Fault Detection Method for Inverse Parallel Thyristor and Power Control Device

Abstract

To provide a failure detection method for antiparallel thyristors for detecting failures in the thyristors and a power supply device.SOLUTION: The present invention relates to a failure detection method for antiparallel thyristors including a first thyristor and a second thyristor which are connected in parallel and in inverse directions, and being configured to control power to be supplied from an AC power source to a load. The failure detection method for the antiparallel thyristors includes the steps of: stopping an output command of the second thyristor, performing an output command to the first thyristor and detecting a voltage or a current supplied to the load as a first detection value; stopping the output command of the first thyristor, performing the output command to the second thyristor and detecting the voltage or the current supplied to the load as a second detection value; and determining failures in the antiparallel thyristors based on a differential between the first detection value and the second detection value.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for detecting a failure of an antiparallel thyristor and a power control device.

Background Art

[0002] A substrate processing apparatus is provided with a heater for heating a substrate. An antiparallel thyristor is provided as a component for controlling the output of the heater.

[0003] Patent Document 1 discloses a failure detector for an antiparallel thyristor that detects failures of a first thyristor and a second thyristor connected in antiparallel.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In an antiparallel thyristor, when any one of the thyristors fails, it is required to detect the failure.

[0006] In one aspect, the present disclosure provides a method for detecting a failure of an antiparallel thyristor and a power supply device that detects a failure of a thyristor.

Means for Solving the Problems

[0007] According to one aspect, there is provided a method for detecting a failure of an antiparallel thyristor having a first thyristor and a second thyristor connected in parallel and in reverse, and controlling power supplied from an AC power source to a load, the method comprising: stopping an output command of the second thyristor and outputting an output command to the first thyristor to detect a voltage or current supplied to the load as a first detected value; stopping an output command of the first thyristor and outputting an output command to the second thyristor to detect a voltage or current supplied to the load as a second detected value; and determining a failure of the antiparallel thyristor based on a difference between the first detected value and the second detected value.

Effect of the Invention

[0008] According to one aspect, it is possible to provide a method for detecting a failure of an antiparallel thyristor and a power supply device for detecting a failure of a thyristor.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are assigned to the same components, and redundant descriptions may be omitted.

[0011] <Substrate Processing Apparatus> The substrate processing apparatus 100 of the present embodiment will be described with reference to FIG. 1. FIG. 1 is an example of a cross-sectional view of the substrate processing apparatus 100.

[0012] The substrate processing apparatus 100 has a processing container 101 formed of a cylindrical body made of, for example, aluminum or the like. Inside the processing container 101, a mounting table 102 for mounting the substrate W is disposed. The mounting table 102 has, for example, a base made of aluminum, nickel, or the like, and a member made of an electrically insulating material (dielectric material) disposed on the base. The member made of an electrically insulating material is formed of, for example, ceramics of aluminum nitride (AlN). Inside the member made of an electrically insulating material, a heater 103 is provided. The heater 103 generates heat when supplied with power from a power supply device (see FIG. 2 described later), and adjusts the temperature of the mounting table 102 and the substrate W mounted on the mounting table 102. Further, a plurality of compartments may be formed in the member made of an electrically insulating material, and the heaters 103 capable of being independently supplied with power may be provided in each compartment. In this case, power supply devices are provided corresponding to the heaters 103 in each compartment. On the mounting table 102, three substrate support pins (not shown) for substrate transfer are provided so as to be able to project and retract with respect to the surface of the mounting table 102.

[0013] At the bottom of the processing container 101, an exhaust port 111 is provided. An exhaust pipe 112 is connected to the exhaust port 111. A throttle valve 113 for pressure adjustment and a vacuum pump 114 are connected to the exhaust pipe 112, and the inside of the processing container 101 can be evacuated. On the other hand, a substrate transfer inlet / outlet 121 is formed in the side wall of the processing container 101, and the substrate transfer inlet / outlet 121 can be opened and closed by a gate valve G. Then, the substrate W is carried in and out with the gate valve G open.

[0014] In the center of the top wall of the processing container 101, a gas inlet 131 is provided. A gas supply pipe 132 is connected to the gas inlet 131. A gas supply source 133 for supplying a processing gas used for processing is connected to the gas supply pipe 132. Further, a gas control unit 134 including a gas flow controller, a valve, and the like is interposed in the gas supply pipe 132.

[0015] In the substrate processing apparatus 100 configured as described above, after opening the gate valve G and placing the substrate W on the mounting table 102, the gate valve G is closed, the inside of the processing chamber 101 is evacuated by the vacuum pump 114, and the pressure inside the processing chamber 101 is adjusted to a predetermined pressure by the throttle valve 113. At the same time, the temperature of the substrate W on the mounting table 102 is adjusted to a predetermined temperature by the heater 103. Then, a processing gas is supplied into the processing chamber 101 from the gas supply source 133 through the gas supply pipe 132 and the gas inlet 131, and a desired process is performed on the substrate W.

[0016] Note that the configuration of the substrate processing apparatus 100 is not limited to the configuration shown in FIG. 1. The substrate processing apparatus 100 may be a plasma processing apparatus that generates plasma in the processing chamber 101 and performs processing on the substrate W.

[0017] Next, a power supply device that supplies power to the heater 103 will be described with reference to FIG. 2. FIG. 2 is an example of a diagram showing the configuration of a power supply device that supplies power to the heater 103.

[0018] The power supply device includes an AC power supply 10, an antiparallel thyristor 20, and a control unit 30. The antiparallel thyristor 20 and the control unit 30 constitute a power control device that controls the power supplied from the AC power supply 10 to the heater (load) 103.

[0019] The AC power supply 10 supplies AC power to the heater 103 via the antiparallel thyristor 20.

[0020] The antiparallel thyristor 20 has a first thyristor 21 and a second thyristor 22 connected in parallel and in opposite directions. The first thyristor 21 is turned on (conducted) by an output command from the temperature control unit 31 of the control unit 30 and outputs a positive voltage from the AC power supply 10 to the heater 103, and is turned off (blocked) when the AC voltage from the AC power supply 10 becomes a negative voltage. The second thyristor 22 is turned on (conducted) by an output command from the temperature control unit 31 of the control unit 30 and outputs a negative voltage from the AC power supply 10 to the heater 103, and is turned off (blocked) when the AC voltage from the AC power supply 10 becomes a positive voltage.

[0021] The mounting table 102 is provided with a temperature detection unit 41 that detects the temperature of the mounting table 102. Further, the power supply device is provided with a voltage detection unit 42 that detects the AC voltage supplied to the heater 103. Further, the power supply device is provided with a current detection unit 43 that detects the AC current supplied to the heater 103.

[0022] The control unit 30 includes a temperature control unit 31 and a failure determination unit 32.

[0023] The temperature control unit 31 controls the first thyristor 21 and the second thyristor 22 by controlling the timing of the output command. Thereby, the temperature control unit 31 controls the power supplied to the heater 103 and controls the temperature of the heater 103. The temperature control unit 31 receives the target temperature of the mounting table 102. Further, the temperature control unit 31 receives the detected temperature of the mounting table 102 detected by the temperature detection unit 41. The temperature control unit 31 controls the first thyristor 21 and the second thyristor 22 based on the target temperature and the detected temperature of the temperature detection unit 41 so that the detected temperature approaches the target temperature.

[0024] The failure determination unit 32 determines the failure of the antiparallel thyristor 20 (the first thyristor 21, the second thyristor 22). The failure determination unit 32 receives the supply voltage of the heater 103 detected by the voltage detection unit 42. Further, the failure determination unit 32 receives the supply current of the heater 103 detected by the current detection unit 43.

[0025] Here, the failure modes of the antiparallel thyristor 20 are classified into the following three types.

[0026] The first failure mode is the case where one of the first thyristor 21 and the second thyristor 22 has a short (ON) failure.

[0027] The second failure mode is the case where one of the first thyristor 21 and the second thyristor 22 has an open (OFF) failure.

[0028] The third failure mode is a state where both the first thyristor 21 and the second thyristor 22 have failed. That is, when both the first thyristor 21 and the second thyristor 22 have an open (OFF) failure, when both the first thyristor 21 and the second thyristor 22 have a short (ON) failure, or when one of the first thyristor 21 and the second thyristor 22 has an open (OFF) failure and the other has a short (ON) failure.

[0029] Figure 3 shows an example of the power supplied to the heater 103 due to the failure state of the antiparallel thyristor 20. In each graph, the horizontal axis represents time and the vertical axis represents voltage. Also, the AC waveform of the AC power supply 10 is shown by a solid line. Further, the voltage supplied to the heater 103 when the first thyristor 21 and the second thyristor 22 are ON is shown with cross-hatching (dot hatching). Note that the voltage detected by the voltage detection unit 42 corresponds to the area of the cross-hatching (dot hatching).

[0030] Also, the upper row shows the state where the antiparallel thyristor 20 is normal (without failure). The middle row shows the case where the positive-side first thyristor 21 has a short (ON) failure. The lower row shows the case where the positive-side first thyristor 21 has an open (OFF) failure.

[0031] Also, "During control" in the left column shows the case where the first thyristor 21 and the second thyristor 22 are controlled. "+ side output" in the middle column shows the case where the positive-side first thyristor 21 is controlled and the negative-side second thyristor 22 is controlled while remaining OFF. "- side output" in the right column shows the case where the negative-side second thyristor 22 is controlled and the positive-side first thyristor 21 is controlled while remaining OFF.

[0032] Here, during normal operation, as shown in the upper left graph, the temperature control unit 31 can control the power supplied to the heater 103 and the temperature of the heater 103 by controlling the timing of the output commands of the first thyristor 21 and the second thyristor 22.

[0033] When one of the thyristors (the first thyristor 21) has a short - circuit failure, as shown in the graph on the upper - middle left side, the temperature control unit 31 can increase or decrease the power supplied to the heater 103 by controlling the timing of the output command of the second thyristor 22, and can control the temperature of the heater 103.

[0034] Also, when one of the thyristors (the first thyristor 21) has an open - circuit failure, as shown in the graph on the lower - left side, the temperature control unit 31 can increase or decrease the power supplied to the heater 103 by controlling the timing of the output command of the second thyristor 22, and can control the temperature of the heater 103.

[0035] In this way, even when one of the first thyristor 21 and the second thyristor 22 fails, apparently, the temperature of the heater 103 can be controlled. If the use of the heater 103 is continued in a state where one of the first thyristor 21 and the second thyristor 22 has failed, the heater 103 may be damaged. Therefore, even when one of the first thyristor 21 and the second thyristor 22 fails, a fault - detection method for detecting the failure of the antiparallel thyristor 20 is required.

[0036] <Fault - detection method> The fault - detection method of the antiparallel thyristor 20 will be described with reference to FIG. 4. FIG. 4 is an example of a flowchart for explaining the fault - detection method of the antiparallel thyristor 20. The following processing is executed at a timing different from the timing when the substrate processing apparatus 100 processes the substrate W (for example, during the idle time of the substrate processing apparatus 100, during the temperature - rising process of the mounting table 102, etc.).

[0037] In step S101, the temperature control unit 31 of the control unit 30 controls the temperature of the heater 103. The temperature control unit 31 controls the power supplied to the heater 103 by controlling the timing of the output commands of the first thyristor 21 and the second thyristor 22, and controls the temperature of the heater 103.

[0038] In step S102, the failure determination unit 32 of the control unit 30 determines whether the temperature of the heater 103 can be controlled. If the temperature of the heater 103 cannot be controlled (S102·NO), the process of the control unit 30 proceeds to step S103. On the other hand, if the temperature of the heater 103 can be controlled (S102·YES), the process of the control unit 30 proceeds to step S104.

[0039] In step S103, the failure determination unit 32 of the control unit 30 determines that both the first thyristor 21 and the second thyristor 22 have failed (third failure mode). Then, the failure detection process of the control unit 30 ends.

[0040] In step S104, the temperature control unit 31 of the control unit 30 stops the output of the heater 103. That is, the temperature control unit 31 stops the output command to the first thyristor 21 and the second thyristor 22 for a predetermined time. The failure determination unit 32 of the control unit 30 stores the voltage (third detection value) detected by the voltage detection unit 42 and the current (third detection value) detected by the current detection unit 43 in this state.

[0041] Note that in a configuration where the voltage detection unit 42 and the current detection unit 43 have capacitors, the stop time is determined in consideration of the discharge time of the capacitors.

[0042] In step S105, the failure determination unit 32 of the control unit 30 determines whether the first thyristor 21 and the second thyristor 22 are operating normally. Here, when one of the first thyristor 21 and the second thyristor 22 has a short (ON) failure, the voltage detected by the voltage detection unit 42 (the third detection value) and the current detected by the current detection unit 43 (the third detection value) will not be near zero. Therefore, when the voltage (the third detection value) detected by the voltage detection unit 42 is less than a predetermined threshold value (the second threshold value), the failure determination unit 32 determines that the first thyristor 21 and the second thyristor 22 are operating normally. On the other hand, when the voltage (the third detection value) detected by the voltage detection unit 42 is greater than or equal to the predetermined threshold value (the second threshold value), the failure determination unit 32 determines that the first thyristor 21 and the second thyristor 22 are not operating normally. Note that instead of the voltage detected by the voltage detection unit 42, the determination may be made based on the current detected by the current detection unit 43. If the first thyristor 21 and the second thyristor 22 are not operating normally (S105·NO), the process of the control unit 30 proceeds to step S106. On the other hand, if the first thyristor 21 and the second thyristor 22 are operating normally (S105·YES), the process of the control unit 30 proceeds to step S107.

[0043] In step S106, the failure determination unit 32 of the control unit 30 determines that one of the first thyristor 21 and the second thyristor 22 has a short failure (the first failure mode). Then, the failure detection process of the control unit 30 ends.

[0044] In step S107, the temperature control unit 31 of the control unit 30 issues an output command to turn on only one of the first thyristors 21 and stops the output command to turn off the other second thyristor 22. The failure determination unit 32 of the control unit 30 stores the voltage (the first detection value) detected by the voltage detection unit 42 and the current (the first detection value) detected by the current detection unit 43 in this state.

[0045] In step S108, the temperature control unit 31 of the control unit 30 outputs a command to turn on only the other second thyristor 22, and stops outputting a command to turn off one first thyristor 21. The failure determination unit 32 of the control unit 30 stores the voltage (first detection value) detected by the voltage detection unit 42 and the current (first detection value) detected by the current detection unit 43 in this state.

[0046] In step S109, the failure determination unit 32 of the control unit 30 determines whether the difference between the voltage (first detection value) detected in step S106 and the voltage (first detection value) detected in step S107 is within a threshold value. Alternatively, the failure determination unit 32 of the control unit 30 determines whether the difference between the current (first detection value) detected in step S106 and the current (first detection value) detected in step S107 is within a threshold value. If the difference is not within the threshold value (first threshold value) (S109·NO), the process of the control unit 30 proceeds to step S110. On the other hand, if the difference is within the threshold value (first threshold value) (S109·YES), the process of the control unit 30 proceeds to step S111.

[0047] In step S110, the failure determination unit 32 of the control unit 30 determines that one of the first thyristor 21 and the second thyristor 22 has an open failure (second failure mode). Then, the failure detection process of the control unit 30 ends.

[0048] In step S111, the failure determination unit 32 of the control unit 30 determines that there is no abnormality (no failure) in the first thyristor 21 and the second thyristor 22. Then, the failure detection process of the control unit 30 ends.

[0049] Thus, according to the failure detection method of the antiparallel thyristor 20 according to this embodiment, even if either one of the first thyristor 21 and the second thyristor 22 fails, the failure of the thyristor can be detected. Thereby, it is possible to prevent the heater 103 from being damaged.

[0050] For example, when there is no fault in the first thyristor 21 and the second thyristor 22, the voltage detected in step S107 corresponds to the area of the shaded portion of the graph in the central column of the upper row in FIG. 3. Also, the voltage detected in step S108 corresponds to the area of the shaded portion of the graph in the right column of the upper row in FIG. 3. Therefore, the difference between the first detection value in step S107 and the second detection value in step S108 approaches zero.

[0051] On the other hand, in the case of an open fault in the first thyristor 21, the voltage detected in step S107 becomes zero as shown in the graph in the central column of the lower row in FIG. 3. On the other hand, the voltage detected in step S108 corresponds to the area of the shaded portion of the graph in the right column of the lower row in FIG. 3. Therefore, the difference between the first detection value in step S107 and the second detection value in step S108 increases. Therefore, the fault determination unit 32 of the control unit 30 can determine the fault of the inverse parallel thyristor 20 based on these differences.

[0052] Note that in the case of a short circuit fault in the first thyristor 21, the voltage detected in the process of step S107 corresponds to the area of the shaded portion of the graph in the central column of the middle row in FIG. 3. Also, the voltage detected in step S108 corresponds to the area of the shaded portion of the graph in the right column of the middle row in FIG. 3. Therefore, the difference between the first detection value in step S107 and the second detection value in step S108 increases. Therefore, the short circuit fault of the first thyristor 21 can also be determined by the processes shown from step S107 to step S109.

[0053] Further, in a multi-heater in which a plurality of compartments are formed in a member made of an electrically insulating material, and heaters 103 capable of being powered independently are provided in each compartment, when a failure occurs in the antiparallel thyristor 20 corresponding to any one of the heaters, a temperature difference may occur in the member made of the electrically insulating material, and the member made of the electrically insulating material or the heater 103 may be damaged. According to the method for detecting a failure of the antiparallel thyristor 20 according to the present embodiment, since a failure of either one of the first thyristor 21 and the second thyristor 22 can also be detected, it is possible to prevent the member made of the electrically insulating material and the heater 103 from being damaged.

[0054] In step S104, when one of the voltage (third detection value) detected by the voltage detection unit 42 and the current (third detection value) detected by the current detection unit 43 is less than the threshold value (second threshold value) and the other is equal to or greater than the threshold value (second threshold value), it can be detected that an offset has occurred in the detection value of the voltage detection unit 42 or the current detection unit 43.

Explanation of Reference Numerals

[0055] 100 Substrate processing apparatus 102 Mounting table 103 Heater 10 AC power supply 20 Antiparallel thyristor 21 First thyristor 22 Second thyristor 30 Control unit 31 Temperature control unit 32 Failure determination unit 41 Temperature detection unit 42 Voltage detection unit 43 Current detection unit

Claims

1. A method for detecting a fault in an antiparallel thyristor having a first thyristor and a second thyristor connected in parallel and in reverse, and controlling power supplied from an AC power source to a load, comprising: stopping the output command of the second thyristor, and outputting a command to the first thyristor to detect the voltage or current supplied to the load as a first detected value; stopping the output command of the first thyristor, and outputting a command to the second thyristor to detect the voltage or current supplied to the load as a second detected value; determining a fault in the antiparallel thyristor based on a difference between the first detected value and the second detected value. A method for detecting a fault in an antiparallel thyristor.

2. The step of determining a fault in the antiparallel thyristor based on a difference between the first detected value and the second detected value is: when the difference between the first detected value and the second detected value is equal to or greater than a predetermined first threshold value, determining that the antiparallel thyristor is faulty. The method for detecting a fault in an antiparallel thyristor according to Claim 1.

3. stopping the output commands of the first thyristor and the second thyristor, and detecting the voltage or current supplied to the load as a third detected value; determining a fault in the antiparallel thyristor based on the third detected value. The method for detecting a fault in an antiparallel thyristor according to Claim 1 or Claim 2.

4. The step of determining a fault in the antiparallel thyristor based on the third detected value is: when the third detected value is equal to or greater than a predetermined second threshold value, determining that the antiparallel thyristor is faulty. The method for detecting a fault in an antiparallel thyristor according to Claim 3.

5. The load is a heater provided in a member made of an electrically insulating material. The fault detection method according to any one of Claims 1 to 4.

6. An antiparallel thyristor having a first thyristor and a second thyristor connected in parallel and in reverse, and controlling power supplied from an AC power source to a load, a power control device comprising a control unit for controlling the antiparallel thyristor, wherein the control unit stops the output command of the second thyristor, and outputs a command to the first thyristor to detect the voltage or current supplied to the load as a first detected value. A step of stopping the output command of the first thyristor and outputting a command to the second thyristor to detect the voltage or current supplied to the load as a second detection value; A step of determining a failure of the antiparallel thyristor based on a difference between the first detection value and the second detection value, and is configured to be executable; A power control device.

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