Diffusion pump control system and vacuum system for molecular beam epitaxy equipment

Abstract

The present invention relates to a diffusion pump control system applied to molecular beam epitaxy equipment, comprising a diffusion pump, a gate valve, a vacuum sensor and a temperature sensor. The air exhaust port of the diffusion pump is connected to the vacuum reaction chamber of the molecular beam epitaxy equipment. The diffusion pump has a front-stage vacuum pipeline, and the diffusion pump is connected to a mechanical pump through the front-stage vacuum pipeline; the gate valve is arranged between the vacuum reaction chamber and the diffusion pump; the vacuum sensor is arranged on the front-stage vacuum pipeline of the diffusion pump; the temperature sensor is arranged on the diffusion pump; when the signal collected by the vacuum sensor and / or the temperature sensor exceeds or is lower than the threshold value of each sensor when the diffusion pump is operating normally, the gate valve is triggered to close to prevent the oil of the diffusion pump from being back-drawn into the vacuum reaction chamber. The present invention overcomes the defect in the prior art that the medium oil is back-drawn into the vacuum reaction chamber, which has a fatal impact on the molecular beam epitaxy equipment and epitaxial materials.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum equipment, and in particular to a diffusion pump control system and a vacuum system applied to molecular beam epitaxy equipment. Background Art

[0002] Diffusion pumps are widely used in vacuum systems. Compared with cold pumps, diffusion pumps have advantages such as high pumping speed and no vibration in the high vacuum section. Therefore, they have great advantages when used in molecular beam epitaxy equipment (MBE) for fine epitaxial material growth. Conventional diffusion pumps only need to power the diffusion pump electric heating wire, and the medium oil in the diffusion pump can be heated by electricity to form an effective pumping speed when it reaches a certain temperature.

[0003] The diffusion pump requires silicone oil as the working medium. Once the diffusion pump has an abnormal pumping speed or stops running, the silicone oil may be pumped back into the vacuum reaction chamber of the molecular beam epitaxy (MBE) equipment. The diffusion pump oil backflow problem will have a fatal impact on the quality of epitaxial semiconductor materials and MBE equipment, resulting in huge economic losses. Therefore, in order to avoid the medium oil from being pumped back into the MBE vacuum reaction chamber, it is urgent to propose a diffusion pump control system for molecular beam epitaxy equipment. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the technical defect in the prior art that the medium oil is pumped back into the MBE vacuum reaction chamber, causing fatal effects on the molecular beam epitaxy equipment and epitaxial materials.

[0005] In order to solve the above technical problems, the present invention provides a diffusion pump control system applied to a molecular beam epitaxy device, comprising:

[0006] A diffusion pump, whose gas extraction port is connected to the vacuum reaction chamber of the molecular beam epitaxy equipment, the diffusion pump has a front-stage vacuum pipeline, and the diffusion pump is connected to the mechanical pump through the front-stage vacuum pipeline;

[0007] A gate valve, which is arranged between the vacuum reaction chamber and the diffusion pump;

[0008] A vacuum sensor is disposed on a front-stage vacuum pipeline of the diffusion pump, and the vacuum sensor is used to measure the vacuum value of the front-stage vacuum pipeline in real time;

[0009] A temperature sensor is disposed on the diffusion pump, and is used to measure the actual temperature of the diffusion pump in real time;

[0010] When the signal collected by the vacuum sensor and / or the temperature sensor exceeds or is lower than the threshold of each sensor when the diffusion pump is operating normally, the gate valve is triggered to close to prevent the oil in the diffusion pump from being pumped back into the vacuum reaction chamber.

[0011] In one embodiment of the present invention, an interlocking module is also included, which includes a diffusion pump interlocking unit, and the diffusion pump interlocking unit includes an overheating protection switch, a low-temperature emergency stop switch and a vacuum protection switch, wherein when the signal collected by the temperature sensor exceeds a set threshold, the overheating protection switch is triggered to switch the switch state; when the signal collected by the temperature sensor is lower than the set threshold, the low-temperature emergency stop switch is triggered to switch the switch state; when the signal collected by the vacuum sensor exceeds the set threshold, the vacuum protection switch is triggered to switch the switch state.

[0012] In one embodiment of the present invention, the interlock module further comprises a mechanical pump operation switch and a diffusion pump operation auxiliary relay contact, and the mechanical pump operation switch, the diffusion pump operation auxiliary relay contact and the diffusion pump interlock unit are connected in series.

[0013] In one embodiment of the present invention, a gate valve interlock bypass is further included, and both ends of the gate valve interlock bypass are connected to the interlock module.

[0014] In one embodiment of the present invention, it also includes a gate valve opening relay and a gate valve opening relay contact, the gate valve opening relay contact is commonly connected to the interlock module and the gate valve interlock bypass, and the gate valve opening relay contact is connected to the gate valve opening relay.

[0015] In one embodiment of the present invention, a gate valve opening switch is further included, and the gate valve opening switch is commonly connected to the interlocking module and the gate valve interlocking bypass.

[0016] In one embodiment of the present invention, a diffusion pump interlock bypass is further included, and both ends of the diffusion pump interlock bypass are connected to the diffusion pump interlock unit.

[0017] In one embodiment of the present invention, a flow sensor is further included. The diffusion pump has a cooling water pipeline. The flow sensor is arranged on the cooling water pipeline. The flow sensor and the mechanical pump constitute a pre-module. The pre-module is arranged at the front end of the diffusion pump interlock unit and the diffusion pump interlock bypass. The diffusion pump can only be started after the pre-module is running, and the pre-module cannot be bypassed.

[0018] In one embodiment of the present invention, it also includes a diffusion pump start-up auxiliary relay, a diffusion pump start-up auxiliary relay contact and a diffusion pump operation auxiliary relay, wherein the diffusion pump start-up auxiliary relay contact is commonly connected to the diffusion pump interlock unit and the diffusion pump interlock bypass, the diffusion pump start-up auxiliary relay contact is connected to the diffusion pump start-up auxiliary relay, the diffusion pump start-up auxiliary relay is connected to the diffusion pump operation auxiliary relay, and the diffusion pump operation auxiliary relay is connected to the diffusion pump operation auxiliary relay contact.

[0019] In addition, the present invention also provides a vacuum system, including a diffusion pump control system applied to a molecular beam epitaxy device as described above.

[0020] The above technical solution of the present invention has the following advantages compared with the prior art:

[0021] The diffusion pump control system and vacuum system applied to molecular beam epitaxy equipment described in the present invention integrate a vacuum sensor and a temperature sensor to monitor the operating status of the diffusion pump in real time. When the diffusion pump operates abnormally, the gate valve between the diffusion pump and the vacuum reaction chamber of the molecular beam epitaxy equipment is automatically closed, thereby preventing the medium oil from being pumped back into the vacuum reaction chamber, thereby protecting the vacuum reaction chamber and overcoming the defect in the prior art that the medium oil is pumped back into the vacuum reaction chamber and causing fatal effects on the molecular beam epitaxy equipment and epitaxial materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0023] Figure 1 The present invention provides a control block diagram of a diffusion pump control system applied to a molecular beam epitaxy device.

[0024] Figure 2 This is another control block diagram of a diffusion pump control system applied to a molecular beam epitaxy device proposed by the present invention.

[0025] Among them, the accompanying drawings are described as follows: 101, low temperature emergency stop switch; 102, overheat protection switch; 103, vacuum protection switch; 2, mechanical pump operation switch; 3, diffusion pump operation auxiliary relay contact; 4, gate valve interlock bypass; 401, gate valve interlock bypass switch; 5, gate valve opening relay; 6, gate valve opening relay contact; 7, gate valve opening switch; 8, gate valve stop switch; 9, diffusion pump interlock bypass; 901, diffusion pump interlock bypass switch, 10, flow trigger switch; 11, mechanical pump start switch; 12, diffusion pump start auxiliary relay; 13, diffusion pump start auxiliary relay contact; 14, diffusion pump operation auxiliary relay; 15, diffusion pump start switch; 16, diffusion pump stop switch; 17, vacuum solenoid valve operation relay; 18, vacuum solenoid valve opening switch; 19, vacuum solenoid valve operation relay contact a; 20, vacuum solenoid valve operation relay contact b. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0027] Reference Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a diffusion pump control system applied to molecular beam epitaxy equipment, including a diffusion pump, a gate valve, a vacuum sensor and a temperature sensor, the diffusion pump exhaust port is connected to the vacuum reaction chamber of the molecular beam epitaxy equipment, the diffusion pump has a fore-stage vacuum pipeline, and the diffusion pump is connected to a mechanical pump through the fore-stage vacuum pipeline; the gate valve is arranged between the vacuum reaction chamber and the diffusion pump; the vacuum sensor is arranged on the fore-stage vacuum pipeline of the diffusion pump, and the vacuum sensor is used to measure the vacuum value of the fore-stage vacuum pipeline in real time; the temperature sensor is arranged on the diffusion pump, and the temperature sensor is used to measure the actual temperature of the diffusion pump in real time; wherein, when the signal collected by the vacuum sensor and / or the temperature sensor exceeds or is lower than the set threshold value of each sensor when the diffusion pump is operating normally, the gate valve is triggered to close to prevent the oil in the diffusion pump from being back-drawn into the vacuum reaction chamber.

[0028] The diffusion pump control system applied to molecular beam epitaxy equipment described in the present invention integrates a vacuum sensor and a temperature sensor to monitor the operating status of the diffusion pump in real time. When the diffusion pump operates abnormally, the gate valve between the diffusion pump and the vacuum reaction chamber of the molecular beam epitaxy equipment is automatically closed, thereby preventing the medium oil from being pumped back into the vacuum reaction chamber, thereby protecting the vacuum reaction chamber and overcoming the defect in the prior art that the medium oil is pumped back into the vacuum reaction chamber and causing fatal effects on the molecular beam epitaxy equipment and epitaxial materials.

[0029] A diffusion pump control system for molecular beam epitaxy equipment provided by an embodiment of the present invention also includes an interlock module, the interlock module includes a diffusion pump interlock unit, the diffusion pump interlock unit includes an overheat protection switch 102, a low-temperature emergency stop switch 101 and a vacuum protection switch 103, wherein the above-mentioned overheat protection switch 102, the low-temperature emergency stop switch 101 and the vacuum protection switch 103 are connected in series, and the overheat protection switch 102, the low-temperature emergency stop switch 101 and the vacuum protection switch 103 are all in a closed state when the diffusion pump is operating normally, but when the signal collected by the temperature sensor exceeds the set threshold, it will trigger the overheat protection switch 102 to disconnect, and the diffusion pump will stop working at this time; similarly, when the signal collected by the temperature sensor is lower than the set threshold, it will trigger the low-temperature emergency stop switch 101 to disconnect, and the diffusion pump will stop working at this time; similarly, when the signal collected by the vacuum sensor exceeds the set threshold, it will trigger the vacuum protection switch 103 to disconnect, and the diffusion pump will stop working at this time.

[0030] In order to avoid the ambient temperature fluctuations and cause the diffusion pump to trigger the protection in error, two low-temperature thresholds are set for the working temperature of the diffusion pump, including the first threshold and the second threshold. As an example, the first threshold can be 20°C, and the second threshold can be 10°C, that is, when the actual temperature of the diffusion pump detected by the temperature sensor is lower than the set 20°C, an audible and visual alarm will be issued to remind the on-site staff to intervene in time to check the working status of the diffusion pump; when the actual temperature of the diffusion pump detected by the temperature sensor is lower than the set 10°C, the low-temperature emergency stop switch 101 will be triggered to disconnect, and the gate valve between the vacuum reaction chamber and the diffusion pump will be automatically closed immediately to protect the vacuum reaction chamber from the diffusion pump oil backflow pollution.

[0031] When the molecular beam epitaxy equipment is growing epitaxial materials, the vacuum value of the vacuum reaction chamber is constantly changing, which may cause the vacuum value of the vacuum pipeline between the diffusion pump and the front-stage mechanical pump to change dynamically. In order to avoid the normal dynamic change of the vacuum value causing the system to misjudge the protection, the vacuum value of the vacuum pipeline between the diffusion pump and the front-stage mechanical pump is set with two vacuum value thresholds, including the first vacuum value threshold and the second vacuum value threshold. As an example, the first vacuum value threshold can be 50mbar, and the second vacuum value threshold can be 100mbar. When the actual vacuum value detected by the vacuum sensor exceeds 50mbar, an audible and visual alarm will be issued to remind the on-site staff to check the working status of the diffusion pump; when the actual vacuum value detected by the vacuum sensor exceeds 100mbar, the vacuum protection switch 103 will be triggered to disconnect, and the gate valve between the vacuum reaction chamber and the diffusion pump will be automatically closed immediately to protect the vacuum reaction chamber from the diffusion pump oil backdraft pollution.

[0032] Furthermore, a diffusion pump control system for molecular beam epitaxy equipment provided by an embodiment of the present invention further includes a diffusion pump interlock bypass 9, and both ends of the diffusion pump interlock bypass 9 are connected to the diffusion pump interlock unit. As an example, the diffusion pump interlock bypass 9 of this embodiment includes a diffusion pump interlock bypass switch 901, that is, this embodiment designs two working states, and the interlock relationship of each sensor acquisition signal is bypassed by the diffusion pump interlock bypass switch 901, so that the diffusion pump can be freely started or stopped without being affected by the sensor signal, which is convenient for the inspection and maintenance of the diffusion pump control system.

[0033] In addition, a diffusion pump control system for molecular beam epitaxy equipment provided by an embodiment of the present invention further includes a flow sensor, the diffusion pump has a cooling water pipeline, the flow sensor is arranged on the cooling water pipeline, and the flow sensor and the mechanical pump constitute a pre-module, and the pre-module is arranged at the front end of the diffusion pump interlock unit and the diffusion pump interlock bypass 9. As an example, the flow sensor corresponds to the flow trigger switch 10, and the mechanical pump corresponds to the mechanical pump start switch 11. The mechanical pump start switch 11 of this embodiment refers to the button switch of the mechanical pump itself. When the mechanical pump start switch 11 is pressed, the mechanical pump starts, and when the mechanical pump start switch is disconnected, the mechanical pump stops working. In this embodiment, a pre-module is added to the start logic of the diffusion pump. The pre-module includes two pre-conditions, one is that the process cooling water flow is normal, and the other is that the front stage mechanical pump of the diffusion pump operates normally. Only when these two pre-conditions are met at the same time, the diffusion pump can be started, and these two pre-conditions cannot be bypassed, so that the operator can avoid mistakenly starting the diffusion pump when the front stage mechanical pump is not started or the cooling water is not passed, causing damage to the diffusion pump.

[0034] Next, a diffusion pump control system applied to a molecular beam epitaxy device provided by an embodiment of the present invention also includes a diffusion pump start switch 15, a diffusion pump start auxiliary relay 12, a diffusion pump start auxiliary relay contact 13 and a diffusion pump operation auxiliary relay 14, wherein the diffusion pump start switch 15 is jointly connected to the diffusion pump interlock unit and the diffusion pump interlock bypass 9, the diffusion pump start auxiliary relay contact 13 is jointly connected to the diffusion pump interlock unit and the diffusion pump interlock bypass 9, the diffusion pump start auxiliary relay contact 13 is connected to the diffusion pump start auxiliary relay 12, the diffusion pump start auxiliary relay 12 is connected to the diffusion pump operation auxiliary relay 14, and the diffusion pump operation auxiliary relay 14 is connected to the diffusion pump operation auxiliary relay contact 3.

[0035] In actual operation, when the process cooling water flow is normal, the front-stage mechanical pump of the diffusion pump operates normally, and the signals collected by the temperature sensor and the vacuum sensor are normal, the flow trigger switch 10, the mechanical pump start switch 11, the low-temperature emergency stop switch 101, the overheat protection switch 102 and the vacuum protection switch 103 are all closed. When the diffusion pump start switch 15 is pressed, the diffusion pump start auxiliary relay contact 13 is energized and closed, the diffusion pump start auxiliary relay 12 is turned on, and the diffusion pump operation auxiliary relay 14 is turned on at the same time. During the operation of the diffusion pump, the diffusion pump operation auxiliary relay 14 is always in the on state to display the working status of the diffusion pump.

[0036] During the operation of the above-mentioned diffusion pump, if the process cooling water flow is abnormal, or the mechanical pump before the diffusion pump is abnormal, or the signal collected by the vacuum sensor is abnormal, or the signal collected by the temperature sensor is abnormal, the diffusion pump stops working and immediately triggers the gate valve to close to prevent the oil of the diffusion pump from being back-drawn into the vacuum reaction chamber. It should be emphasized that the judgment conditions for the abnormal signals collected by the vacuum sensor and the temperature sensor have been elaborated in detail in the above content, and the diffusion pump will only be triggered to stop working if it does not meet the specific threshold range, and this embodiment will not be repeated here.

[0037] Of course, the diffusion pump control system for molecular beam epitaxy equipment provided by the embodiment of the present invention also includes a diffusion pump stop switch 16, which can stop the diffusion pump from working, thereby facilitating the operation, inspection and maintenance of the diffusion pump control system.

[0038] Next, the interlocking module further includes a mechanical pump operation switch 2 and a diffusion pump operation auxiliary relay contact 3, and the mechanical pump operation switch 2, the diffusion pump operation auxiliary relay contact 3 and the diffusion pump interlocking unit are connected in series. The mechanical pump operation switch of this embodiment corresponds to the operation state of the mechanical pump itself. When the mechanical pump is in operation, the mechanical pump operation switch 2 is in a closed state at this time. When the mechanical pump stops working, the mechanical pump operation switch 2 is disconnected; similarly, the diffusion pump operation auxiliary relay contact 3 of this embodiment corresponds to the diffusion pump operation auxiliary relay 14. When the diffusion pump operation auxiliary relay 14 is in a conducting state, the diffusion pump operation auxiliary relay contact 3 is closed.

[0039] Next, a diffusion pump control system applied to a molecular beam epitaxy device provided by an embodiment of the present invention also includes a gate valve interlock bypass 4, and both ends of the gate valve interlock bypass 4 are connected to the interlock module. As an example, the gate valve interlock bypass 4 of this embodiment includes a gate valve interlock bypass switch 401, that is, this embodiment is designed with two working states, and the interlocking relationship between the mechanical pump operation switch 2, the diffusion pump operation auxiliary relay contact 3 and the diffusion pump interlock unit is bypassed by the gate valve interlock bypass 4, so that the gate valve can be freely started or stopped without being affected by it, which is convenient for the inspection and maintenance of the diffusion pump control system.

[0040] Next, a diffusion pump control system applied to a molecular beam epitaxy device provided by an embodiment of the present invention also includes a gate valve opening relay 5 and a gate valve opening relay contact 6, the gate valve opening relay contact 6 is jointly connected to the interlock module and the gate valve interlock bypass 4, and the gate valve opening relay contact 6 is connected to the gate valve opening relay 5.

[0041] In actual operation, when the diffusion pump operates normally, the gate valve between the diffusion pump and the vacuum reaction chamber is in an open state. At this time, the gate valve opening relay contact 6 is energized and closed, and the gate valve opening relay 5 is turned on.

[0042] During the operation of the above-mentioned diffusion pump, if any of the diffusion pump operation auxiliary relay contacts 3, the mechanical pump operation switch 2, the low-temperature emergency stop switch 101, the overheating protection switch 102, or the vacuum protection switch 103 is disconnected, the gate valve will be immediately triggered to close to prevent the oil in the diffusion pump from being back-drawn into the vacuum reaction chamber.

[0043] Of course, a diffusion pump control system for molecular beam epitaxy equipment provided by an embodiment of the present invention also includes a gate valve opening switch 7, and the gate valve opening switch 7 is jointly connected to the interlock module and the gate valve interlock bypass 4. The gate valve can be opened by the gate valve opening switch 7, which facilitates the operation, inspection and maintenance of the gate valve.

[0044] A diffusion pump control system for molecular beam epitaxy equipment provided by an embodiment of the present invention also includes a gate valve stop switch 8, which is in a normally closed state. When the diffusion pump is in operation, the gate valve stop switch 8 is in a closed state. The gate valve stop switch can be used to stop the gate valve from working, thereby facilitating the operation, inspection and maintenance of the gate valve.

[0045] Next, a diffusion pump control system applied to molecular beam epitaxy equipment provided by an embodiment of the present invention also includes a vacuum solenoid valve, which is arranged at the exhaust port of the diffusion pump. The vacuum solenoid valve can be started and stopped synchronously with the diffusion pump. On the one hand, it can prevent the diffusion pump from back-pumping the previous mechanical pump after the diffusion pump stops running. On the other hand, it can ensure that the diffusion pump can obtain primary vacuum before starting.

[0046] As an example, the vacuum solenoid valve corresponds to the vacuum solenoid valve operation relay 17, and the vacuum solenoid valve operation relay 17 has a vacuum solenoid valve operation relay contact a19 and a vacuum solenoid valve operation relay contact b20. The vacuum solenoid valve operation relay contact a19 is a pair of normally open contacts of the vacuum solenoid valve operation relay 17, and the vacuum solenoid valve operation relay contact b20 is a pair of normally closed contacts of the vacuum solenoid valve operation relay 17. When the diffusion pump is running, that is, the diffusion pump operation auxiliary relay 14 is energized, at this time, the vacuum solenoid valve operation relay contact a19 is energized and closed, that is, the vacuum solenoid valve starts to work, and at the same time, the vacuum solenoid valve operation relay contact b20 is energized and disconnected. Of course, the vacuum solenoid valve can be opened manually independently, for example, the vacuum solenoid valve can be opened by the vacuum solenoid valve opening switch 18.

[0047] Corresponding to the above-mentioned embodiment of a diffusion pump control system applied to molecular beam epitaxy equipment, the present invention also provides a vacuum system, including a diffusion pump control system applied to molecular beam epitaxy equipment as described above, and the vacuum system has all the beneficial effects of the above-mentioned diffusion pump control system applied to molecular beam epitaxy equipment, which will not be elaborated here by the present invention.

[0048] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A diffusion pump control system for molecular beam epitaxy equipment, characterized in that: include: A diffusion pump, whose gas extraction port is connected to the vacuum reaction chamber of the molecular beam epitaxy equipment, the diffusion pump has a front-stage vacuum pipeline, and the diffusion pump is connected to the mechanical pump through the front-stage vacuum pipeline; A gate valve, which is arranged between the vacuum reaction chamber and the diffusion pump; A vacuum sensor is disposed on a front-stage vacuum pipeline of the diffusion pump, and the vacuum sensor is used to measure the vacuum value of the front-stage vacuum pipeline in real time; A temperature sensor is disposed on the diffusion pump, and is used to measure the actual temperature of the diffusion pump in real time; An interlock module, wherein the interlock module includes a diffusion pump interlock unit, a mechanical pump operation switch and a diffusion pump operation auxiliary relay contact, wherein the diffusion pump interlock unit includes an overheat protection switch, a low-temperature emergency stop switch and a vacuum protection switch; wherein, when the signal collected by the vacuum sensor and / or the temperature sensor exceeds or is lower than the threshold value of each sensor set during normal operation of the diffusion pump, the gate valve is triggered to close to prevent the oil of the diffusion pump from being back-drawn into the vacuum reaction chamber; when the signal collected by the temperature sensor exceeds the set threshold value, the overheat protection switch is triggered to switch the switch state; the temperature of the diffusion pump includes a first threshold value and a second threshold value, wherein the second threshold value is less than the first threshold value, When the signal collected by the temperature sensor is lower than the first threshold, an audible and visual alarm is issued; when the signal collected by the temperature sensor is lower than the second threshold, the low-temperature emergency stop switch is triggered to switch the switch state; the vacuum value of the front-stage vacuum pipeline includes a first vacuum value threshold and a second vacuum value threshold, the first vacuum value threshold is less than the second vacuum value threshold, and when the signal collected by the vacuum sensor exceeds the first vacuum value threshold, an audible and visual alarm is issued; when the signal collected by the vacuum sensor exceeds the second vacuum value threshold, the vacuum protection switch is triggered to switch the switch state; the mechanical pump operation switch, the diffusion pump operation auxiliary relay contact and the diffusion pump interlocking unit are connected in series; It also includes a gate valve interlock bypass, a gate valve opening relay, a gate valve opening relay contact, a gate valve opening switch, a diffusion pump interlock bypass, a diffusion pump start-up auxiliary relay, a flow sensor, a diffusion pump start-up auxiliary relay contact and a diffusion pump operation auxiliary relay; the two ends of the gate valve interlock bypass are connected to the interlock module; the gate valve opening relay contact is commonly connected to the interlock module and the gate valve interlock bypass, and the gate valve opening relay contact is connected to the gate valve opening relay; the gate valve opening switch is commonly connected to the interlock module and the gate valve interlock bypass; the two ends of the diffusion pump interlock bypass are connected to the diffusion pump interlock unit; the diffusion pump has a cooling water The flow sensor is arranged on the cooling water pipeline, and the flow sensor and the mechanical pump constitute a pre-module, the pre-module is arranged at the front end of the diffusion pump interlock unit and the diffusion pump interlock bypass, the diffusion pump can be started only after the pre-module is running, and the pre-module cannot be bypassed; the diffusion pump start auxiliary relay contacts are commonly connected to the diffusion pump interlock unit and the diffusion pump interlock bypass, the diffusion pump start auxiliary relay contacts are connected to the diffusion pump start auxiliary relay, the diffusion pump start auxiliary relay is connected to the diffusion pump operation auxiliary relay, and the diffusion pump operation auxiliary relay is connected to the diffusion pump operation auxiliary relay contacts.

2. A vacuum system, characterized in that: It comprises a diffusion pump control system applied to molecular beam epitaxy equipment as described in claim 1.

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