JP6976416B2 - Plasma device - Google Patents

Description

The present disclosure relates to a plasma apparatus that irradiates an object to be processed with plasma.

Patent Document 1 describes a plasma device that irradiates plasma in a vacuum. In this plasma device, warm-up operation is performed when the temperature of the discharge tube at the start of driving is lower than a predetermined set temperature, but in warm-up operation, when the temperature of the discharge tube falls within an appropriate range. Is stopped by.

JP 2011-29475

Overview

The problem to be solved

An object of the present disclosure is to allow warm-up operation to be performed in a mode different from that of the plasma apparatus described in Patent Document 1.

Means, actions and effects to solve problems

In the plasma apparatus according to the present disclosure, the warm-up operation is performed based on the stop time, which is the time during which the plasma apparatus has been continuously stopped immediately before the drive of the plasma apparatus is started. Will be. For example, when the stop time is long, the warm-up operation can be performed for a longer time than when the stop time is short.

As described above, the warm-up operation is performed based on the stop time of the plasma device, which is different from the mode of the warm-up operation performed in the plasma device described in Patent Document 1. Further, Patent Document 1 does not describe that the warm-up operation is performed based on the stop time of the plasma apparatus.

It is a perspective view of the plasma apparatus which is one Embodiment of this disclosure. It is sectional drawing of a part of the said plasma apparatus. It is sectional drawing of the part including a part of FIG. 2 of the said plasma apparatus. It is a perspective view of the dielectric surrounding member which is a constituent member of the plasma apparatus, and FIGS. 4A, 4B, and 4C are perspective views when the dielectric surrounding member is viewed from different angles, respectively. It is sectional drawing of the nozzle attached to and detached from the said plasma apparatus. It is a figure which conceptually shows the periphery of the control device of the said plasma device. It is a figure which shows the switching circuit of the said power supply device. It is a figure which shows the operating state of the said plasma apparatus. It is a figure which shows another operating state of the said plasma apparatus. It is a flowchart which shows the warm-up operation control program stored in the storage part of the said control device.

Embodiment

Hereinafter, the plasma apparatus according to the present disclosure will be described with reference to the drawings. This plasma device generates plasma at atmospheric pressure.

The plasma device shown in FIG. 1 includes a plasma generation unit 12, a heating gas supply unit 14, a power supply device 16 shown in FIG. 6, and the like. The plasma generation unit 12 and the heating gas supply unit 14 are provided side by side. The plasma generation unit 12 converts the supplied processing gas into plasma to generate plasma. The heating gas supply unit 14 supplies the heating gas obtained by heating the heating gas to the plasma generation unit 12. In this plasma apparatus, the plasma generated by the plasma generation unit 12 is output together with the heating gas supplied by the heating gas supply unit 14, and is irradiated to the object W to be processed. In FIG. 1, the processing gas is supplied and plasma is output in the direction of the arrow P.

As shown in FIGS. 2 to 4, the plasma generation unit 12 includes a generation unit main body 18 formed of an insulator such as ceramics, a pair of electrode portions 24, 26, a dielectric surrounding member 22, and the like. The generator body 18 generally has a shape extending in the longitudinal direction, and the pair of electrode portions 24, 26 are held apart from each other in the width direction. Further, a discharge space 21 is provided between the pair of electrode portions 24, 26 of the generation portion main body 18, and the processing gas is supplied in the P direction. Hereinafter, in the present plasma apparatus, the width direction of the generation unit main body 18, that is, the pair of electrode portions 24, 26 (hereinafter, “pair” is omitted, and the electrode portions 24, 26 or a plurality of electrode portions 24, 26 are simply omitted. The same applies to other terms.) The direction in which the plasma generation unit 12 and the heating gas supply unit 14 are lined up is the y direction, and the longitudinal direction of the generation unit main body 18 is the longitudinal direction. The z direction. The z direction is the same as the P direction, and the side where the processing gas is supplied is the upstream side, and the side where the plasma is output is the downstream side. The x-direction, y-direction, and z-direction are orthogonal to each other.

Each of the plurality of electrode portions 24, 26 has a shape extending in the longitudinal direction, and includes a pair of electrode rods 27, 28 and a pair of electrode holders 29, 30, respectively. Each of the plurality of electrode holders 29 and 30 has a larger diameter than the plurality of electrode rods 27 and 28, respectively, and the electrode rods 27 and 28 are held and fixed to each of the electrode holders 29 and 30 at eccentric positions. To. Further, each of the electrode rods 27 and 28 is held by the electrode holders 29 and 30, respectively, and a part of the electrode rods 27 and 28 is in a state of protruding from the electrode holders 29 and 30. The electrode portions 24, 26 (electrode holders 29, 30 and electrode rods 27, 28) extend in the z direction, that is, in the same direction as the processing gas supply direction P, and the electrode holders 29, 30 are on the upstream side, and the electrode rods 27, 28 is held by the generator main body 18 in a posture located on the downstream side. Further, the direction x in which the electrode portions 24 and 26 are separated from each other and the direction z (P) in which the processing gas is supplied intersect. The distance D1 between the electrode holders 29 and 30 is smaller than the distance D2 between the electrode rods 26 and 27 (D1 <D2).

The electrode holders 29 and 30 are made of a conductive material, respectively, and have a function as an electrode. The electrode rods 27 and 28 are fixed to the electrode holders 29 and 30, respectively, in a state where they can be energized with each other. In other words, the electrode holders 29 and 30 and the electrode rods 27 and 28 are electrically integrally provided. Further, in a state where the electrode portions 24 and 26 are held by the generator main body 18 and connected to the power supply device 16, voltage is applied to both the electrode rods 27 and 28 and the electrode holders 29 and 30, and these electrode rods 27 are applied. , 28 and the electrode holders 29 and 30 all act as electrodes.

In this way, since each of the electrode rods 27 and 28 and each of the electrode holders 29 and 30 are electrically integrally provided, the power supply device 16 can be either the electrode holders 29 or 30 or the electrode rods 27 or 28. You only have to connect to one of them, and the wiring can be simplified accordingly.
An AC voltage of an arbitrary size and frequency is applied to the electrode rods 27 and 28 and the electrode holders 29 and 30.

The dielectric enclosing member 22 covers the outer periphery of the electrode holders 29 and 30, and is manufactured of a dielectric (also referred to as an insulator) such as ceramics. As shown in FIGS. 4A to 4C, the dielectric surrounding member 22 includes a pair of electrode covers 34, 36 provided apart from each other and a connecting portion 38 connecting the pair of electrode covers 34, 36.

Each of the plurality of electrode covers 34 and 36 has a hollow tubular shape, and both ends in the longitudinal direction are openings. The electrode covers 34, 36 are arranged in a posture in which the longitudinal direction extends in the z direction, and the electrode holders 29, 30 are mainly located on the inner peripheral side of the electrode covers 34, 36. A gap is provided between the inner peripheral surfaces of the electrode covers 34 and 36 and the outer peripheral surfaces of the electrode holders 29 and 30, respectively, and these gaps are referred to as gas passages 34c and 36c, which will be described later. Further, the downstream end portions 27s and 28s, which are the downstream end portions of the electrode rods 27 and 28 that protrude from the above-mentioned electrode holders 29 and 30, are from the downstream opening of the electrode covers 34 and 36. It is protruding.

A gas passage 40 penetrating in the z direction is formed in the connecting portion 38. In this embodiment, as shown in FIG. 3, the peripheral wall forming the gas passage 40 of the connecting portion 38 is integrally formed with the electrode covers 34 and 36. Inside the gas passage 40, there is no member (which can be referred to as a dielectric) made of a dielectric (which does not contain gas; the same applies hereinafter). In other words, there is no member manufactured of a dielectric different from the dielectric surrounding member 22 between the portions of the electrode covers 34 and 36 facing each other.

A plurality of gas passages 42, 44, 46 and the like are formed on the upstream side of the portion where the electrode portions 24 and 26 of the generation portion main body 18 are held. The nitrogen gas supply device 50 shown in FIG. 6 is connected to the gas passages 42 and 44, and the nitrogen gas supply device 50 and the active gas for supplying the active gas dry air (including active oxygen) are connected to the gas passage 46. The supply device 52 is connected. The nitrogen gas supply device 50 includes a nitrogen gas source and a flow rate adjusting mechanism, and can supply nitrogen gas at a desired flow rate. The active gas supply device 52 includes an active gas source and a flow rate adjusting mechanism, and can supply the active gas at a desired flow rate. In this embodiment, the processing gas is assumed to include an active gas supplied from the active gas supply device 52 and a nitrogen gas (one aspect of the inert gas) supplied from the nitrogen gas supply device 50. ..

The gas passages 34c and 36c inside the electrode covers 34 and 36 are communicated with the gas passages 42 and 44 at the openings on the upstream side of the electrode covers 34 and 36, respectively. Nitrogen gas is supplied to the gas passages 34c and 36c in the P direction, respectively.

A gas passage 40 formed in the dielectric surrounding member 22 communicates with the gas passage 46. A processing gas containing a nitrogen gas and an active gas is supplied to the gas passage 40 in the P direction.

A discharge chamber 56 is formed between the downstream end portions 27s and 28s of the pair of electrode rods 27 and 28 protruding from the electrode covers 34 and 36 of the generation unit main body 18, and the discharge chamber 56 is formed on the downstream side in the x direction. A plurality of plasma passages 60a, 60b ... Extending in the z direction (six in this embodiment) are formed by arranging them at intervals. The upstream ends of the plurality of plasma passages 60a, 60b ... Each open into the discharge chamber 56. Further, a plurality of nozzles 80, 83, etc. of different types are detachably attached to the downstream end portion of the generation unit main body 18. The nozzles 80, 83 and the like are manufactured of an insulator such as ceramics. In this embodiment, the discharge space 21 is configured by the discharge chamber 56, the gas passage 40, and the like.

As shown in FIGS. 1 and 2, the heating gas supply unit 14 includes a protective cover 70, a gas pipe 72, a heater 73, a connecting unit 74, and the like. The protective cover 70 is attached to the generation unit main body 18 of the plasma generation unit 12. The gas pipe 72 is arranged so as to extend in the z direction inside the protective cover 70, and a heating gas supply device (see FIG. 5) 76 is connected to the gas pipe 72. The heating gas supply device 76 includes a heating gas source and a flow rate adjusting unit, and can supply the heating gas at a desired flow rate. The heating gas may be an active gas such as dry air or an inert gas such as nitrogen. Further, a heater 73 is arranged on the outer peripheral side of the gas pipe 72, the gas pipe 72 is heated by the heater 73, and the heating gas flowing through the gas pipe 72 is heated.

The connecting portion 74 connects the gas pipe 72 to the nozzle 80, and includes a heated gas supply passage 78 that is generally L-shaped in side view. With the nozzle 80 attached to the generation unit main body 18, the heating gas supply passage 78 has one end communicating with the gas pipe 72 and the other end communicating with the heating gas passage 62 formed in the nozzle 80. ..

As shown in FIGS. 2 and 3, the nozzle 80 includes a passage structure 81 in which a plurality of (six in this embodiment) plasma output passages 80a, 80b, ... Including the main body 82. The passage structure 81 and the nozzle body 82 are attached to the generator body 18 with the passage structure 81 located inside the storage chamber 82a formed in the nozzle body 82, respectively, whereby the nozzle is attached. 80 is attached to the generator main body 18. In this way, the plasma passages 60a, 60b ... And the plasma output passages 80a, 80b ... Are communicated with each other in a state where the nozzle 80 is attached to the generation unit main body 18. Further, heating gas is supplied to the gap between the accommodation chamber 82a of the nozzle body 82 and the passage structure 81 via the heating gas passage 62. In the nozzle 80, plasma and the like and heating gas are output from the opening 82b at the tip of the accommodation chamber 82a of the nozzle body 82.

A nozzle 83 shown in FIG. 5, which is different from the nozzle 80, can also be attached to the generator main body 18. One plasma output passage 83a is formed in the passage structure 84 of the nozzle 83. Further, the passage structure 84 and the nozzle main body 85 are attached to the generation unit main body 18 in a state where the passage structure 84 is located in the accommodation chamber 85a formed inside the nozzle main body 85, respectively. With the nozzle 83 attached to the generation unit main body 18 in this way, the plurality of plasma passages 60a, 60b ... And the plasma output passage 83a are communicated with each other. Further, heating gas is supplied to the gap between the accommodation chamber 85a of the nozzle body 85 and the passage structure 84, and plasma and the like and the heating gas are output from the opening 85b at the tip of the accommodation chamber 85a.

As shown in FIG. 6, this plasma device includes a computer-based control device 86. The control device 86 includes an execution unit 86c, a storage unit 86m, an input / output unit 86i, a timer 86t, and the like, and the input / output unit 86i includes a nitrogen gas supply device 50, an active gas supply device 52, a heating gas supply device 76, and a heater. 73, a power supply device 16, a display 87, etc. are connected, and a start switch 88, a stop switch 89, etc. are connected. The display 87 shows the state of the plasma apparatus and the like.

The start switch 88 is a switch operated when instructing the drive of the plasma device, and the stop switch 89 is a switch operated when instructing the stop of the plasma device. For example, by connecting the power cable 90 of the plasma device to an outlet and inserting a breaker (not shown), the AC voltage can be supplied to the plasma device from the commercial AC power supply 93, and the operation of the control device 86 starts. Will be done. As a result, the plasma device switches from the undriveable state, which is the undriveable state, to the driveable state, which enables the drive. Then, in the driveable state, the plasma device is started to be driven by the ON operation of the start switch 88, and the plasma device is generated by the ON operation of the stop switch 89 while the plasma device is being driven. The drive for is stopped. That is, when the stop switch 89 is turned on, the voltage is not applied to the electrodes 24 and 26, and the heating gas is not heated, but the cooling device (not shown) is operated. May be started.

The power supply device 16 includes a power cable 90, a current sensor 94, an A / D (alternating current / direct current) converter 95, a switching circuit 96, a booster 98, and the like. With the power cable 90 connected to an outlet, the AC voltage supplied from the commercial AC power supply 93 is converted to a DC voltage by the A / D converter 95, and PWM (Plus Width Modulation) control is performed by the switching circuit 96. Is done. Further, the pulse signal of the voltage of the desired frequency obtained by performing the PWM control is boosted by the booster 98 and applied to the electrode portions 24 and 26. Further, the alternating current flowing through the power supply device 16 is detected by the current sensor 94.

As shown in FIG. 7, the switching circuit 96 is composed of bridge connections of four first to fourth switching elements 101 to 104. In this embodiment, a MOSFET element is used as the switching element. For the first switching element 101, the drain D is connected to the high voltage terminal 105 of the output unit of the A / D converter 95, and the source S is connected to the first output terminal 106. For the second switching element 102, the drain D is connected to the first output terminal 106, and the source S is connected to the low voltage terminal 107 of the A / D converter 95. For the third switching element 103, the drain D is connected to the high voltage terminal 105 of the A / D converter 95, and the source S is connected to the second output terminal 108. For the fourth switching element 104, the drain D is connected to the second output terminal 108, and the source S is connected to the low voltage terminal 107 of the A / D converter 94.

The first output terminal 106 and the second output terminal 108 are input to the booster 98 via a smoothing circuit (not shown). The gate G of the first switching element 101, the gate G of the fourth switching element 104, the gate G of the second switching element 102, and the gate G of the third switching element 103 are collectively connected to the input / output unit of the control device 86, respectively. Will be done.
The first to fourth switching elements 101 to 104 conduct conduction between the drain D and the source S only when a control signal is input to the gate G. The current is different when the ON signal is input to the gate G of the first switching element 101 and the fourth switching element 104 and when the ON signal is input to the gate G of the second switching element 102 and the third switching element 103. The direction of is reversed.

The plasma device configured as described above is put into a drive state by turning on the start switch 88. By controlling the switching circuit 96, an AC voltage of 2 kHz or more is applied to the electrode portions 24 and 26 by the power supply device 16, and for example, an AC voltage of 8 kHz or more and 9 kHz or less can be applied. .. Further, nitrogen gas is supplied to the gas passages 34c and 36c at a desired flow rate, and the processing gas is supplied to the discharge space 21 at a desired flow rate. Further, the heating gas is supplied to the heating gas passage 62.

The processing gas is supplied to the discharge space 21 in the P direction, but in the gas passage 40 on the upstream side, a dielectric barrier discharge occurs between the electrode holders 34 and 36 via the electrode covers 34 and 36, and downstream thereof. In the discharge chamber 56 on the side, an arc discharge occurs between the lower ends 27s and 28s of the pair of electrode rods. Discharge is a state in which a high electric field is generated in the space between a pair of electrodes to cause dielectric breakdown in the gas existing in the space between the pair of electrodes (a state in which gas molecules are ionized and electrons and ions are increased. ) To allow current to flow between the pair of electrodes. Of these, the dielectric barrier discharge refers to the discharge that occurs when an AC voltage is applied to the pair of electrodes, and the arc discharge refers to the discharge that does not pass through the dielectric.

In dielectric barrier discharge, when an AC voltage is applied to the electrode holders 29 and 30, electric charges are stored in the electrode covers 34 and 36, but when the polarity is reversed, the stored electric charges are released. Causes a discharge. Further, the electrode covers 34 and 36 limit the current flowing between the electrode holders 29 and 30. Therefore, in the dielectric barrier discharge, it is usual that the arc discharge is not reached, and a large amount of energy is not usually applied to the processing gas. Further, in this embodiment, since a high frequency AC voltage is applied to the electrode holders 29 and 30, the polarity reversal speed becomes high and discharge can be satisfactorily generated.

On the other hand, in the arc discharge, a large current flows between the downstream end portions 27s and 28s of the pair of electrode rods 27 and 28, and a large amount of energy is applied to the processing gas.

As described above, in the dielectric barrier discharge, the energy applied to the processing gas is small, so that the processing gas is not always ionized and turned into plasma. However, the processing gas is put into a state of high energy potential (excited state or heated).
After that, since a large amount of energy is applied to the processing gas in the arc discharge, the processing gas that has not been plasmatized in the dielectric barrier discharge can be satisfactorily turned into plasma. Further, since the processing gas that has received the dielectric barrier discharge is already in a state of having a high energy potential, it becomes easier to generate plasma by receiving the arc discharge. It should be noted that the discharge occurs in both the portion of the discharge space 21 between the pair of electrode holders 34 and 36 and the portion between one end portions 27s and 28s of the pair of electrode rods. Was confirmed by being generated.

Further, in the present embodiment, the warm-up operation is performed when the start switch 88 is turned on, and after the warm-up operation is performed, the irradiation of plasma to the object to be processed is permitted. In the warm-up operation, a voltage is applied to the electrodes 24 and 26 to supply the heating gas as in the case where the plasma is irradiated to the object to be processed, but the plasma generation is unstable. Therefore, the plasma is not irradiated to the object to be treated. In this embodiment, as a notification of the warm-up operation, "during warm-up operation" indicating that the warm-up operation is in progress is displayed on the display 87. In other words, when the display 87 displays "warm-up operation", it is predetermined not to irradiate the object to be treated with plasma.

The warm-up operation is performed when the driving of the plasma device is started, that is, when the start switch 88 is turned on. Further, when the warm-up operation time has elapsed, the warm-up operation is terminated, but the operation of the plasma device is continued. After that, the plasma device may irradiate the object W to be processed with plasma. Further, when the stop switch 89 is turned ON during the warm-up operation, the warm-up operation is interrupted and the drive for plasma generation of the plasma device is stopped.

As a general rule, the warm-up operation time during which the warm-up operation is performed is the time when the plasma device immediately before the start switch 88 is continuously stopped when the start switch 88 is turned on. It is determined at a longer time than when it is short. On the other hand, there is a positive correlation between the temperature of the tip of the nozzle 80 and the capacity of the plasma device (whether or not plasma can be output stably), and the temperature of the tip of the nozzle 80 is high. In the case, it is known that the capacity of the plasma device is higher than that in the low case, and the plasma can be stably output. The temperature of the tip of the nozzle 80 is usually lower when the stop time Toff of the plasma device is long than when it is short. Further, when the temperature rise gradient during the warm-up operation is constant, the temperature at the tip of the nozzle 80 increases as the warm-up operation time becomes longer. From the above, in order to raise the temperature of the tip of the nozzle 80, which dropped while the plasma device was stopped, to a temperature at which the capacity of the plasma device becomes high due to the warm-up operation, the warm-up operation time , When the stop time is long, it is decided to be longer than when it is short.

Further, the warm-up operation time Tw is determined by multiplying the stop time Toff by the coefficient α (Tw = Toff × α). The coefficient α can be determined based on the state in which the temperature at the tip of the nozzle 80 is lowered in the stopped state of the plasma device and the state in which the temperature is raised during the warm-up operation. In this embodiment, the temperature rise gradient at the tip of the nozzle 80 during warm-up operation, the temperature decrease gradient at the tip of the nozzle 80 when the plasma device is stopped, etc. are simulated or actually measured by an external thermometer. The coefficient α is determined based on the data and the like.

However, when the start switch 88 is first turned on after the plasma device is switched from the undriveable state to the driveable state and the plasma device is started to be driven, the warm-up operation time Tw is predetermined. It is determined at the set time Th (Tw = Th). It is presumed that the plasma device was continuously stopped for a long time immediately before that. Therefore, it is considered that the temperature of the tip of the nozzle 80 of the plasma apparatus is approximately room temperature (for example, standard temperature). From the above, the set time Th is such that the temperature at the tip of the nozzle 80 of the plasma apparatus is stable from the standard temperature (for example, 24 ° C.) based on, for example, the temperature rise gradient during the warm-up operation described above. The time required for the temperature to rise to a temperature at which plasma can be irradiated is determined in advance by experiments, simulations, etc., and can be determined based on the determined time and the like.

On the other hand, even when the plasma device is in the driveable state, it may be in the stopped state continuously for a long time. In that case, the time obtained by multiplying the stop time Toff by the coefficient α (Toff × α). May be longer than the set time Th. In that case, the warm-up operation time Tw is set to the set time Th. This is because the need for warm-up operation for a longer time than the set time Th is low.
Hereinafter, the time (Toff × α) obtained by multiplying the stop time Toff by the coefficient α is referred to as a provisional warm-up operation time, and is determined based on at least one of the provisional warm-up operation time and the set time Th. The operation time is referred to as the main warm-up operation time.

Further, if the stop switch 89 is turned on during the warm-up operation, that is, between the start of the warm-up operation and the elapse of the main warm-up operation time, the interruption flag is set. The warm-up operation is interrupted and the drive for plasma generation of the plasma apparatus is stopped. After that, when the start switch 88 is turned on and the plasma device is started to be driven, the warm-up operation time is determined to be the set time Th. This is because the previous warm-up operation, in other words, the drive of the plasma device was insufficient, and it is desirable to sufficiently warm up. In this case, the warm-up operation time Tw is determined to be the set time Th regardless of the length of the stop time of the plasma apparatus.

The control of the warm-up operation is executed by the plasma device operation control program represented by the flowchart of FIG. The plasma device operation control program is executed at predetermined set times.
In step 1 (hereinafter, abbreviated as S1; the same applies to the other steps), it is determined whether or not the warm-up operation is in progress. When the warm-up operation is not in progress, it is determined in S2 and 3 whether or not the start switch 88 or the stop switch 89 is turned on. When the start switch 88 and the stop switch 89 are not turned on, S1 to 3 are repeatedly executed.

If the ON operation of the start switch 88 is performed in the meantime, the determination of S2 becomes YES, and the ON operation of the start switch 88 is first performed in S4 after the ON operation of the start switch 88 is switched from the undriveable state to the driveable state. It is determined whether or not the operation is performed. In the case of the first operation, in S5, the main warm-up operation time Tw is determined to be the set time Th (Tw = Th). Then, in S6 and S7, the warm-up operation of the plasma device is started, and "warming-up operation" is displayed on the display 87.

During the warm-up operation, the determination of S1 becomes YES, and in S8 and 9, it is determined whether or not the stop switch 89 has been turned on and whether or not the main warm-up operation time has elapsed. During the warm-up operation, all the determinations are NO, and S1, 8 and 9 are repeatedly executed. However, when the main warm-up operation time has elapsed, the determination of S9 is YES, and the display 87 is displayed in S10. "Warm-up operation" is erased.

While the plasma device is irradiating the object to be processed with plasma, S1 to 3 are repeatedly executed, but when the stop switch 89 is turned on, the determination of S3 is YES. In S11, the drive for plasma generation of the plasma apparatus is stopped, and in S12, the measurement of the stop time Tof is started.

While the plasma apparatus is stopped, S1 to 3 are repeatedly executed, and the stop time Tof is continuously measured. If the start switch 88 is turned on again in the meantime, the determination of S2 is YES and the determination of S4 is NO. Whether or not the interruption flag is ON is determined in S13, but if the determination in S13 is NO, the stop time Toff measured in S14 is read.

In S15, the provisional warm-up operation time Tws is obtained, and in S16, it is determined whether or not the provisional warm-up operation time Tws is longer than the set time Th. If the determination in S16 is NO, the main warm-up operation time is determined as the provisional warm-up operation time in S17 (Tw = Tws), and if the determination is YES, the main warm-up operation is in S18. The time is determined by the set time Th (Tw = Th).

Since the warm-up operation is in progress, S1, 8 and 9 are repeatedly executed as described above, but if the stop switch 89 is turned on during the warm-up operation, the determination of S8 is made. Is YES, the drive for plasma generation of the plasma device is stopped in S19, the interruption flag is turned ON in S20, and the display “Warm-up operation” on the display 87 is erased in S21.

Then, in the stopped state of the plasma device, S1 to S3 are repeatedly executed. Next, when the start switch 88 is turned on, the interruption flag is ON, so the determination of S13 is YES. Become. In this case, in S5, the main warm-up operation time is determined to be the set time Th, and the warm-up operation is performed in S6. Also, the interruption flag is turned off.

In the time chart shown in FIG. 8, at the time point t0, the plasma device is switched from the undriveable state to the driveable state. At time point t1, the start switch 88 is first turned on. The main warm-up operation time is determined as the set time (Tw = Th), and the warm-up operation is performed up to the time point t2.

The stop switch 89 is turned on at the time point t3, and the start switch 88 is turned on at the time point t4, but from the time the stop switch 89 is turned on until the next start switch 88 is turned on (time point t3 to time point t4). ), The stop time Toff is measured (Toff = Tfa). At the time point t4, the provisional warm-up operation time Tws is obtained, but since the provisional warm-up operation time Tws is equal to or less than the set time Th, the main warm-up operation time Tw is determined to be the provisional warm-up operation time Tws.

On the other hand, the stop switch 89 is turned ON at the time point t5, and then the start switch 88 is turned ON at the time point t6. The operation time Tws becomes longer than the set time Th. Therefore, the main warm-up operation time Tw in the warm-up operation started at the time point t6 is determined to be the set time Th.

Further, as shown in the time chart of FIG. 9, the warm-up operation is started from the time point t7, but the stop switch 89 is turned on at the time point t8 before the lapse of the main warm-up operation time Tw. Therefore, the warm-up operation is interrupted, and the drive for plasma generation of the plasma device is stopped. Next, the warm-up operation is started at the time point t9, and in that case, the main warm-up operation time Tw is determined to be the set time Th regardless of the stop time of the plasma apparatus.

As described above, in this embodiment, since the warm-up operation time is determined based on the continuous stop time of the plasma device before the start of the warm-up operation, the degree of decrease in the temperature of the plasma device is determined. Based on the above, the warm-up operation time can be determined to be an appropriate length. Further, the energy required for the warm-up operation time can be reduced as compared with the case where the warm-up operation time is always determined to be the set time Th. Further, the warm-up operation time can be easily determined based on the stop time of the plasma apparatus.

As described above, in this embodiment, the warm-up operation control unit is configured by a portion for storing the plasma device operation control program represented by the flowchart of FIG. 10 of the control device 86, a portion for executing the program, and the like. Of these, the part that stores S1, 3, 12, 14 to 17, the part that executes, etc. constitutes the first warm-up operation time determination unit, and the part that stores S1, 2, 4, 5, the part that executes, etc. The second warm-up operation time determination unit is configured by the above, and the third warm-up operation time determination unit is configured by the part for storing S1, 3, 12, 14 to 16, 18 and the part for executing, and S1,8, The fourth warm-up operation time determination unit is composed of a portion for storing 20, 13 and 5 and a portion for executing, and a provisional warm-up operation time determination unit is composed of a portion for storing S15 and a portion for executing S15. Further, the warm-up operation time determination unit is configured including the first to fourth warm-up operation time determination units and the like. Further, the portion for storing S6, the portion for executing S6, and the like correspond to the portion for controlling the heater 73 and the power supply device 16 in the warm-up operation. Further, the warm-up notification unit is configured by the display 87 and the like.

In the above embodiment, "during warm-up operation" is displayed on the display 87 as one aspect of the notification of warm-up operation, but the present invention is not limited to this. For example, a lamp, a buzzer, a voice output, or the like can be used to notify the start and end of the warm-up operation as a notification of the warm-up operation.

In addition, the content of warm-up operation does not matter. For example, it is possible to make only one of the application of the voltage to the pair of electrode portions 24 and 26 and the heating of the heating gas performed.

Further, in the above embodiment, the coefficient α is determined based on the stopped state of the plasma device, the lowered state of the temperature of the tip of the nozzle 80 during the warm-up operation, and the rising state. It can also be determined based on the temperature of the part of the device that has a positive correlation with the capacity of the plasma device. For example, the temperature in the discharge space, the temperature of the pair of electrode portions 24, 26, and the like correspond.

Further, the coefficient α and the set time Th can be set to different values or the same values for the nozzles 80, 83 and the like. Further, the structure of the plasma generation unit 12 does not matter. For example, either one of the dielectric barrier discharge and the arc discharge may be performed. In addition to the embodiments described in the above-described embodiment, the present disclosure includes various aspects based on the knowledge of those skilled in the art. It can be implemented in a modified or improved form.

12: Plasma generation part 14: Heating gas supply part 21: Discharge space 22: Dielectric surrounding member 24, 26: Electrode part 27, 28: Electrode rod 29, 30: Electrode holder 34, 36: Electrode cover 34c, 36c: Gas Passage 40: Gas passage 42, 44, 48: Gas passage 56: Discharge chamber 72: Gas pipe 73: Heater 86: Control device 88: Start switch 89: Stop switch

Claims (8)

A plasma device that irradiates an object to be processed with plasma.
The warm-up operation control unit that controls the warm-up operation performed when the driving of the plasma device is started is included.
When the warm-up operation control unit has a long stop time, which is the time during which the warm-up operation is performed, and the time during which the plasma device is continuously stopped immediately before the start of the drive. Is a plasma device that includes a warm-up time determination unit that determines a longer time than if it is short. When the drive is started after the drive of the plasma device is stopped by the warm-up operation time determining unit, the time obtained by multiplying the stop time by a coefficient is used as the warm-up operation time. A value that includes the first warm-up operation time determination unit to be determined, and the coefficient is determined based on the temperature decrease state of the plasma device in the stopped state of the plasma device and the temperature rise state during the warm-up operation. The plasma apparatus according to claim 1. When the drive is first started after the plasma device is switched from the undriveable state to the driveable state, the warm-up operation time determination unit further determines the warm-up operation time in advance. The plasma apparatus according to claim 1 or 2, which includes a second warm-up operation time determination unit that determines a set time. The warm-up operation time determination unit
When the drive is started after the drive of the plasma device is stopped, the time obtained by multiplying the stop time, which is the time in the stopped state, by a coefficient is provisionally the warm-up operation time. Temporary warm-up operation time determination unit to be determined, and
When the warm-up operation time tentatively determined by the provisional warm-up operation time determination unit is longer than the set time, the main warm-up operation time, which is the warm-up operation time, is determined as the set time. 3. The plasma apparatus according to claim 3, which includes a warm-up operation time determination unit. When the warm-up operation is interrupted, the warm-up operation time determining unit determines the warm-up operation time of the warm-up operation to be performed when the drive is started as the set time. The plasma apparatus according to claim 3 or 4, which includes a fourth warm-up operation time determination unit. The plasma device according to any one of claims 1 to 5, wherein the plasma device includes a warm-up notification unit for notifying the warm-up operation. The plasma device includes a power supply device that applies a voltage to each of a pair of electrode portions provided apart from each other.
The plasma device according to any one of claims 1 to 6, wherein the warm-up operation control unit controls the power supply device to apply a voltage to the pair of electrode units. The plasma device includes a heater for heating the heating gas, and the heating gas obtained by heating the heating gas by the heater is irradiated to the object to be processed together with the plasma.
The plasma device according to any one of claims 1 to 7, wherein the warm-up operation control unit heats the heater to the heating gas.

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