Power-off protection system and semiconductor process equipment

Abstract

The utility model provides a power-off protection system and semiconductor process equipment. A power-off detection unit comprising a voltage comparison circuit and a divider resistor is used for judging whether an equipment circuit is powered off or not; specifically, a voltage comparison circuit is used for comparing the voltage of a divider resistor with the voltage of a conversion unit connected with a power supply, so that the characteristic that the voltage of the divider resistor is rapidly reduced when the power supply is powered off and the voltage of the conversion unit is slowly reduced due to capacitive reactance and inductive reactance is utilized to timely judge that an equipment circuit is in a power-off state; and the charging and discharging unit is used for discharging when the voltage comparison circuit judges that the equipment circuit is in the power-off state so as to timely supply power to the electricity-needing device when the power supply is powered off, so that long-time loss of control on the electricity-needing device in the semiconductor process equipment is avoided, and safety accidents are further avoided.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of semiconductor process equipment, specifically relates to a power-off protection system and semiconductor process equipment. BACKGROUND

[0002] The semiconductor process equipment is usually provided with pressure control type valves and mass flow meters and other components to control the air intake of the process chamber. However, when the semiconductor process equipment is suddenly powered off due to external factors, the valves and mass flow meters cannot work normally, and thus cannot transmit their state signals to the general control equipment. Correspondingly, the general control equipment cannot obtain the real-time state of the valves and mass flow meters, and thus is prone to cause the equipment to malfunction, and thus cause other components in the overall equipment to be damaged, which is likely to cause a safety accident. SUMMARY

[0003] The utility model at least partially solves the problem that the existing semiconductor process equipment loses control over valve type components when powered off, and provides a power-off protection system and semiconductor process equipment.

[0004] The utility model embodiment provides a power-off protection system for performing power-off protection on the equipment circuit in the semiconductor process equipment.

[0005] The conversion unit is connected with the power supply in the equipment circuit and is used to convert the voltage output by the power supply into a specified voltage. The conversion unit includes at least one capacitor and / or at least one inductor.

[0006] The charge and discharge unit has a receiving end connected with the power supply and is used to charge when the equipment circuit is in a power supply state. The output end of the charge and discharge unit is connected with the electrical device in the equipment circuit.

[0007] The power-off detection unit includes a voltage comparison circuit and a voltage dividing resistor. The voltage comparison circuit has two receiving ends, one of which is connected with the conversion unit in series, and the other of which is connected with the voltage dividing resistor in series. The voltage dividing resistor is also connected with the power supply in series. The voltage comparison circuit is used to compare the voltage of the conversion unit with the voltage of the voltage dividing resistor, and determine whether the equipment circuit is in a power-off state according to the comparison result.

[0008] The charge and discharge unit is also used to discharge when the voltage comparison circuit determines that the equipment circuit is in a power-off state.

[0009] Optionally, the power-off protection system further includes a signal processing unit. The signal processing unit is connected with the output end of the voltage comparison circuit and the charge and discharge unit, respectively.

[0010] The voltage comparison circuit is further configured to send a first signal to the signal processing unit when determining that the device circuit is in a power-off state; and the signal processing unit is configured to send a second signal to the charge-discharge unit to control the charge-discharge unit to discharge when receiving the first signal.

[0011] Optionally, the powered device in the device circuit includes a valve device.

[0012] The power-off protection system further includes an interlocking unit, which is connected to an output end of the charge-discharge unit and a control end of the valve device respectively; and the interlocking unit is configured to send a third signal to the valve device to control the valve device to switch to a preset safe state when the charge-discharge unit is powered.

[0013] Optionally, the interlocking unit is connected to the conversion unit to connect the output end of the charge-discharge unit through the conversion unit.

[0014] Optionally, the charge-discharge unit includes an energy storage device, a charging circuit, and a discharge control circuit.

[0015] The energy storage device is configured to store electric energy.

[0016] The charging circuit is connected to the energy storage device and the power supply respectively, and is configured to transmit electric energy output by the power supply to the energy storage device.

[0017] The discharge control circuit is connected to the energy storage device and the signal processing unit respectively; and the discharge control circuit is configured to control the energy storage device to discharge when receiving the second signal.

[0018] Optionally, the energy storage device includes a battery or a super capacitor.

[0019] Optionally, the voltage comparison circuit includes a first voltage dividing circuit, a second voltage dividing circuit, a voltage comparator, and a signal output circuit.

[0020] The voltage comparator has two signal input ends and one signal output end; the first voltage dividing circuit is connected to the voltage dividing resistor and one signal input end of the voltage comparator respectively; and the second voltage dividing circuit is connected to the conversion unit and the other signal input end of the voltage comparator respectively.

[0021] The signal output circuit is connected to the signal output end of the voltage comparator and the signal processing unit respectively.

[0022] The first voltage dividing circuit and the second voltage dividing circuit are both used for reducing the received voltage in a specified ratio; and the voltage comparator is used for comparing the voltage received by two signal input ends and outputting the corresponding comparison result through a signal output end.

[0023] Optionally, the first voltage dividing circuit comprises a first diode, a first resistor and a first voltage stabilizing unit; the first diode and the first resistor are connected in series between the voltage dividing resistor and one signal input end of the voltage comparator; one end of the first voltage stabilizing unit is connected in the first voltage dividing circuit, and the other end is grounded.

[0024] The second voltage dividing circuit comprises a second resistor and a second voltage stabilizing unit; the second resistor is connected in series between the converting unit and the other signal input end of the voltage comparator; one end of the second voltage stabilizing unit is connected in the second voltage dividing circuit, and the other end is grounded.

[0025] As another technical solution, the utility model also provides a semiconductor process equipment, it includes a plurality of need electrical device, equipment circuit and the power-off protection system as described above, wherein,

[0026] The equipment circuit is connected with a plurality of the need electrical device, is used for sending control signal and power supply to corresponding the need electrical device;

[0027] The power-off protection system is connected with the equipment circuit, is used for sending control signal or power supply to the need electrical device when the equipment circuit occurs power-off.

[0028] Optionally, the semiconductor process equipment comprises a process chamber; a plurality of the need electrical device comprises an electrically controlled valve and a mass flow meter;

[0029] The electrically controlled valve and the mass flow meter are connected with the air inlet of the process chamber, are used for controlling the air intake of the process chamber;

[0030] The power-off protection system is used for sending closing signal to the electrically controlled valve and the mass flow meter when the equipment circuit occurs power-off, so that the process chamber stops air intake.

[0031] The utility model has the following beneficial effects:

[0032] The power-off protection system provided by the embodiment of the utility model, including conversion unit, charge and discharge unit and power-off detection unit, wherein, the power voltage in the equipment circuit of the semiconductor process equipment is converted into specified voltage by the conversion unit, the receiving end of the charge and discharge unit is connected with the power supply, the output end is connected with the power-required device in the equipment circuit, and is used for charging when power supply and supplying power when power-off, the power-off detection unit includes voltage comparison circuit and voltage dividing resistor, the voltage comparison circuit has two receiving ends, one of which is connected with the conversion unit in series, and the other is connected with the voltage dividing resistor in series, the voltage dividing resistor is also connected with the power supply in series, because the voltage dividing resistor is pure resistance device, and the conversion unit includes capacitor and / or inductor, therefore, the voltage of the voltage dividing resistor will rapidly decrease in the moment of power-off, and the voltage of the conversion unit will slowly decrease because of the existence of capacitive reactance and / or inductive reactance, based on this, the voltage comparison circuit can judge whether the equipment circuit is in power-off state according to the comparison result by comparing the voltage of the conversion unit with the voltage of the voltage dividing resistor, and the charge and discharge unit is also used for discharging when the voltage comparison circuit judges that the equipment circuit is in power-off state, so as to quickly respond when the power supply is power-off, avoid losing the control of the power-required device in the semiconductor process equipment for a long time, and further avoid the occurrence of safety accidents. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The schematic diagram of the power-off protection system provided by the embodiment of the utility model;

[0034] Figure 2 The schematic diagram of the power-off detection unit and other units connected therewith provided by the embodiment of the utility model;

[0035] Figure 3 The schematic diagram of the power-off detection unit provided by the embodiment of the utility model. DETAILED DESCRIPTION

[0036] In order to make the skilled in the art better understand the technical scheme of the utility model, the utility model is described in further detail below in combination with the drawings and specific embodiments.

[0037] It can be understood that the specific embodiments and drawings described herein are only used to explain the utility model, and not limit the utility model.

[0038] It can be understood that the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

[0039] It can be understood that, for the convenience of description, only the parts related to the embodiments of the utility model are shown in the drawings of the utility model, and the parts irrelevant to the embodiments of the utility model are not shown in the drawings.

[0040] It can be understood that the functions and steps marked in the flowcharts and block diagrams of the embodiments of the present application can occur in an order different from that marked in the drawings without conflict.

[0041] It can be understood that the above embodiments are only exemplary embodiments adopted for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

[0042] The semiconductor process equipment usually comprises a process chamber for performing a process, and gas inlet and outlet pipelines in communication with the process chamber, and a plurality of pressure control valves are arranged in the gas inlet and outlet pipelines to control the gas inlet and outlet states of the process chamber and the specific gas inlet and outlet amounts. The pressure control valves are usually electrically controlled valve devices, so that the opening and closing of the plurality of pressure control valves arranged in the gas inlet and outlet pipelines can be controlled by sending electric signals by the general control machine, and the electric signals emitted by the valves can be received by the general control machine to confirm whether each valve is in an open state or a closed state.

[0043] Moreover, after the semiconductor process equipment is suddenly powered off due to external factors, the valves lose control and cannot work normally, which easily leads to the problem of continuous gas inlet or continuous gas outlet of the process chamber, and further leads to the problem that the process chamber may have an excessively high internal gas pressure or process gas leakage, and even a safety accident may occur. Moreover, due to the power failure, the valves cannot transmit the electric signals of their own states to the general control machine, and further the general control machine cannot obtain the real-time states of the valves, and further easily leads to the misoperation of the general control machine in controlling the plurality of valves after the power is restored, thereby easily leading to the damage of other components in the semiconductor process equipment, and easily causing a safety accident.

[0044] In order to solve the above technical problems, the embodiment provides a power failure protection system applied to semiconductor process equipment, which is used for performing power failure protection on equipment circuits in the semiconductor process equipment. Figure 1 As shown in the figure, the power failure protection system comprises a conversion unit 1, a charge and discharge unit 2, and a power failure detection unit 3.

[0045] The conversion unit 1 is connected with a power supply 4 in the equipment circuits, and is used for converting the voltage output by the power supply 4 into a specified voltage; for example, the power supply 4 is a direct current voltage source and outputs a voltage of 24V, and the conversion unit 1 is used for converting the voltage output by the power supply 4 into a direct current voltage of 3.3V. The conversion unit 1 comprises at least one capacitor and / or at least one inductor.

[0046] The charging and discharging unit 2 has a receiving end for charging and an output end for discharging; specifically, the receiving end of the charging and discharging unit 2 is connected with the power supply 4 for charging when the device circuit is in a power supply state; the output end of the charging and discharging unit 2 is connected with the power-consuming devices in the device circuit, specifically, the power-consuming devices are, for example, the controller of the pressure control type valve and the stepping motor or servo motor for driving the valve plate to rotate.

[0047] The power-off detection unit 3 is used for detecting whether the device circuit is powered off. Specifically, as shown in Figure 2 , the power-off detection unit 3 includes a voltage comparison circuit 31 and a voltage dividing resistor 32; the voltage comparison circuit 31 has two receiving ends, one of which is connected in series with the conversion unit 1, and the other of which is connected in series with the voltage dividing resistor 32; the voltage dividing resistor 32 is also connected in series with the power supply 4.

[0048] Since the voltage dividing resistor 32 is a pure resistive device, and the conversion unit 1 includes a capacitor and / or an inductor, when the power supply 4 is turned on, the voltage dividing resistor 32 will have a certain voltage due to being connected in series with the power supply 4, and the conversion unit 1 will be in a charging state due to the presence of capacitive reactance and / or inductive reactance, and then the voltage of the conversion unit 1 will slowly rise until the charging is completed; and at the moment when the power supply 4 is powered off, since the voltage dividing resistor 32 is a pure resistive element, the voltage of the voltage dividing resistor 32 will instantaneously drop to 0, and the voltage of the conversion unit 1 will slowly decrease due to the presence of capacitive reactance and / or inductive reactance, so at the moment when the device circuit is powered off and for a period of time thereafter, the voltage corresponding to the conversion unit 1 collected by the voltage comparison circuit 31 will be greater than the voltage corresponding to the voltage dividing resistor 32. Based on this, the voltage comparison circuit 31 in the embodiment is used to compare the voltage of the conversion unit 1 with the voltage of the voltage dividing resistor 32, and determine whether the device circuit is in a power-off state according to the comparison result; for example, if the comparison result is that the voltage corresponding to the conversion unit 1 is greater than the voltage corresponding to the voltage dividing resistor 32, it is determined that the device circuit is in a power-off state, and the device circuit is determined to be in a power-off state in time. Moreover, the charging and discharging unit 2 is also used to discharge when the voltage comparison circuit 31 determines that the device circuit is in a power-off state, so as to quickly respond when the power supply 4 is powered off, avoid losing control of the power-consuming devices in the semiconductor process equipment for a long time, and thus avoid the occurrence of safety accidents; for example, the air inlet valve can be closed in time to avoid the process chamber continuously taking in air and the pressure being too high, the air outlet valve can be closed in time to avoid process gas leakage, and the controller of the valve can be powered to enable it to send its own state signal to the master control machine, so that the master control machine obtains the real-time state of the valve in time, and thus avoids the valve from being controlled to move incorrectly after the power is restored.

[0049] In some embodiments, as Figure 1As shown, the power-off protection system further comprises a signal processing unit 5. The signal processing unit 5 is connected with the output end of the voltage comparison circuit 31 and the charge-discharge unit 2 respectively. The voltage comparison circuit 31 is further configured to send a first signal to the signal processing unit 5 when determining that the device circuit is in a power-off state; and the signal processing unit 5 is configured to send a second signal to the charge-discharge unit 2 to control the charge-discharge unit 2 to discharge when receiving the first signal.

[0050] For example, the first signal and the second signal can be high-level signals or low-level signals.

[0051] For example, the signal processing unit 5 can be a microcontroller unit (MCU), which has simple structure, fast response, is suitable for simple signal processing, and has low cost.

[0052] In some embodiments, the powered devices in the device circuit include valve devices, such as electrically controlled valves, mass flow meters, etc. The power-off protection system further comprises an interlocking unit 6. The interlocking unit 6 is connected with the output end of the charge-discharge unit 2 and the control end of the valve device respectively. The interlocking unit 6 is configured to send a third signal to the valve device under the power supply of the charge-discharge unit 2 to control the valve device to switch to a preset safe state. Preferably, the interlocking unit 6 is an interlocking circuit, and correspondingly, the third signal can be a high-level signal or a low-level signal. After the interlocking unit 6 sends the third signal to the valve device, the valve device can switch and maintain the preset safe state until the interlocking unit 6 is reset, i.e., the end connected with the valve device of the interlocking unit 6 is switched from high level to low level or from low level to high level. In this way, the power required to control the valve device can be reduced, and the power consumption of the charge-discharge unit 2 can be slowed down, thereby giving the operator time to repair the device circuit.

[0053] It should be noted that the preset safety state refers to the state of the valve device when the power supply 4 is unexpectedly powered off, which can ensure that other components in the semiconductor process equipment will not be overloaded or damaged, thereby avoiding safety accidents and equipment damage. Specifically, the preset safety state can be set according to the specific use conditions of the semiconductor process equipment and the actual application conditions of the valve device in the semiconductor process equipment, and the preset safety state should be set before the valve device normally works, for example, during the debugging stage. For example, the preset safety state of the plurality of gas inlet valves arranged in the gas inlet pipeline of the process chamber is a full-closed state, and the preset safety state of the mass flow meter arranged in the gas inlet pipeline is also a full-closed state, so as to stop the process gas from being introduced into the process chamber in time, and avoid the pressure of the process chamber from being too high due to continuous gas inlet; for another example, the preset safety state of the plurality of exhaust valves arranged in the gas outlet pipeline of the process chamber is a full-closed state, so as to avoid process gas leakage.

[0054] In some embodiments, the interlocking unit 6 is connected with the conversion unit 1 to connect the output end of the charge-discharge unit 2 through the conversion unit 1, so as to supply power to the interlocking unit 6 by the charge-discharge unit 2, and provide power for the interlocking unit 6 to send the third signal.

[0055] In some embodiments, the charge-discharge unit 2 includes an energy storage device 21, a charging circuit 22, and a discharge control circuit 23. The energy storage device 21 is used to store power; specifically, the energy storage device 21 stores power at least to meet the power required by the interlocking unit 6 to send the third signal, the power required to drive the valve plate of the valve device to move, and the power required by the signal processing unit 5 to process and send signals. The charging circuit 22 is connected with the energy storage device 21 and the power supply 4 respectively, and is used to transmit the power output by the power supply 4 to the energy storage device 21.

[0056] The discharge control circuit 23 is connected with the energy storage device 21 and the signal processing unit 5 respectively; the discharge control circuit 23 is used to control the energy storage device 21 to discharge when receiving the second signal.

[0057] For example, the discharge control circuit 23 controls the energy storage device 21 to discharge by sending a fourth signal to the energy storage device 21. In this case, the energy storage device 21 also needs to store power to meet the power required by the discharge control circuit 23 to send the fourth signal.

[0058] In some embodiments, the energy storage device 21 includes a battery or a super capacitor.

[0059] For example, the conversion unit 1 can be a DC / DC conversion circuit, and is used to step down the DC power output from the energy storage device 21 and the DC power output from the power supply 4, so that the supply voltage delivered to the discharge control circuit 23, the interlock unit 6 and the signal processing unit 5 reaches a suitable voltage value.

[0060] In some embodiments, such as Figure 3 As shown, the voltage comparison circuit 31 includes: a first voltage divider circuit 311, a second voltage divider circuit 312, a voltage comparator 313, and a signal output circuit 314. The voltage comparator 313 has two signal input terminals and one signal output terminal. The first voltage divider circuit 311 is connected to the voltage divider resistor 32 and one signal input terminal of the voltage comparator 313, respectively. The second voltage divider circuit 312 is connected to the conversion unit 1 and the other signal input terminal of the voltage comparator 313, respectively. Both the first voltage divider circuit 311 and the second voltage divider circuit 312 are used to reduce the received voltage by a specified ratio, i.e., to perform voltage division, so that the voltages supplied to the two signal input terminals of the voltage comparator 313 meet the operating voltage of the voltage comparator 313, thus preventing damage to the voltage comparator 313. The voltage comparator 313 is used to compare the voltages received at the two signal input terminals and outputs the corresponding comparison result through the signal output terminal. The signal output circuit 314 is connected to the signal output terminal of the voltage comparator 313 and the signal processing unit 5, respectively, to send the comparison result to the signal processing unit 5.

[0061] Preferably, the comparison result output by the signal output terminal can be output in the form of a low-level signal and a high-level signal. For example, a low-level signal indicates that the voltage of the voltage divider resistor 32 after voltage division is greater than or equal to the output voltage of the power supply 4 after voltage division, and a high-level signal indicates that the voltage of the voltage divider resistor 32 after voltage division is less than the output voltage of the power supply 4 after voltage division.

[0062] like Figure 3As shown, in some specific embodiments, the first voltage divider circuit 311 includes a first diode D1, a first resistor R1, and a first voltage regulator unit 3111. The first diode D1 and the first resistor R1 are connected in series between the voltage divider resistor 32 and one signal input terminal of the voltage comparator 313. The first diode D1 can stabilize the voltage output by the first voltage divider circuit 311 using its own voltage drop. The first resistor R1 can share the voltage received from the voltage divider resistor 32 using its own resistance value, so that the signal voltage received by one signal input terminal of the voltage comparator 313 is not too high. The first voltage regulator unit 3111 can absorb excessively high voltage when there are voltage fluctuations in the first voltage divider circuit 311, thereby stabilizing the voltage signal received by the voltage comparator 313. This stabilizes the voltage signal acquired by the voltage comparator 313 corresponding to the voltage divider resistor 32 when the power supply 4 is turned on. The second voltage divider circuit 312 includes a second resistor R2 and a second voltage regulator unit 3121. The second resistor R2 is connected in series between the conversion unit 1 and the other signal input terminal of the voltage comparator 313. The second resistor R2 can share the voltage received from the conversion unit 1 using its own resistance, ensuring that the signal voltage received by the other signal input terminal of the voltage comparator 313 is not too high. One end of the second voltage regulator unit 3121 is connected in series in the second voltage divider circuit 312, and the other end is grounded. The second voltage regulator unit 3121 can absorb excessive voltage fluctuations in the second voltage divider circuit 312, thereby stabilizing the voltage signal received by the voltage comparator 313. This ensures that the voltage signal acquired by the voltage comparator 313 corresponding to the conversion unit 1 remains stable when the power supply 4 is turned on. Thus, by ensuring a stable voltage signal acquired by the voltage comparator 313 when the power supply 4 is turned on, misjudgments by the voltage comparator circuit 31 due to voltage fluctuations can be avoided, thereby preventing the charging / discharging unit 2 from accidentally turning on.

[0063] For example, such as Figure 3 As shown, the first voltage regulator unit 3111 includes a first capacitor C1 and a third resistor R3; one end of the first capacitor C1 is connected in series with the first resistor R1, and the other end is grounded, so as to reduce voltage fluctuations in the first voltage divider circuit 311 by utilizing the filtering characteristics of the capacitor; the third resistor R3 is connected in parallel across the first capacitor C1. The second voltage regulator unit 3121 includes a second capacitor C2 and a fourth resistor R4; one end of the second capacitor C2 is connected in series with the second resistor R2, and the other end is grounded, so as to reduce voltage fluctuations in the second voltage divider circuit 312 by utilizing the filtering characteristics of the capacitor; the fourth resistor R4 is connected in parallel across the second capacitor C2.

[0064] As another technical solution, the embodiment further provides a semiconductor process equipment, which comprises a plurality of electrical devices, an equipment circuit and the power-off protection system. The equipment circuit is connected with the plurality of electrical devices, and is configured to send control signals to the corresponding electrical devices and supply power to the corresponding electrical devices. The power-off protection system is connected with the equipment circuit, and is configured to send control signals or supply power to the electrical devices when the equipment circuit is powered off.

[0065] In some embodiments, the semiconductor process equipment comprises a process chamber; the plurality of electrical devices comprises an electrically controlled valve and a mass flow meter. The electrically controlled valve and the mass flow meter are connected with an air inlet and an air outlet of the process chamber, and are configured to control the air intake and air exhaust of the process chamber. The power-off protection system is configured to send a closing signal to the electrically controlled valve and the mass flow meter when the equipment circuit is powered off, so as to stop the air intake and air exhaust of the process chamber, thereby avoiding the continuous air intake of the process chamber to cause the chamber pressure to be too high, and avoiding the process gas to be leaked.

[0066] For example, the electrical devices further comprise a plurality of detection devices and process devices participating in the semiconductor process. It should be noted that if the power-off protection system also needs to send control signals or supply power to these electrical devices, the power storage capacity of the charging and discharging unit 2 of the power-off protection system needs to be adaptively improved.

[0067] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

Claims

1. A power-off protection system for providing power-off protection to a device circuit in a semiconductor process equipment; characterized by, The application relates to a power-off protection system for a device circuit, which comprises the following parts: a conversion unit connected with a power supply in the device circuit, used for converting the voltage output by the power supply into a specified voltage; the conversion unit comprises at least one capacitor and / or at least one inductor; a charging and discharging unit, the receiving end of which is connected with the power supply, used for charging when the device circuit is in a power supply state; the output end of the charging and discharging unit is connected with the power-consuming device in the device circuit; a power-off detection unit, which comprises a voltage comparison circuit and a voltage dividing resistor; the voltage comparison circuit has two receiving ends, one of which is connected with the conversion unit in series, and the other of which is connected with the voltage dividing resistor in series; the voltage dividing resistor is also connected with the power supply in series; the voltage comparison circuit is used for comparing the voltage of the conversion unit with the voltage of the voltage dividing resistor, and judging whether the device circuit is in a power-off state according to the comparison result; the charging and discharging unit is also used for discharging when the voltage comparison circuit judges that the device circuit is in a power-off state.

2. The power disconnect protection system of claim 1, wherein, a signal processing unit is further comprised; the signal processing unit is connected with the output end of the voltage comparison circuit and the charging and discharging unit respectively; the voltage comparison circuit is also used for sending a first signal to the signal processing unit when judging that the device circuit is in a power-off state; the signal processing unit is used for sending a second signal to the charging and discharging unit to control the charging and discharging unit to discharge when receiving the first signal.

3. The power disconnect protection system of claim 1, wherein, the power-consuming device in the device circuit comprises a valve device; the power-off protection system further comprises an interlocking unit; the interlocking unit is connected with the output end of the charging and discharging unit and the control end of the valve device respectively; the interlocking unit is used for sending a third signal to the valve device to control the valve device to switch to a preset safe state under the power supply of the charging and discharging unit.

4. The power disconnect protection system of claim 3, wherein, the interlocking unit is connected with the conversion unit to connect the output end of the charging and discharging unit through the conversion unit.

5. The power disconnect protection system of claim 2, wherein, the charging and discharging unit comprises an energy storage device, a charging circuit and a discharging control circuit; the energy storage device is used for storing electric energy; the charging circuit is connected with the energy storage device and the power supply respectively, and is used for transmitting the electric energy output by the power supply to the energy storage device; the discharging control circuit is connected with the energy storage device and the signal processing unit respectively; the discharging control circuit is used for controlling the energy storage device to discharge when receiving the second signal.

6. The power disconnect protection system of claim 5, wherein, the energy storage device comprises a battery or a super capacitor.

7. The power disconnect protection system of claim 2, wherein, the voltage comparison circuit comprises a first voltage dividing circuit, a second voltage dividing circuit, a voltage comparator and a signal output circuit; the voltage comparator has two signal input ends and one signal output end; the first voltage dividing circuit is connected with the voltage dividing resistor and one signal input end of the voltage comparator respectively; the second voltage dividing circuit is connected with the conversion unit and the other signal input end of the voltage comparator respectively; the signal output circuit is connected with the signal output end of the voltage comparator and the signal processing unit respectively. The first voltage dividing circuit and the second voltage dividing circuit are both used to reduce the received voltage in a specified ratio; the voltage comparator is used to compare the voltage received by two signal inputs and output the corresponding comparison result through a signal output.

8. The power disconnect protection system of claim 7, wherein, The first voltage dividing circuit comprises a first diode, a first resistor and a first voltage stabilizing unit; one end of the first diode and the first resistor are connected in series between the voltage dividing resistor and one signal input of the voltage comparator; one end of the first voltage stabilizing unit is connected in series in the first voltage dividing circuit and the other end is grounded. The second voltage dividing circuit comprises a second resistor and a second voltage stabilizing unit; the second resistor is connected in series between the conversion unit and the other signal input of the voltage comparator; one end of the second voltage stabilizing unit is connected in series in the second voltage dividing circuit and the other end is grounded.

9. A semiconductor process apparatus, characterized by, The power-off protection system comprises a plurality of electrical devices, a device circuit and the power-off protection system according to any one of claims 1-8; wherein, The device circuit is connected with the plurality of electrical devices and is used to send control signals to the corresponding electrical devices and provide power supply; The power-off protection system is connected with the device circuit and is used to send control signals or power supply to the electrical devices when the device circuit is powered off.

10. The semiconductor process apparatus according to claim 9, wherein The semiconductor process equipment comprises a process chamber; the plurality of electrical devices comprises an electrically controlled valve and a mass flow meter; The electrically controlled valve and the mass flow meter are connected with the gas inlet and / or gas outlet of the process chamber and are used to control the gas inlet and outlet amount of the process chamber; The power-off protection system is used to send a closing signal to the electrically controlled valve and the mass flow meter to stop the gas inlet and outlet of the process chamber when the device circuit is powered off.

Images