A cryopump regenerative heating system and method

Abstract

The application belongs to the technical field of cryogenic pumps, and particularly relates to a cryogenic pump regeneration heating system and a regeneration heating method. t The state of the cold plate is evaluated according to the condensation layer area and the condensation layer temperature of the cold plate to be treated of the cryogenic pump, and when the cold plate to be treated is in an abnormal state, a cold plate temperature adjustment value C The state of the cold plate is evaluated according to the condensation layer area and the condensation layer temperature of the cold plate to be treated of the cryogenic pump, and when the cold plate to be treated is in an abnormal state, a cold plate temperature adjustment value C The state of the cold plate is evaluated according to the condensation layer area and the condensation layer temperature of the cold plate to be treated of the cryogenic pump, and when the cold plate to be treated is in an abnormal state, a cold plate temperature adjustment value C

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cryogenic pumps, and particularly relates to a cryogenic pump regeneration heating system and a regeneration heating method. BACKGROUND

[0002] A cryogenic pump is a vacuum obtaining device that uses a low-temperature surface to condense, adsorb and capture gas, and is widely used in the fields of semiconductors, integrated circuits and space technology research. After working for a period of time, the cold head of the cryogenic pump is covered with solid condensed by gas, which causes the surface temperature to rise and the adsorption of gas to weaken or even stop. In order to restore the pumping function of the cryogenic pump, it needs to be heated to make the condensed matter adsorbed on the cold head vaporize and discharge, and this process is called "regeneration".

[0003] In a cryogenic pump system, the regeneration process of the pump is a key link. At present, the regeneration heating methods of the cryogenic pump mainly include natural heating method, gas discharge heating method and electric heating method. The natural heating method has slow and uneven heating speed; and the gas discharge heating method and the electric heating method often use fixed power or simple heating means, which makes the temperature control not accurate enough, resulting in low regeneration efficiency and phenomena of excessive temperature fluctuation or heat waste.

[0004] For some precision equipment or systems, especially for applications involving the delivery of low-temperature liquid, it is crucial to accurately control the cold plate temperature and improve the regeneration efficiency. It is necessary to provide a new cryogenic pump regeneration heating system and method. SUMMARY

[0005] In order to solve the above problems, one of the purposes of the present application is to provide a cryogenic pump regeneration heating method.

[0006] The application adopts the following technical solutions:

[0007] A cryogenic pump regeneration heating method, according to the condensation layer area and the condensation layer temperature of the cold plate to be processed of the cryogenic pump, the state of the cold plate to be processed is evaluated, when the cold plate to be processed is in an abnormal state, the cold plate temperature adjustment value is obtained The cold plate temperature is adjusted;

[0008] Comprising the following steps:

[0009] S1. Obtain the condensation layer area and the condensation layer temperature of the cold plate to be processed, and calculate the cold plate state evaluation value according to the following formula According to the calculated cold plate state evaluation value, the state of the cold plate to be processed is evaluated:

[0010] ;

[0011] In the formula, is a condensation layer area factor, is an abnormal area factor, is a temperature difference factor, , , is a weight coefficient and ;

[0012] S2. Compare the cold plate state evaluation value with the cold plate state evaluation threshold value, when the cold plate state evaluation value exceeds the cold plate state evaluation threshold value, it is determined that the cold plate to be processed is in an abnormal state, and step S3 is performed, otherwise it is in a normal state, and returns to step S1;

[0013] S3. According to the following temperature adjustment model, obtain the cold plate temperature adjustment value , and adjust the cold plate temperature:

[0014] ;

[0015] wherein, is the current temperature of the cold plate to be processed, is the ambient temperature evaluation value, is the low-temperature pump pumping speed evaluation value, , are weight coefficients, which are valued according to experience, and .

[0016] Preferably, the cold plate to be processed is divided into several detection areas according to area average, the sum of the cold plate area in all detection areas is the total detection area, and the sum of the condenser area on the cold plate in all detection areas is the total condenser area, then:

[0017] The condenser area factor ;

[0018] The condenser temperature and the cold plate temperature in each detection area are processed by difference, to obtain a temperature difference value, and the temperature difference value is compared with a temperature difference value preset range, if the temperature difference value is within the temperature difference value preset range, the detection area is marked as a normal area, otherwise, it is marked as an abnormal area, then:

[0019] The abnormal area factor ;

[0020] The temperature difference value of the abnormal area is compared with the two end point values of the temperature difference value preset range, and the temperature difference value is processed by difference with the end point value m closest to the temperature difference value, to obtain a temperature difference deviation value, then:

[0021] The temperature difference factor .

[0022] Preferably, the current ambient temperature of the cryogenic pump is obtained, the current ambient temperature is compared with two end values of a standard temperature range, one end value n closest to the current ambient temperature is selected, and a difference between the current ambient temperature and the end value n is obtained as an ambient temperature difference, then:

[0023] Ambient temperature evaluation value 。

[0024] Preferably, the current pumping speed of the cryogenic pump is obtained, the current pumping speed is compared with two end values of a standard pumping speed range, one end value o closest to the current pumping speed is selected, and a difference between the current pumping speed and the end value o is obtained as a pumping speed difference, then:

[0025] Cryogenic pump pumping speed evaluation value 。

[0026] Preferably, when there are multiple abnormal regions, the temperature difference deviation value with the maximum value is used to calculate the temperature difference factor 。

[0027] In the method, the cold plate state evaluation threshold, the temperature difference value preset range, the standard temperature range, and the standard pumping speed range are all empirical values, which are set according to actual needs.

[0028] The second object of the application is to provide a cryogenic pump regeneration heating system for executing the cryogenic pump regeneration heating method as described above.

[0029] The third object of the application is to provide a chip storing a program for executing the cryogenic pump regeneration heating method as described above.

[0030] The application has the following beneficial effects:

[0031] The application can judge the state of the cold plate in real time through the condensation layer area and the condensation layer temperature of the cold plate, can timely feedback the state of the cold plate, can analyze the cold plate state, the ambient temperature, and the cryogenic pump pumping speed, and can accurately adjust the temperature of the cold plate according to the analysis result, so that the condensation layer of the cold plate is kept within a standard range, the adsorption capacity of the cold plate is maintained, the accuracy of the cryogenic pump regeneration heating is improved, and the efficiency of the cryogenic pump regeneration heating is improved. DETAILED DESCRIPTION

[0032] The technical solutions of the application will be described in more detail below in combination with embodiments.

[0033] Embodiment 1

[0034] A cryogenic pump regeneration heating method, according to the condensation layer area and the condensation layer temperature of the cold plate to be processed of the cryogenic pump, evaluates the state of the cold plate to be processed, obtains a cold plate temperature adjustment value when the cold plate to be processed is in an abnormal state Adjusting the temperature of the cold plate.

[0035] comprising the following steps:

[0036] S1. dividing the cold plate to be processed into several detection areas in area average, the sum of the areas of the cold plate in all detection areas being the total detection area, the sum of the areas of the condensing layer on the cold plate in all detection areas being the total condensing layer area, calculating a condensing layer area factor :

[0037] ;

[0038] differencing the temperature of the condensing layer and the temperature of the cold plate in each detection area to obtain a temperature difference value, comparing the temperature difference value with a preset temperature difference value range, if the temperature difference value is within the preset temperature difference value range, marking the detection area as a normal area, otherwise, marking the detection area as an abnormal area; calculating an abnormal area factor :

[0039] ;

[0040] comparing the temperature difference value of the abnormal area with the two end point values of the preset temperature difference value range, selecting one end point value m closest to the temperature difference value and differencing the temperature difference value to obtain a temperature difference deviation value, calculating a temperature difference factor :

[0041] ;

[0042] when there are multiple abnormal areas, using the temperature difference deviation value with the largest value to calculate the above-mentioned temperature difference factor .

[0043] then, calculating a cold plate state evaluation value according to the following formula , evaluating the state of the cold plate to be processed according to the calculated cold plate state evaluation value:

[0044] ;

[0045] wherein, is the condensing layer area factor, is the abnormal area factor, is the temperature difference factor, , , is a weight coefficient and ;

[0046] S2. comparing the cold plate state evaluation value with a cold plate state evaluation threshold value, when the cold plate state evaluation value When the cold plate state evaluation threshold is exceeded, it is determined that the cold plate to be processed is in an abnormal state, and step S3 is performed, otherwise it is in a normal state, and step S1 is returned.

[0047] S3. Obtain the current environment temperature of the cryopump, compare the current environment temperature with the two endpoint values of the standard temperature range, select one endpoint value n closest to the current environment temperature, and perform difference processing on the current environment temperature to obtain an environment temperature difference, and calculate an environment temperature evaluation value

[0048]

[0049] Obtain the current pumping speed of the cryopump, compare the current pumping speed with the two endpoint values of the standard pumping speed range, select one endpoint value o closest to the current pumping speed, and perform difference processing on the current pumping speed to obtain a pumping speed difference, and calculate a cryopump pumping speed evaluation value

[0050]

[0051] Then, according to the following temperature adjustment model, obtain the cold plate temperature adjustment value , and adjust the cold plate temperature:

[0052]

[0053] wherein, is the current temperature of the cold plate to be processed, , are weight coefficients, which are empirically valued, and .

[0054] In the above method, the cold plate is a cooling component maintained at low temperature by liquid helium; when gas molecules collide with the surface of the cold plate, they will be cooled and condensed into solids or liquids to form a condensation layer. At this time, the temperature of the condensation layer should be close to the temperature of the cold plate, but if the condensation layer gradually thickens, there will be a certain thermal resistance, causing the surface temperature of the condensation layer to be slightly higher than the temperature of the cold plate. If the temperature difference between the condensation layer and the cold plate is too large, the temperature of the condensation layer may rise, the vapor pressure of the gas molecules will rise, and some of the condensed matter will re-evaporate, which will reduce the pumping efficiency of the cryopump and even destroy the vacuum environment; therefore, the temperature difference between the cold plate and the condensation layer needs to be kept within a certain range to ensure the stable existence of the condensed matter to continuously capture gas molecules. Therefore, the temperature difference value and the abnormal area factor and the temperature difference factor are introduced to correct the error caused by the thickness of the condensation layer.

[0055] Example 2

[0056] ​​​​​The low-temperature pump regeneration heating system for performing the low-temperature pump regeneration heating method in embodiment 1 comprises a data acquisition module, an analysis module and an adjustment module, the analysis module is electrically connected with the data acquisition module and the adjustment module respectively, wherein the data acquisition module comprises a temperature measuring device arranged on the cold plate, the adjustment module is used for adjusting the low-temperature pump, the analysis module processes the information acquired from the data acquisition module and outputs a cold plate temperature adjustment value Ct to the adjustment module.

[0057] Specifically, the data acquisition module can comprise:

[0058] A cold plate detection module is configured to divide the cold plate into a plurality of detection areas and acquire state data of the cold plate in the detection areas, wherein the state data comprises a condensation layer area and a condensation layer temperature.

[0059] An environment detection module is configured to detect a current environment temperature.

[0060] The analysis module comprises at least the following functions:

[0061] A cold plate state analysis module is configured to generate a cold plate state evaluation value according to the condensation layer area and the condensation layer temperature.

[0062] Further, the cold plate state analysis module further comprises:

[0063] An area analysis submodule is configured to generate a condensation layer area factor according to the condensation layer temperature.

[0064] An abnormal area analysis submodule is configured to generate an abnormal area factor according to the condensation layer temperature.

[0065] A temperature difference analysis submodule is configured to generate a temperature difference factor according to a temperature difference value, wherein the temperature difference value refers to a difference between the condensation layer temperature and the cold plate temperature.

[0066] A cold plate state judgment module is configured to judge whether the cold plate state is in an abnormal state according to the cold plate state evaluation value, and further, the cold plate state judgment module can comprise:

[0067] A cold plate state evaluation value generation submodule is configured to generate the cold plate state evaluation value according to the condensation layer area factor, the abnormal area factor and the temperature difference factor.

[0068] A cold plate temperature adjustment value generation module is configured to generate a cold plate temperature adjustment value according to the cold plate state evaluation value, an environment temperature evaluation value and a pumping speed evaluation value when the cold plate state is abnormal.

[0069] Further, the cold plate temperature adjustment value generation module further comprises:

[0070] An environment temperature evaluation submodule is configured to generate the environment temperature evaluation value according to the environment temperature.

[0071] The air exhaust speed evaluation submodule is configured to generate an air exhaust speed evaluation value according to the air exhaust speed.

[0072] The data output submodule is configured to establish an adjustment model, and to input the cold plate state evaluation value, the ambient temperature evaluation value, and the air exhaust speed evaluation value into the adjustment model to generate a cold plate temperature adjustment value.

[0073] The adjustment module includes a temperature control module configured to adjust the cold plate temperature according to the cold plate temperature adjustment value, for example, by controlling the power of a refrigerator in a cryogenic pump or adjusting the flow rate of liquid nitrogen.

[0074] Embodiment 3

[0075] A cryogenic pump uses the cryogenic pump regeneration heating method provided in the present application during operation, and the method is as follows:

[0076] 1. Initial parameter setting

[0077] The cold plate of the cryogenic pump is divided into 16 equal-area detection regions (4x4 grid); the weight coefficients in the temperature adjustment model are set according to experience = 0.6, = 0.4 ( + = 1); the temperature difference value preset range is set to [0.5K, 2.0K] according to experience; the cold plate state evaluation threshold is set to 0.6 according to experience, that is, when the cold plate state evaluation value Pb≥ 0.6, it is determined that the cold plate is in an abnormal state; the weight coefficients ai are set to = 0.5, = 0.3, = 0.2 (∑ = 1) according to experience; the standard temperature range of the environment is set to [290K, 300K] and the standard air exhaust speed range is set to [1000 L / s, 1200 L / s] according to experience.

[0078] The current cold plate temperature is measured to be 60K.

[0079] 2. Evaluation and adjustment according to the following steps:

[0080] S1. Calculate the cold plate state evaluation value Pb

[0081] In this embodiment, the total area of the detection region is divided into 16 regions, and the total area of the condensation layer accounts for 10 regions, so

[0082] The condensation layer area factor = 0.625;

[0083] ​The temperature difference detection results of each region in this embodiment show that the temperature differences of 12 regions are in the range of [0.5K, 2.0K], which are normal regions, and the temperature differences of 4 regions exceed the limit, and the temperature difference values are 2.3K, 2.5K, 0.3K and 0.2K, so:

[0084] Abnormal region factor ;

[0085] The temperature difference values 2.3K, 2.5K, 0.3K and 0.2K of the abnormal regions are compared with the two end point values 0.5K and 2.0K of the preset range of the temperature difference value, one end point value m closest to the temperature difference value is selected, and difference processing is performed on the temperature difference value, to obtain the temperature difference deviation values 0.3K, 0.5K, 0.2K and 0.3K, so the temperature difference factor is calculated according to the maximum temperature difference deviation value 0.5K , so:

[0086] Temperature difference factor ;

[0087] The calculated , , is substituted into the cold plate state evaluation value Pb to obtain:

[0088] ;

[0089] S2. State determination

[0090] Since , it is determined that the cold plate is in a normal state, and there is no need to adjust the temperature, and the process returns to step S1 to continue detection.

[0091] Abnormal scenario simulation

[0092] Suppose that changes occur in the monitoring, three abnormal regions are added, and the most serious temperature difference value increases to 3.0K, at this time the total abnormal region is 7, and the condensation layer area factor is unchanged, so:

[0093] Abnormal region factor ;

[0094] Temperature difference factor ;

[0095] ;

[0096] At this time , it is determined that the cold plate is still in a normal state, and there is no need to adjust the temperature, and the process returns to step S1 to continue detection.

[0097] Until a certain period, the number of abnormal regions increases to 10, the most serious temperature difference value is 3.2K, and the condensation layer area factor is unchanged, so:

[0098] abnormal region factor ;

[0099] temperature difference factor ;

[0100] ;

[0101] at this time , it is determined that the cold plate is in an abnormal state, and step S3 is performed to adjust the temperature.

[0102] S3. Adjusting the temperature

[0103] The current environment temperature of the cryogenic pump is obtained as 303K, which is compared with the two endpoint values 209K and 300K of the standard temperature range, and the endpoint value n=300K closest to the current environment temperature is selected to be processed by difference with the current environment temperature, and the environment temperature difference is 3K, then:

[0104] environment temperature evaluation value ;

[0105] The current pumping speed is obtained as 950 L / s, which is compared with the two endpoint values 1000 L / s and 1200 L / s of the standard pumping speed range, and the endpoint value o closest to the current pumping speed is selected to be processed by difference with the current pumping speed, and the pumping speed difference is 50 L / s, then:

[0106] cryogenic pump pumping speed evaluation value ;

[0107] cold plate temperature adjustment value :

[0108] ;

[0109] By controlling the power of the refrigerator in the cryogenic pump or adjusting the flow rate of liquid nitrogen, the cold plate temperature is reduced from the current temperature by 38.52K, and the monitoring is continued until , the normal state is restored.

[0110] As can be seen from the above examples, the regenerative heating method provided by the application has good feasibility for adjusting the cryogenic pump.

[0111] The above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modification, equivalent replacement and improvement made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A cryopump regenerative heating method, characterized by, According to the condensation layer area and the condensation layer temperature of the cold plate to be processed of the cryogenic pump, the state of the cold plate to be processed is evaluated, and when the cold plate to be processed is in an abnormal state, a cold plate temperature adjustment value is obtained The cold plate temperature is adjusted; Comprising the following steps: S1. Obtain the condensation layer area and condensation layer temperature of the cold plate to be processed, and calculate the cold plate state evaluation value according to the following formula According to the calculated cold plate state evaluation value, the state of the cold plate to be processed is evaluated: ； wherein is a condensation layer area factor, is an abnormal area factor, is a temperature difference factor, , , is a weight coefficient and ; S2. Compare the cold plate status evaluation value with a cold plate status evaluation threshold value, and when the cold plate status evaluation value exceeds the cold plate status evaluation threshold value, proceed to step S3, otherwise return to step S1. S3. Determine whether the cold plate is in an abnormal state or not, and when the cold plate is in an abnormal state, proceed to step S4, otherwise return to step S1. S4. Perform a cold plate status evaluation, and when the cold plate status evaluation value exceeds the cold plate status evaluation threshold value, proceed to step S5, otherwise return to step S1. S3. Obtain a cold plate temperature adjustment value according to the following temperature adjustment model and adjust the cold plate temperature: ； wherein, is the current temperature of the cold plate to be treated, is the ambient temperature evaluation value, is the cryopump evacuation speed evaluation value, , are weight coefficients, taken empirically, and .

2. A method of regenerative heating of a cryopump as defined in claim 1, characterized in that, Divide the cold plate to be processed into several detection areas according to area average, the sum of the areas of the cold plate in all detection areas is the total detection area, and the sum of the areas of the condensing layer on the cold plate in all detection areas is the total condensing layer area, then: Condensation layer area factor ​ Differentially process the condensing layer temperature and the cold plate temperature in each detection area to obtain a temperature difference value, compare the temperature difference value with a preset temperature difference value range, if the temperature difference value is within the preset temperature difference value range, mark the detection area as a normal area, otherwise, mark the detection area as an abnormal area, then: Abnormal region factor ​ Compare the temperature difference value of the abnormal area with two end point values of the preset temperature difference value range, select one end point value m closest to the temperature difference value and differentially process the temperature difference value to obtain a temperature difference deviation value, then: Temperature difference factor .

3. A method of regenerative heating of a cryopump as defined in claim 1, characterized in that, Obtain the current environment temperature of the cryogenic pump, compare the current environment temperature with two end point values of a standard temperature range, select one end point value n closest to the current environment temperature and differentially process the current environment temperature to obtain an environment temperature difference, then: Ambient temperature assessment value .

4. A method of regenerative heating of a cryopump as defined in claim 1, characterized in that, Obtain the current pumping speed of the cryogenic pump, compare the current pumping speed with two end point values of a standard pumping speed range, select one end point value o closest to the current pumping speed and differentially process the current pumping speed to obtain a pumping speed difference, then: Low temperature pump down speed evaluation value .

5. A method of regenerative heating of a cryopump as defined in claim 2, characterized in that, When there are multiple abnormal regions, the temperature difference factor is calculated using the temperature difference deviation value of the maximum value .

6. A cryogenic pump regeneration heating system for performing the cryogenic pump regeneration heating method according to any one of claims 1-5.

7. A chip storing a program for performing the cryogenic pump regeneration heating method according to any one of claims 1-5.

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