage of the refrigerator, and a heater providing heat to the second stage of the refrigerator.

[0035] In some embodiments, the control circuitry is further configured to control regeneration of the pump.

[0036] The regeneration cycle performed by the pump will be under the control of control circuitry associated with the pump, and this same control circuitry can be used to control the execution of the test routine.

[0037] Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims, as appropriate, in combinations other than those explicitly set out in the claims.

[0038] Where features of an apparatus are described as operable to provide a function, this should be understood to include features of the apparatus that provide that function or that are adapted or configured to provide that function.

[0039] Hereinafter, embodiments of the present invention will be further described with reference to the accompanying drawings. [Brief description of the drawings]

[0040] [Figure 1] 1 illustrates a cryopump and control and diagnostic circuitry according to an embodiment. [Diagram 2] 4 is a flow diagram illustrating steps according to a method according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Before describing this embodiment in more detail, an overview will first be provided.

[0042] Embodiments provide software-based functionality that can help determine the pump's ability to function in a customer's operating environment. The software-based functionality controls the pump to perform diagnostic tests after a regeneration cycle, and information gathered during periodic diagnostic tests can be used by a service engineer to help determine the pump's current refrigeration capacity.

[0043] In some embodiments, the cryopump is configured with a variable speed motor and operates at multiple operating speeds including 72 rpm and multiple first and second stage operating temperatures including 65 K, 13.5 K. During a test routine, the pump can be controlled to operate at constant operating conditions where the first and second stage temperatures are typically 65 K, 13.5 K, and the motor is at 72 RPM, and there will be a resulting amount of heater power applied to the heater, which can be measured as a % of maximum or actual watts. These power measurements are indicative of the available refrigeration capacity and therefore the performance of the cryopump.

[0044] In some embodiments, new pumps will be tested with a test routine and the results will be compared to the results of subsequent test routines run after each regeneration at the customer's tool. The results from the production test and the first regeneration will be used as a baseline to monitor the performance of the pump after each cool down to maintain a running trend line of performance.

[0045] The cryopump will be regenerated in the normal manner and then a "sanity check" can be performed by running a test routine during the "cool down" phase of the setup routine.

[0046] This procedure can be performed with the heat load calculated in watts applied by the module to maintain a given temperature, such as 65K for the first stage, 13.5K for the second stage, etc., at a set motor / regenerator speed.

[0047] In some embodiments, the control circuitry will also provide an option that allows a service engineer to run a diagnostic sanity check on parameters of their choice by sending special commands to the module.

[0048] Regeneration is the process of warming the cryopanel surfaces with electric heaters located on the first and second stages. N2 gas is utilized to dilute the H2 gas pumped to the charcoal in the second stage of the implant pump. The rough / purge process is then used to clean each stage of the cryopump at high temperatures such as 310K, and sometimes up to 330K, to release the trapped gases through the pressure relief valves into the gas scrubber.

[0049] The cryopump is then cooled to a set temperature, in one embodiment 290K, and pumped to a set vacuum level, e.g., 50 microns, after which a rate of rise test ROR is performed until it exceeds a predetermined value, e.g., 10 microns / min, to check the pumping effectiveness.

[0050] After passing the ROR, the motor is started and the cryopump cools down to its base temperature, which in some embodiments, such as an implant pump, is 65K / 13.5K, and after a sanity check, the cryopump is ready for the user and is "regenerated."

[0051] Cryopumps use a variable speed motor, anything from 30 to 144 rpm in some embodiments, to drive a regenerator within a cylinder to utilize the expansion of helium to cool the two "stages" of the refrigerator.

[0052] The regenerator revolutions per minute directly affects the cooling power or wattage the refrigerator can provide to maintain the set temperature.

[0053] Regeneration is described as the pump going through a set routine which warms, purges and vents the pump so it can cool down to operating temperature, and regeneration complete signals to the customer that the pump is ready for use.

[0054] This test routine can be run after a regeneration and any time a service engineer has access to the cryopump module and commands the test routine. Performance can be compared to previous tests to predict the performance of the cryopump / system with the help of the service engineer.

[0055] Performance, reliability and safety are vital to pump users and being able to anticipate the unexpected is of utmost importance.

[0056] The sanity check routine is designed to check the performance of the pump over time and to assist the service engineer in identifying possible degradation to this performance.

[0057] This allows a service engineer to visit the customer to diagnose a possible problem with the system in order to mitigate the issue, which may involve servicing the system before disrupting the customer's process, removing / repairing pumps / compressors or accessories, etc., thereby reducing system tool downtime.

[0058] Data collected during the test routines is stored on a data storage device associated with the pump and can be retrieved from the data storage device by a service engineer or transmitted to a remote server which analyzes the data in response to a signal received from the remote server requesting the data. The data can be analyzed to determine both the current performance of the pump and changes in performance over time.

[0059] 1 shows a cryopump 5 according to one embodiment. The cryopump 5 is cooled by a refrigeration unit 16 controlled by control and diagnostic circuitry 14. The refrigeration unit 16 includes a first stage with a cold finger extending into the cryopump vessel and cooling the interior surface of the vessel and a frontal array (not shown) disposed across the inlet 7, and a second stage that cools the cryopanels 10 to a temperature lower than that of the first stage. The refrigerator includes a variable speed motor 17 that pumps a refrigerant, in this case helium, around the refrigeration system.

[0060] There are heaters 18a and 18b associated with the first and second stage refrigerators, respectively, which can be used to provide heat during regeneration and testing of the cryopump.

[0061] The cryopump 5 is used to evacuate the vacuum chamber to a high vacuum. The vacuum chamber may be used, for example, for semiconductor processing such as semiconductor manufacturing. The cryopump is a trapping pump, meaning that gas molecules entering the cryopump are trapped by condensing or adsorbing them on the cooled surfaces of the cryopump. This means that the cryopump needs to be periodically regenerated to remove the trapped condensed gases.

[0062] The control circuit 14 controls the operation of the cryopump and, during cryopump regeneration, controls the regeneration cycle. During the regeneration cycle, the cryopump is isolated from the vacuum chamber, typically by a gate valve, and heaters 18a, 18b are used to raise the temperature of the cryopump, while a purge gas is turned on to remove the evaporated molecules. This regeneration occurs periodically when the condensed material in the pump exceeds a value that prevents the pump from operating efficiently.

[0063] In addition to controlling the regeneration cycle, the control and diagnostic circuitry 14 can be configured to execute a test routine upon completion of a regeneration cycle if the condition of the cryopump is known. This test routine is used to determine the health or performance of the pump and allows monitoring for degradation in pump performance and predicting pump failure before it occurs. Unexpected pump failures can be very costly, especially when used in semiconductor manufacturing, so predicting failures in advance and allowing the pump to be replaced before it fails has many advantages.

[0064] The test routine is used to determine the current cooling capacity of the cryopump 5 while the motor in the refrigeration unit 16 is running at a constant speed. The motor in the refrigeration unit 16 pumps the refrigerant, in this case helium, around the refrigeration system and is typically a variable speed motor, allowing the pump capacity and cooling power to be changed. During the test routine, the pump speed is set to a predetermined value and the temperature sensors 12a and 12b are used to determine the temperature of the first and second stage refrigerators and send a signal to the circuit 14. The circuit 14 controls the heaters 18a and 18b associated with the first and second stage refrigerators such that the temperatures of the first and second stage refrigerators are maintained at certain predetermined values. These values ​​may be selected as the normal operating temperatures of the cryopump. The amount of power required by the heaters to maintain this temperature is indicative of the cooling power of the cryopump 5 and may be stored in the data storage device 13. A service engineer may then access this data storage device to determine the current performance and performance changes, along with the rate of change of the cryopump's performance over time.

[0065] In some embodiments, an input / output port 19 is also provided that can be used to output the current performance of the cryopump to an operator. This can be output as an indicator that can be accessed by the pump operator. The indicator can be a number indicating the current performance of the pump, which can relate to a percentage of optimal performance, or simply a color indicating whether the current performance is good or not so good. In some cases, the indicator can include an indication that a service engineer should be contacted. In other cases, the data can be output via the transmitter to a configured remote server. This can occur in response to receiving a request for data from the remote server. The remote server can be a server configured to analyze data received from multiple pumps and monitor their performance and any performance changes from this data.

[0066] In some embodiments, the input / output port 19 may also be used to receive values ​​entered by a service engineer indicating the motor speed and / or first and second stage temperatures used in the test routine, allowing these values ​​to be updated as necessary. In this regard, depending on the operating conditions of the pump, different temperatures and / or motor speeds may be more appropriate for testing the pump.

[0067] 2 is a flow diagram illustrating steps in a method for monitoring the performance or health of a pump according to an embodiment.First, in step D5, it is determined whether the regeneration cycle is complete.

[0068] Once it is determined that the regeneration cycle is complete, a test routine is initiated in step S10. In this regard, in some embodiments, S10 may be initiated only after completion of a certain number of regeneration cycles, instead of being performed after each regeneration cycle. In this case, there may be an intermediate step of determining whether a counter has counted up to this certain number, with the counter being incremented after each regeneration cycle is completed.

[0069] When the test routine is started, in step S20, the motor speed is set to a predetermined value and cooling of the cryopump begins. In step S30, the first and second stage temperatures are set to predetermined values. The predetermined temperatures and motor speeds may be set values ​​of the control / diagnostic circuitry and / or may be values ​​that can be updated in response to input by a service engineer. In step S40, the heaters are controlled to maintain the first and second stage refrigerator temperatures at the desired predetermined temperatures. Since the power consumed by the heaters to maintain the temperature is indicative of the current performance of the cryopump, in step S50, the power applied to and consumed by the heaters is determined and in step S60, this value is stored as an indication of the performance of the pump. This value may be stored along with an indication of the regeneration cycle in which the test routine was subsequently performed in which the value was obtained.

[0070] At S70, the current power may be compared to a previous value to determine the change and / or rate of change in pump performance. This may be used together with the actual determined power value to determine the current pump performance. In some embodiments, an indication of the current performance may be output at step S80. The pump regeneration cycle and test is now complete and normal operation resumes. The diagnostic circuitry then proceeds to determine whether the next regeneration cycle has been initiated at step D15, and if so, the diagnostic circuitry waits until that cycle is completed, after which the diagnostic circuitry may begin the test routine again at S10.

[0071] Although exemplary embodiments of the present invention are disclosed in detail herein with reference to the accompanying drawings, it should be understood that the present invention is not limited to the precise embodiments, and various changes and modifications can be made therein by those skilled in the art without departing from the scope of the present invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0072] 5. Cryopump 7 Entrance 10 Cryopanel 12a, 12b Temperature sensor 13 Data storage devices 14 Control and diagnostic circuits 16 Refrigeration Unit 17 Variable Speed ​​Motor 18a, 18b heater 19 Input / Output Ports

Claims

1. 1. A method for monitoring performance of a cryopump, comprising: after completion of a regeneration cycle, controlling the cryopump to execute a predetermined test routine to test the performance of the cryopump under predetermined conditions; monitoring the cryopump during the predetermined test routine to collect data indicative of the performance of the cryopump; storing the data indicative of the performance collected during the monitoring; Including, The step of controlling the cryopump to execute a predetermined test routine comprises: controlling a variable speed motor that controls the flow of refrigerant through a refrigeration system of the cryopump to operate at a predetermined speed; setting a first predetermined temperature for a first stage of a refrigerator and a second predetermined temperature for a second stage of the refrigerator; controlling heaters associated with the first and second stages of the refrigerator such that the first and second predetermined temperatures are maintained; Including, A method, wherein determining the performance of the cryopump includes determining power applied to the heater to maintain the first and second predetermined temperatures.

2. The method of claim 1 , further comprising controlling the cryopump to perform the predetermined test routine periodically after at least a subset of the regeneration cycles.

3. The method of claim 1 or 2, comprising the further step of determining the performance of the pump from the collected data.

4. 4. The method of claim 3, wherein determining the performance of the pump comprises comparing data obtained from a current test routine with data obtained from a previous test routine.

5. The method of claim 1 , wherein the method comprises the further step of outputting data indicative of performance of the pump.

6. The method of claim 5 , wherein outputting the data comprises receiving a request for the data and outputting the data in response to the request.

7. 7. The method of claim 1, wherein the predetermined test routine includes determining a level of cooling provided by the cryopump at a given motor speed.

8. A computer program comprising computer readable instructions which, when executed by a processor, controls the processor to perform the steps of the method according to any one of claims 1 to 7.

9. 1. A cryopump control and diagnostic circuit, comprising: the control circuitry is configured to determine when a regeneration cycle is completed and to control the cryopump after completion of the regeneration cycle to execute a predetermined test routine to test performance of the cryopump under predetermined conditions; The diagnostic circuitry includes: monitoring the performance of the cryopump during the predetermined test routine; storing data indicative of said performance obtained from said monitoring; It is configured as follows: The control circuit includes: controlling a variable speed motor that controls the flow of refrigerant through a refrigeration system of the cryopump to operate at a predetermined speed; setting a first predetermined temperature for a first stage of a refrigerator and a second predetermined temperature for a second stage of the refrigerator; controlling heaters associated with the first and second stages of the refrigerator such that the first and second predetermined temperatures are maintained; and configured to control the cryopump to perform the predetermined test routine by The control and diagnostic circuitry, wherein the diagnostic circuitry is configured to determine the power applied to the heater to maintain the first and second predetermined temperatures.

10. The control and diagnostic circuit of claim 9 , wherein the control circuitry is configured to control the cryopump to perform the predetermined test routine periodically after at least a subset of the regeneration cycles.

11. 11. A control and diagnostic circuit as claimed in claim 9 or 10, wherein the diagnostic circuit is configured to determine performance of the pump from the collected data.

12. 12. The control and diagnostic circuit of claim 11, wherein the diagnostic circuit is configured to determine the performance of the pump by comparing data obtained from a current test routine with data obtained from a previous test routine.

13. 13. A control and diagnostic circuit as claimed in any one of claims 9 to 12, wherein the diagnostic circuit is configured to output data indicative of performance of the pump.

14. The control and diagnostic circuitry of claim 13 , wherein the diagnostic circuitry is configured to output the data in response to receiving a request for the data.

15. 15. A control and diagnostic circuit as claimed in any one of claims 9 to 14, wherein the predetermined test routine includes determining the level of cooling provided by the cryopump at a given motor speed.

16. 1. A cryopump comprising: A refrigerator unit; a variable speed motor for controlling the flow of refrigerant through a cooling system of the cryopump; A control and diagnostic circuit according to any one of claims 9 to 15; A cryopump equipped with

17. The refrigerator unit includes a two-stage refrigerator, and the cryopump includes: a temperature sensor for monitoring a temperature of a first stage of the refrigerator; and a temperature sensor for monitoring a temperature of a second stage of the refrigerator. a heater that supplies heat to the first stage refrigerator; and a heater that supplies heat to the second stage refrigerator.

17. The cryopump of claim 16, further comprising:

Images