JP3773510B2 - Discharge plasma processing method and discharge plasma processing apparatus - Google Patents

Description

  The present invention relates to a discharge plasma processing method in which a plastic sheet or the like is subjected to surface modification such as hydrophilic treatment, surface treatment such as etching or CVD, and in particular, plasma is generated by glow discharge under pressure conditions near atmospheric pressure. The present invention relates to a discharge plasma processing method and a discharge plasma processing apparatus for performing plasma processing on a surface of an object to be processed.

Conventionally, as an apparatus for performing this type of discharge treatment, a glow discharge plasma processing apparatus described in Patent Document 1 includes a counter electrode, a solid dielectric disposed on at least one counter surface of the counter electrode, and a gap between the pair of electrodes. A high voltage pulse power supply adapted to apply a pulsed electric field, a high voltage pulse power supply capable of supplying a high voltage direct current, and a turn-on time and a turn-off time of 500 ns or less The semiconductor device includes a pulse control unit that converts the high-voltage direct current into a high-voltage pulse. Thus, the apparatus can realize a high voltage and high speed pulse voltage having an electric field strength of 1 to 100 kV / cm and a pulse rise time and fall time of 100 μS or less.
Japanese Patent No. 3040358 (Claims)

  By the way, the glow discharge plasma processing apparatus having the above structure is capable of continuously generating uniform glow discharge plasma under a pressure in the vicinity of atmospheric pressure and stably performing the surface treatment of the substrate. The voltage applied was 0 V when the discharge was terminated and the discharge was stopped. When a discharge is generated for the next treatment, the voltage is suddenly increased from 0 V to the discharge treatment voltage, and at that time, a voltage or current that cannot be obtained during normal discharge flows, and a load is applied to the electrode or power source. As a result, the dielectric breakdown of the solid dielectric and the breakdown of the element are induced, so that there is a problem that the life of the electrode is shortened as compared with the continuous treatment.

  That is, the voltage from 0V to about 15000V is applied between the opposing electrodes at the moment when the switch is turned on in order to establish a discharge, and a large current suddenly tries to flow through the electronic circuit or the discharge part. An inertial force acts on the current flow, and a current that does not normally flow flows. Furthermore, the electric field is generated where the load is electrically weak in the power supply element, where the distance between the electrodes is locally small, where electrons are present, where there is variation in the thickness of the dielectric or in the dielectric constant. There was a problem of local concentration, causing dielectric breakdown in that part, and abnormal discharge.

  The present invention has been made in view of such problems, and an object of the present invention is to extend the life of the opposing electrodes that perform discharge plasma treatment and to apply a voltage to the electrodes. An object of the present invention is to provide a discharge plasma processing method capable of preventing abnormal current from flowing through an electric circuit and capable of efficiently plasma-processing a plurality of objects to be processed. It is another object of the present invention to provide a discharge plasma processing method and a discharge plasma processing apparatus capable of extending the life of an electrode and preventing failure of an electric circuit that applies a discharge processing voltage to the electrode.

In order to achieve the above object, a discharge plasma processing method according to the present invention comprises a pair of opposing electrodes whose at least one electrode facing surface is coated with a solid dielectric, and a discharge processing voltage is applied between the electrodes. A method of performing plasma processing on an object to be processed by discharging and generating plasma, wherein a discharge is generated between electrodes lower than the discharge processing voltage as a pre-process and / or a post-process of a plasma processing process for applying a discharge processing voltage. No discharge preparation voltage is applied between the electrodes. That is, in the plasma treatment process, a high voltage is applied between the electrodes, but a standby state in which a low voltage is applied is created as a previous process. This discharge plasma treatment method is preferably performed under a pressure near atmospheric pressure, and the applied discharge treatment voltage is preferably a pulsed voltage.

  In the discharge plasma processing method of the present invention configured as described above, the object to be processed is subjected to surface treatment or the like between the electrodes facing each other or in the vicinity of the plasma outlet near the outside of the electrodes. When a treatment voltage is applied to cause discharge on the workpiece, the discharge voltage control means applies a discharge preparation voltage that is lower than the discharge treatment voltage and does not cause a discharge between the electrodes before starting discharge, and enters a standby state. After that, since the discharge treatment voltage is applied to start the discharge, a state in which electrons can easily fly before the plasma treatment, that is, a channel can be formed in advance to prevent dielectric breakdown of the solid dielectric and the like of the electrode. Consumption can be prevented, the durability of the apparatus can be improved, and abnormal current can be prevented from flowing in an electric circuit that applies a voltage between the electrodes.

  In addition, a discharge preparation voltage lower than the discharge treatment voltage is applied between the electrodes as a subsequent step of the discharge treatment step, and a low voltage that does not cause a discharge after the discharge treatment is applied. According to this configuration, since the discharge preparation voltage is lower than the discharge treatment voltage without dropping the voltage from the high voltage subjected to the discharge treatment to 0 V at a stretch, the dielectric breakdown of the solid dielectric is prevented and the durability of the electrode is reduced. Performance can be improved, the electrical elements of the electrical circuit can be prevented from being destroyed, and the durability of the apparatus can be improved.

  Another aspect of the discharge plasma processing method according to the present invention is a method of plasma processing a plurality of objects to be processed by the above-described discharge plasma processing method, wherein the objects to be processed are sequentially installed between electrodes as a pre-process. A process of plasma-treating a workpiece placed between the electrodes, and a step of removing the workpiece after the plasma treatment as a post-process. In the installation step and / or the removal step, a discharge preparation voltage is provided. Is applied between the electrodes. According to this configuration, in addition to the effects similar to the above, particularly in the case of batch processing in which the same plasma processing is continuously performed on a plurality of objects to be processed, the electrode consumption is low and the efficiency is high. Discharge plasma treatment is possible.

  Moreover, as a preferable specific aspect of the discharge plasma processing method according to the present invention, the discharge preparation voltage is set to 10 to 99.9% of the discharge processing voltage. If it is less than 10%, the effect as a standby voltage is low, and a large current flows at the start of discharge, and if it exceeds 99.9%, a discharge is generated and the standby state cannot be established. In particular, it is preferable to set the discharge preparation voltage to a voltage of 70 to 95% of the discharge processing voltage. By setting the discharge preparation voltage in this way, it is possible to prevent the electrode from being consumed, to prevent an abnormal current in the electric circuit, and to improve the durability of the apparatus.

  Furthermore, the discharge plasma processing apparatus according to the present invention includes a pair of opposing electrodes in which at least one electrode facing surface is coated with a solid dielectric, and a discharge processing voltage is applied between the electrodes to discharge the plasma. An apparatus for generating a plasma treatment of an object to be processed, the apparatus comprising a discharge voltage control means, the control means being lower than the discharge treatment voltage before and / or after applying the discharge treatment voltage. It is characterized by controlling the application of a discharge preparation voltage at which no discharge occurs.

According to this structure, before starting the discharge and performing the plasma treatment, or after applying the discharge plasma treatment, by applying a low voltage discharge preparation voltage that does not cause a discharge between the electrodes, the electrons can be made to fly easily. In other words, by making the channel in advance, rapid changes in voltage and current can be suppressed, so that dielectric breakdown of the solid dielectric and element breakdown can be suppressed, resulting in suppression of abnormal discharge and the like. , Life is also prolonged. Thereby, since stable discharge plasma processing can be performed, the surface modification of the object to be processed becomes uniform, and the running cost can be reduced.

  According to the discharge plasma processing method and the discharge plasma processing apparatus of the present invention, in order to apply a high voltage for processing after applying a discharge preparation voltage lower than the discharge processing voltage and causing no discharge when performing the discharge plasma processing, Electrode consumption can be reduced, and durability of the discharge plasma processing apparatus can be improved. In addition, since the discharge preparatory voltage is returned to the low discharge preparatory voltage after the discharge plasma treatment, it is possible to prevent a sudden interruption of the current, to suppress the consumption of the electrode, and to perform the plasma treatment continuously and uniformly again. Plasma processing can be performed with little electrode consumption, and batch processing can be performed particularly efficiently.

  Hereinafter, an example of a glow discharge plasma processing apparatus will be described in detail with reference to the drawings as an embodiment of an apparatus for performing the discharge plasma processing method according to the present invention. FIG. 1 is a configuration diagram of a main part of a glow discharge plasma processing apparatus according to the present embodiment. In FIG. 1, a glow discharge plasma processing apparatus (hereinafter referred to as a plasma processing apparatus) 10 is an apparatus that performs a modification process that imparts hydrophilicity, water repellency, etc. to the surface of an object to be processed such as a resin sheet. A pair of parallel plate type electrodes 11 and 12 are arranged facing each other in the vertical direction. The electrodes 11 and 12 are made of, for example, a single metal such as copper or aluminum, an alloy such as stainless steel or brass, an intermetallic compound, and the like. It is configured to be constant. At least one electrode facing surface of the electrodes 11 and 12 is covered with a solid dielectric such as alumina. In this embodiment, solid dielectrics 13 and 14 are formed on the facing surfaces of both electrodes, and a space between them is formed. It is configured as a discharge space 15.

  The solid dielectrics 13 and 14 are in close contact with the installed electrodes 11 and 12 and are covered so as to completely cover the electrodes. In the present embodiment, an alumina coating layer is used as the solid dielectric, and the thickness of the solid dielectrics 13 and 14 is preferably about 0.01 to 4 mm. If the thickness is too thick, a high voltage is required to cause discharge. However, if it is too thin, dielectric breakdown may occur when a voltage is applied, and arc discharge may occur. The solid dielectric may be a plate or sheet such as ceramics or resin, or may be a film. The distance between the electrodes 11 and 12 is set in consideration of the thickness of the solid dielectric, the magnitude of the applied voltage, the type of processing gas, the purpose of using plasma, etc., but is preferably about 1 to 20 mm. If it is less than 1 mm, it is difficult to place an object to be processed within the interval, and if it exceeds 20 mm, it is difficult to generate uniform discharge plasma.

  As the material of the solid dielectric, in addition to the above-mentioned alumina, for example, plastics such as polytetrafluoroethylene and polyethylene terephthalate, metal oxides such as glass, silicon dioxide, zirconium dioxide, and titanium dioxide, and composites such as barium titanate are used. Various oxides such as oxides and multilayers thereof can be used. The solid dielectric preferably has a relative dielectric constant of 2 or more (in the environment of 25 ° C., the same shall apply hereinafter).

  Specific examples of the dielectric having a relative dielectric constant of 2 or more include polytetrafluoroethylene, glass, and metal oxide film. In order to stably generate a high-density discharge plasma, it is preferable to use a fixed dielectric having a relative dielectric constant of 10 or more. The upper limit of the relative dielectric constant is not particularly limited, but an actual material of about 18500 is known. The solid dielectric having a relative dielectric constant of 10 or more is composed of a metal oxide film mixed with 5 to 50% by weight of titanium oxide and 50 to 95% by weight of aluminum oxide, or a metal oxide film containing zirconium oxide. It is preferable to use a film having a thickness of 10 to 1000 μm.

Discharge space 1 between the solid dielectric 13 of the upper electrode 11 and the solid dielectric 14 of the lower electrode 12
No. 5 has a configuration in which a processing gas flows. That is, the gas introduction container 16 is installed on the left side of the discharge space, and the gas discharge container 17 is installed on the right side. For example, a cylinder (not shown) of a processing gas containing nitrogen gas is connected to the gas introduction container 16, and the outlet of the container is directed to the discharge space 15. The gas discharge container 17 has a suction port located toward the discharge space 15, and sucks the processing gas supplied to the discharge space 15 and discards it in a disposal cylinder or an exhaust gas treatment device (not shown). It is configured.

  The upper and lower electrodes 11, 12, the gas introduction container 16 and the gas discharge container 17 may be covered with the container 18. The material of the container 18 is preferably resin or glass, but metal can be used as long as it is insulated from the electrode. The processing gas is preferably supplied uniformly to the discharge space 15. When using a plurality of types of processing gas or when processing is performed in a mixed gas of processing gas and dilution gas, the processing gas does not become non-uniform during supply. It is preferable that Further, it is preferable that the processing gas blow-out port and the suction port are slit or porous. Note that the processing gas may be supplied by being sprayed at a high pressure.

  The discharge space 15 is supplied with a resin sheet 19 as an object to be processed in contact with the solid dielectric 14 of the lower electrode 12. That is, the resin sheet 19 is supplied from the unwinding roll 19a, is plasma-treated in the processing apparatus 10, and is then wound up by the winding roll 19b. When a processing gas is flowed from the gas introduction container 16 and a discharge processing voltage is applied between the upper and lower electrodes 11 and 12, glow discharge is generated in the discharge space 15, and discharge plasma is generated in this space between the electrodes. A modification treatment can be performed on the surface of the resin sheet 19 positioned.

  In the plasma processing apparatus 10, the resin sheet 19 is processed at a site that is in contact with the generated discharge plasma. Therefore, in the example of FIG. 1, the upper surface of the resin sheet 19 that is the object to be processed is plasma processed. When it is desired to perform treatment on both surfaces of the resin sheet, the resin sheet 19 may be lifted from the lower electrode 12. The glow discharge plasma treatment of this embodiment may be performed by heating or cooling the resin sheet 19, but can also be performed at room temperature. The time required for the glow discharge plasma processing is appropriately determined in consideration of the applied voltage, the type of processing gas, the ratio in the mixed gas, and the like.

  In the plasma processing apparatus 10 of the present embodiment, for example, a pulsed voltage is applied between the electrodes 11 and 12 by the power supply circuit 20 shown in FIG. The power supply circuit 20 includes a pulse oscillation circuit 21 that generates a pulse signal having a predetermined frequency, a switching inverter circuit 22 to which the pulse signal is input, a + DC power supply circuit 23 that supplies positive power and negative power to the switching inverter circuit, and −DC And a power supply circuit 24. The output signal from the switching inverter circuit 22 is amplified by the step-up transformer 25 and output from the output terminal 26 as the discharge processing voltage VH, and the other end of the step-up transformer is grounded.

  As shown in FIG. 1, the pulsed discharge processing voltage output from the power supply circuit 20 is, for example, an upper portion of the plasma processing apparatus 10 via a controller 27 as a means for controlling the voltage applied between the electrodes 11 and 12. Applied to the electrode 11, the lower electrode 12 is grounded. The controller 27 adjusts the voltage of the pulse signal and can arbitrarily set Vpp. In this embodiment, Vpp can be lowered within a range of 10 to 99.9% to be the discharge preparation voltage VL, and the adjusted voltage is applied between the electrodes 11 and 12 as a pre-process of the discharge treatment process. In addition, it is applied between the electrodes 11 and 12 as a subsequent process of the discharge treatment process. The reason why the voltage range is set is that if the voltage is set to 10% or less, the standby voltage at the preparation stage is not effective, and if it is 99.9% or more, the discharge is started without entering the standby state. is there. More preferably, the discharge preparation voltage VL is set to 70 to 95% of the discharge processing voltage VH.

  FIG. 3 shows the pulsed discharge processing voltage VH output from the power supply circuit 20. Note that positive and negative voltages ± v indicated by broken lines indicate voltages at which discharge starts when a voltage Vpp exceeding this range is applied. The pulse voltage formed by the power supply circuit 20 is an impulse type having a voltage rise time of 100 μs or less, an electric field strength of about 1 to 100 kV / cm, and a frequency of 0.5 kHz to 100 kHz as shown in FIG. ing. As the pulse-like voltage waveform, an appropriate waveform such as a square wave type or a modulation type can be used in addition to the illustrated impulse type. Further, in FIG. 3, although the voltage application is repeated positive and negative, a so-called one-wave waveform in which a voltage is applied to either the positive or negative polarity side may be used. A bipolar waveform may also be used.

  Although the pulsed voltage waveform output from the power supply circuit 20 is not limited to the waveform mentioned here, the shorter the pulse rise time, the more efficiently the ionization of the gas during plasma generation. When the rise time of the pulse exceeds 100 μs, the discharge state tends to shift to an arc and becomes unstable, and a high-density plasma state due to the pulse voltage cannot be expected. In addition, the rise time is preferably fast, but there is a limitation on an apparatus that generates an electric field intensity that is large enough to generate plasma at normal pressure and that has a fast rise time, and in reality it is 40 ns. It is difficult to achieve a pulse voltage with a rise time less than. More preferably, the rise time is 50 ns to 5 μs. Here, the rise time refers to a time during which the voltage change is continuously positive.

  Further, the fall time of the pulse voltage is preferably steep, and is preferably 100 μs or less, which is the same as the rise time. In the power supply circuit 20 used in this embodiment, the rise time and the rise time are substantially the same. Set to time. Furthermore, modulation may be performed using pulses having different pulse waveforms, rise times, and frequencies. The frequency of the pulse voltage is preferably 0.5 kHz to 100 kHz. If it is less than 0.5 kHz, the plasma density is low, so that the process takes too much time. If it exceeds 100 kHz, arc discharge tends to occur. More preferably, the frequency is 1 kHz or more. By applying such a high-frequency pulse voltage, the processing speed of the plasma processing can be greatly improved.

  Moreover, it is preferable that the pulse duration in a pulse-form voltage is 1-1000 microseconds. If it is less than 1 μs, the discharge becomes unstable, and if it exceeds 1000 μs, it tends to shift to arc discharge. More preferably, it is 3 μs to 200 μs. Here, although one pulse duration is indicated as t in FIG. 3, it means the time for which pulses continue in a pulse voltage consisting of repetition of ON and OFF.

  The magnitude of the peak voltage Vpp of the pulsed discharge processing voltage VH shown in FIG. 3 is determined as appropriate, but in the present embodiment, the electric field strength between the electrodes is in the range of 1 to 100 kV / cm. If it is less than 1 kV / cm, the process takes too much time, and if it exceeds 100 kV / cm, arc discharge tends to occur. In addition, direct current may be superimposed when applying a pulsed voltage. In the present invention, the pulsed discharge processing voltage VH can be adjusted by the controller 27 so that the peak voltage Vpp is in the range of 10 to 99.9%. , 12 are applied. 4a shows a non-energized state in which no voltage is applied between the electrodes, FIG. 4b shows a standby state in which a discharge preparation voltage VL with a voltage of about 50% is applied, and FIG. 4c shows a discharge processing voltage VH of 100%. The processing state to which is applied is shown.

The operation of the discharge plasma processing by the plasma processing apparatus 10 configured as described above will be described below with reference to FIG. FIG. 4A shows a state where no electric field is applied between the electrodes in the first state, and the power supply circuit 20 does not output. When performing the plasma treatment, the resin sheet 19 that is the object to be treated is positioned between the electrodes 11 and 12, and the discharge preparation voltage VL (for example, about 50% of the discharge treatment voltage VH lower than the discharge treatment voltage VH is not generated. FIG. 4B) is applied between the electrodes 11 and 12 as a pre-process of the plasma treatment. In this state, no discharge is generated between the upper electrode 11 and the resin sheet 19, and electrons are likely to fly, that is, a channel is formed. This standby state is preferably continued for about 0.1 to 5 seconds.

  After this standby state, when a discharge treatment voltage VH (FIG. 4c) is applied between the electrodes 11 and 12, a discharge is generated between the resin sheet 19 and the upper electrode 11, and the modification treatment by the plasma treatment of the resin sheet 19 is performed. Done. The plasma treatment time varies depending on various conditions as described above, but is preferably about 1 to 5 seconds. When the process is stopped in the middle or when the process is completed, a discharge preparation voltage VL (FIG. 4b) of about 50% of the discharge process voltage VH is applied between the electrodes in a low voltage application process as a subsequent process of the plasma process. To the standby state, and the plasma-treated resin sheet 19 is conveyed. After the resin sheet 19 is transported, the next resin sheet is positioned between the electrodes and the discharge plasma treatment is performed. At this time, since no discharge is generated between the electrodes, a channel is formed. Abnormal current does not flow between the electrodes, and consumption of the electrodes can be prevented.

  An example in which plasma processing is performed by the discharge plasma processing method of the present invention and a comparative example in which plasma processing is performed by a conventional discharge plasma processing method will be described.

  The electrode size was 150 mm long, 150 mm wide, and 20 mm thick on both the application side and the ground side, and four sides of the opposing surface were chamfered with R = 10 mm. A temperature control medium flow path (not shown) was formed inside the electrode and set to 35 ° C. Stainless steel (SUS430J2) was used as the electrode substrate, alumina coating (t = 1 mm) was used as the dielectric, and the distance between the electrodes was set to 2 mm. Nitrogen gas was flowed at 30 slm as the processing gas. The discharge conditions were a frequency of 15 kHz, a discharge treatment voltage VH of 15.0 kVpp (discharge start 14.5 kVpp), a discharge preparation voltage VL during discharge standby of 13.5 kVpp, and about 93% of the discharge treatment voltage VH. Under the above conditions, the discharge treatment voltage VH was applied for 5 seconds to discharge, the discharge plasma treatment was performed, and then the discharge preparation voltage VL was applied for 5 seconds to enter a standby state. When the insulation resistance of the dielectric after the end of the cycle was measured, a decrease in insulation resistance could not be confirmed.

  As a comparative example, the discharge plasma treatment was started by applying a voltage of 15 kHz, a discharge treatment voltage VH, and 15.0 kVpp suddenly without providing a discharge ready state, i.e., a standby state, with a non-discharge voltage of 0 kVpp. As a result of processing under these conditions, abnormal discharge began to occur from about 50,000 cycles, and after 100,000 cycles, the insulation resistance of the solid dielectric decreased to 2% of the initial resistance value. In this state, glow discharge is not stable, and abnormal discharge such as arc discharge may occur, and uniform plasma treatment is impossible.

  Another embodiment of the present invention will be described in detail with reference to FIG. FIG. 5 is an explanatory view of the processing operation of another embodiment of the discharge plasma processing method according to the present invention. In addition, this embodiment is characterized in that a plurality of objects to be processed are batch-processed continuously by the above-described discharge plasma processing method as compared with the above-described embodiment.

In FIG. 5, the discharge plasma processing apparatus 30 includes a lower electrode 31 and an electrode 32 that is positioned above and moves on the electrode 31 with an interval. The space between the electrodes 31 and 32 is a discharge space, and the work 35 as a workpiece is placed and placed on the lower electrode 31, and the upper electrode 32 moves and discharges between the electrodes 31 and 32. Plasma treatment in space. A pulse voltage is applied between the electrodes from the power supply circuit, and glow discharge is generated.
In this embodiment, the plasma space is configured to move as the upper electrode 32 moves. Although not shown, a gas inlet and a gas outlet are installed in the discharge space so that the processing gas flows.

  On the left side of the plasma processing apparatus 30, unprocessed resin workpieces 35 are stacked and placed on a base 36, and the workpieces are placed one by one on the electrode 31 of the plasma processing apparatus 30 by the transfer device 40. Installed. Plasma treatment is performed by applying a discharge treatment voltage VH between the electrodes on the discharge plasma treatment apparatus 30. For example, the surface is subjected to water repellent treatment or hydrophilic treatment, and then removed from the electrode 31 by the right transport device 41. And stacked on the workpiece mounting table 37. When performing such batch processing, the plasma processing apparatus 30 transports and installs the workpiece 35 in a standby state to which the discharge preparation voltage VL is applied, and waits for the discharge preparation voltage VL to be applied even during transport and removal after the processing. State. As the transfer devices 40 and 41, a device having an appropriate form such as a device that adsorbs and conveys the workpiece 35 with a negative pressure, a device that conveys the workpiece 35 with an arm, and the like can be applied.

  That is, the discharge plasma processing method of this embodiment includes a step of sequentially placing the work 35 between the electrodes as a pre-process of the plasma processing step, a step of plasma-treating the work 35 disposed between the electrodes, and a plasma as a post-process. And a step of removing the workpiece 35 after processing, and in the step of installing and removing the workpiece 35, a discharge preparation voltage VL is applied between the electrodes. The discharge preparation voltage VL is also set to a voltage of 10 to 99.9% which is lower than the discharge processing voltage VH and does not cause discharge between the electrodes as in the above-described embodiment, and in particular, 70 to 95 of the discharge processing voltage. It is preferable to set the voltage to%.

  In the operation of this embodiment, as a first step, the work 35 is lifted by the transfer device 40, turned to place the work 35 on the lower electrode 31, and the transfer device 40 returns. After the work 35 is installed, a discharge preparation voltage VL is applied between the electrodes 31 and 32, and a discharge treatment voltage VH is applied as a second process to form a discharge state. The upper electrode 32 is moved to move the entire work 35. Plasma treatment is performed on the surface to return the upper electrode 32 to its original position and the plasma treatment is completed. The work 35 on the lower electrode 31 treated as the third step is lifted by the transfer device 41 and swung to remove it. Stacked on the workpiece mounting table 37. The processes of the plurality of workpieces 35 can be continuously performed by repeating the first to third steps.

  In this embodiment, during the first and third steps for conveying the workpiece 35, that is, in the installation step and the removal step, the discharge is stopped and the standby state in which the discharge preparation voltage VL (FIG. 4b) is applied is set. When the plasma treatment is performed by applying the discharge treatment voltage VH (FIG. 4c) in the step 2, it is possible to make it easy for electrons to fly. As described above, when the discharge processing voltage VH is applied in the plasma processing step, the channel is formed in advance in the standby state in which the discharge preparation voltage VL is applied in the installation step of the previous step. The change is suppressed, and it is possible to prevent an overshooted excessive current from flowing as in the case of applying a high voltage suddenly from the conventional 0V, and it is possible to prevent dielectric breakdown of the solid dielectric of the electrode and breakdown of the electric element.

  In addition, since the discharge preparation voltage VL is applied in the subsequent removal step after the plasma treatment, the voltage is not suddenly changed from 0 V as in the conventional case, so that the consumption of the electrodes can be prevented and the failure of the power supply circuit can be prevented. And since the plasma processing of the workpiece | work conveyed next can be performed efficiently continuously, the efficient process of the surface modification of the workpiece | work by plasma processing is attained. In addition, in this embodiment, it was set as the structure which one electrode which opposes moved, However, When an electrode does not move, an installation process is performed by installing so that a workpiece | work may be inserted between electrodes.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention described in the claims. Design changes can be made. For example, the controller that adjusts the peak voltage Vpp of the pulse voltage applied to the electrodes may function in a switching inverter circuit, a + DC power supply circuit, or a −DC power supply circuit. Moreover, although the example of the same voltage was shown by the pre-process and a post process as the discharge preparatory voltage applied by the pre process of a discharge treatment process, and a post process, you may use a different voltage by the process before and behind. Furthermore, although the example of the pulse-shaped voltage was shown as a voltage applied between electrodes, a continuous wave may be sufficient.

The principal part block diagram of one Embodiment of the discharge plasma processing apparatus which enforces the discharge plasma processing method which concerns on this invention. FIG. 2 is a block diagram of a power supply circuit that applies a pulsed voltage to the discharge plasma processing apparatus of FIG. 1. The figure which shows the pulse-shaped voltage output with the power supply circuit of FIG. The operation | movement of a discharge plasma processing method is shown, (a) is a figure which shows a non-energized state, (b) is a figure which shows the voltage of a discharge preparation state, (c) is a figure which shows the voltage of a discharge processing state. Operation | movement explanatory drawing which shows the process of batch processing as other embodiment of the discharge plasma processing method which concerns on this invention.

Explanation of symbols

  10, 30: glow discharge plasma processing apparatus, 11, 12, 31, 32: electrode, 13, 14: solid dielectric, 15: discharge space, 16: gas introduction container, 17: gas discharge container, 19: resin sheet ( Processing object), 20: power supply circuit (electric circuit), 27: controller (voltage control means), 30: work (processing object), 40, 41: transfer device, VL: discharge preparation voltage, VH: discharge processing voltage

Claims (5)

At least one electrode facing surface is provided with a pair of facing electrodes coated with a solid dielectric, and a discharge treatment voltage is applied between the electrodes under a pressure near atmospheric pressure to generate glow discharge and generate plasma. A discharge plasma treatment method for plasma-treating an object to be treated,
As a pre-process of the plasma treatment step of intermittently or continuously applying the discharge treatment voltage, a discharge preparation voltage lower than the discharge treatment voltage and not resulting in a glow discharge is intermittently or continuously applied between the electrodes. A characteristic discharge plasma treatment method. A method of plasma processing a plurality of objects to be processed by the discharge plasma processing method according to claim 1,
The step of sequentially placing the object to be treated between the electrodes as the pre-process, the step of plasma-treating the object to be treated disposed between the electrodes, and removing the object to be treated after the plasma treatment as the post-process A discharge plasma treatment method, wherein, in the installation step, the discharge preparation voltage is applied between the electrodes.   The discharge plasma processing method according to claim 1 or 2, wherein the discharge preparation voltage is set to 10 to 99.9% of the discharge processing voltage.   The discharge plasma processing method according to claim 1 or 2, wherein the discharge preparation voltage is set to 70 to 95% of the discharge processing voltage. At least one electrode facing surface is provided with a pair of facing electrodes coated with a solid dielectric, and a discharge treatment voltage is applied between the electrodes under a pressure near atmospheric pressure to generate glow discharge and generate plasma. A discharge plasma processing apparatus for plasma processing an object to be processed,
The processing apparatus includes means for controlling a voltage applied to the electrode, and the voltage control means does not reach a glow discharge lower than the discharge processing voltage before intermittent or continuous application of the discharge processing voltage. A discharge plasma processing apparatus that performs intermittent or continuous application control of a discharge preparation voltage.

Images