JP2005222779A - Plasma processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To widen a range of application of plasma processing by enabling to efficiently carry out the plasma processing by applying a pulse corona discharge, for example, by using a coaxial cylinder-shaped reactor having a linear electrode and a cylinder-shaped electrode. <P>SOLUTION: The plasma processing device 10 comprises a pulse power source 12 generating a high voltage pulse V<SB>L</SB>(or a high voltage pulse train Pc including the high voltage pulse V<SB>L</SB>) by the supply of a direct current input voltage Vin; and a reactor 16 connected to the pulse power source 12, promoting NOx treatment by the pulse corona discharge by generating a uniform streamer discharge area 14 by the high voltage pulse V<SB>L</SB>(or a high voltage pulse train Pc including high voltage pulse V<SB>L</SB>) generated at the pulse power source 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, various processes (gas decomposition process, deodorizing process, plasma film forming process, plasma etching process, laser oscillation process, gas generating process, etc.) are performed using plasma generated by the discharge of a high voltage pulse generated from a pulse power supply. It is related with the plasma processing apparatus which can perform.

  Recently, techniques for performing deodorization, sterilization, film formation, decomposition of harmful gases, and the like have been applied by plasma generated by discharge of a high-voltage pulse (see, for example, Patent Document 1 and Non-Patent Document 1). It has been found that it is necessary to supply a high voltage and a very narrow pulse in order to efficiently perform plasma processing (see, for example, Non-Patent Document 2).

  As a specific example of such a plasma processing apparatus, there is an exhaust gas purification apparatus for purifying NO in exhaust gas, for example. This device purifies NO by using an exhaust gas purification catalyst and a plasma reactor together. As a plasma reactor, one of a pair of electrodes is covered with a dielectric, and an alternating current is applied to the pair of electrodes. Is applied to generate barrier discharge to purify NO (see, for example, Patent Document 2).

Japanese Patent No. 2649340 Japanese Patent Laid-Open No. 6-106025 Applied Physics, Vol. 61, No. 10, 1992, p. 1039-1043, "Preparation of amorphous silicon thin film by high voltage pulsed discharge chemical vapor deposition" IEEE TRANSACTION ON PLASMIC SCIENCE, VOL.28, NO.2, APRIL 2000, p.434-442, “Improvement of NOx Removal Efficiency Using Short-Width Pulsed Power”

  By the way, it is known that the plasma treatment by the dielectric barrier discharge as described above is effective as a dry method of the NOx treatment, but the NOx treatment by the pulse corona discharge has been tried.

  In this NOx treatment by pulse corona discharge, it is considered to use a coaxial cylindrical reactor configured such that a linear electrode is surrounded by a cylindrical electrode. This is because by applying a positive pulse to the central linear electrode, there is an advantage that the electric field strength at the center is increased and a high-energy electron component is generated.

  However, the pulse supplied from the conventional pulse power supply is a pulse close to a sine wave. In this case, only the rising portion of the pulse waveform is directly related to the plasma processing, and the falling portion is wasted. A pulse close to a sine wave draws a gentle curve at both the rising and falling edges, which increases the wasted period and is disadvantageous in terms of efficiency.

  Further, when a pulse close to a sine wave is applied, a lightning-like discharge is locally generated, and the efficiency may be worse than the plasma treatment by the dielectric barrier discharge. Alternatively, even when streamer discharge occurs, there is a portion where the streamer is not locally generated, and this portion also causes a reduction in processing efficiency.

  The present invention has been made in consideration of such problems, and plasma processing by pulse corona discharge using, for example, a coaxial cylindrical reactor having a linear electrode and a cylindrical electrode can be efficiently performed. An object of the present invention is to provide a plasma processing apparatus capable of expanding the application range of processing.

The plasma processing apparatus according to the present invention includes a pulse power source that generates a high voltage pulse, and a reactor that is connected to the pulse power source and generates a discharge by the high voltage pulse generated by the pulse power source. Has a linear electrode connected to a pulse power source and a cylindrical electrode fixed at a constant potential, and the linear electrode is inserted into a hollow portion of the cylindrical electrode, and the pulse power source The high-voltage pulse generated in (1) has a voltage increase rate (dV / dt) at the time of rising of 10 ¹¹ (V / s) or more.

  That is, since a high voltage pulse with a steep rise is applied between the linear electrode and the cylindrical electrode, the electric field strength at the center of the hollow portion of the cylindrical electrode is increased, and a high-energy electron component is generated. It will be. Moreover, there is no local lightning-like discharge, and the plasma region generated in the reactor is distributed within the hollow portion of the cylindrical electrode and coaxially with the linear electrode. That is, in the hollow portion of the cylindrical electrode, a uniform streamer discharge region is generated from the linear electrode toward the cylindrical electrode.

  Thereby, plasma processing by pulse corona discharge using a reactor having a linear electrode and a cylindrical electrode can be performed efficiently, and the application range of plasma processing can be expanded.

Here, the plasma treatment includes, for example, gas decomposition treatment, deodorization treatment, plasma film formation treatment, plasma etching treatment, laser oscillation treatment, gas generation treatment, and the like, and is particularly suitable for NOx treatment by pulse corona discharge. In addition, formation of B ₄ C thin film, formation of Y-123 series thin film, formation of ZnS or ZnS: Mn thin film, metal filling in via hole for LSI (high integrated circuit) wiring, for example, preparation of AlN ultrafine particles, surface modification It can also be applied to quality.

  And in the said structure, it is preferable that the said high voltage pulse produced | generated by the said pulse power supply has a pulse half width of 50-100 ns. Usually, only the rising portion is directly involved in the plasma processing, and the falling portion is wasted. However, according to the present invention, the pulse waveform of the high voltage pulse output from the pulse power supply is an impulse pulse waveform with both steep rising and falling edges, so there is almost no wasted part, and plasma generated by the high voltage pulse is eliminated. Processing efficiency can be improved.

  Moreover, the said structure WHEREIN: It is preferable that the said cylindrical electrode has a cylindrical shape, and the said linear electrode is distribute | arranged on the same axis | shaft of the said cylindrical electrode. Thereby, the plasma area | region which generate | occur | produces in a reactor is distributed in the hollow part of a cylindrical cylindrical electrode, and on the same axis | shaft of a linear electrode. Therefore, plasma processing by pulse corona discharge using a coaxial cylindrical reactor can be performed efficiently, and the application range of plasma processing can be expanded.

  The pulse power supply is connected to an inductor, a first semiconductor switch and a second semiconductor switch connected in series between two input terminals to which a DC input voltage is applied, and an anode terminal of the first semiconductor switch. A diode having a cathode terminal connected to the other end of the inductor and an anode terminal connected to a gate terminal of the first semiconductor switch, the first semiconductor being turned on by the second semiconductor switch. The high voltage pulse may be generated in the inductor in accordance with accumulation of inductive energy in the inductor due to conduction of the switch and turn-off of the first semiconductor switch due to turn-off of the second semiconductor switch. .

  In this case, first, by turning on the second semiconductor switch, the first semiconductor switch is also turned on, a voltage of a DC power supply is applied to the inductor, and inductive energy is accumulated in the inductor. Thereafter, when the second semiconductor switch is turned off, the first semiconductor switch is also turned off rapidly, so that a very narrow high voltage pulse that rises very steeply is generated in the inductor.

  The inductor may include a primary winding and a secondary winding that is magnetically coupled to the primary winding and has a greater number of turns than the number of turns of the primary winding. . In this case, a voltage equal to or lower than the practical maximum withstand voltage of the first semiconductor switch is applied to the primary winding, the number of turns of the primary winding is N1, and the number of turns of the secondary winding is N2. At this time, the voltage generated in the secondary winding is N2 / N1 or more of the voltage applied to the primary winding.

That is, by using the pulse power supply, the voltage increase rate (dV / dt) at the time of rising is 10 ¹¹ (V / s) or more and the pulse half-value width is 50 to 100 ns from the pulse power supply. High voltage pulses can be output. This contributes to the fact that the plasma processing by pulse corona discharge can be efficiently performed and the application range of the plasma processing can be expanded.

  As described above, according to the plasma processing apparatus of the present invention, it is possible to efficiently perform plasma processing by pulse corona discharge using a reactor having a linear electrode and a cylindrical electrode (for example, a coaxial cylindrical reactor). In addition, the application range of plasma treatment can be expanded.

  Hereinafter, an embodiment in which the plasma processing apparatus according to the present invention is applied to, for example, NOx processing by pulse corona discharge will be described with reference to FIGS.

As shown in FIG. 1, the plasma processing apparatus 10 according to the present embodiment generates a high voltage pulse V _L (or a high voltage pulse train Pc including the high voltage pulse V _L ) by supplying a DC input voltage Vin. 12 and a high voltage pulse V _L (or a high voltage pulse train Pc including the high voltage pulse V _L ) generated by the pulse power supply 12 and connected to the pulse power supply 12 to generate a uniform streamer discharge region 14. And a reactor 16 that promotes NOx treatment by pulse corona discharge.

  The reactor 16 includes a linear electrode 18 connected to the pulse power supply 12 and a cylindrical electrode 20 connected to GND (ground). The linear electrode 18 is inserted into the hollow portion 22 of the cylindrical electrode 20. Has been configured.

  The linear electrode 18 has a diameter of about 0.5 mm, a length of about 500 mm, and is made of stainless steel. In addition, a corrosion-resistant conductive material such as Inconel can be used as the material. The cylindrical electrode 20 has a cylindrical shape, has an inner diameter of about 76 mm, a length of about 500 mm, and is made of stainless steel. In addition, a corrosion-resistant conductive material such as Inconel can be used as the material. That is, the reactor 16 has a so-called coaxial cylindrical shape in which the linear electrode 18 is inserted coaxially with the cylindrical electrode 20 at the central portion of the hollow portion 22 of the cylindrical electrode 20 having a cylindrical shape.

As shown in FIG. 2, the high voltage pulse V _L (or the high voltage pulse train Pc including the high voltage pulse V _L ) output from the pulse power source 12 has a pulse half-value width Tp of 50 to 100 ns, The voltage increase rate (dV / dt) is set to 10 ¹¹ (V / s) or more.

  Here, the NOx process by pulse corona discharge in the plasma processing apparatus 10 according to the present embodiment will be described.

When a high voltage pulse V _L (or a high voltage pulse train Pc including the high voltage pulse V _L ) is applied to the linear electrode 18, the reactor 16 has a coaxial cylindrical structure, so that the electric field strength at the center portion becomes very large. A high energy electronic component is generated. In the present embodiment, the output voltage (peak value) of the high voltage pulse _VL is about 42 kV, and the current (peak value) is about 138A. The reaction gas is N ₂ : O ₂ : H ₂ O: NO = 90%: 5%: 4%: 200 ppm, and the pressure is 1 × 10 ⁵ Pa. The gas flow rate is 2.0 liters / minute.

  As a result of observing the discharge phenomenon in the hollow portion 22 of the cylindrical electrode 20, it was observed that a uniform streamer discharge region 14 was generated from the linear electrode 18 toward the cylindrical electrode 20.

  Usually, in order to decompose NOx gas and convert it into non-toxic gas, high energy electrons that can collide with NOx gas molecules and cause dissociation are required. For that purpose, it is important to generate a large amount of electrons having energy larger than the dissociation energy of gas molecules.

In the present embodiment, when a high voltage pulse V _L (or a high voltage pulse train Pc including the high voltage pulse V _L ) is applied between the linear electrode 18 and the cylindrical electrode 20, as described above, from the linear electrode 18. A uniform streamer discharge region 14 is generated toward the cylindrical electrode 20. The streamer discharge has a very high electric field strength at the tip portion (outer peripheral portion) in the discharge region 14, and the electrons are accelerated while progressing toward the linear electrode 18 to generate high energy electrons. . This high energy electron directly dissociates NOx and converts it into a nontoxic gas. In this case, a large amount of NOx gas can be processed because of the large electric power.

Thus, in the plasma processing apparatus 10 according to the present embodiment, the reactor 16 having the linear electrode 18 and the cylindrical electrode 20 has a voltage increase rate (dV / dt) at the time of startup of 10 ¹¹ (V / s). ) Since the high voltage pulse V _L (or the high voltage pulse train Pc including the high voltage pulse V _L ) having a steep rise as described above is applied, the electric field strength at the center portion of the hollow portion 22 in the cylindrical electrode 20 is increased. It becomes large and a high energy electronic component will be produced | generated. Moreover, no lightning-like discharge is locally generated, and the plasma region generated in the reactor 16 is distributed in the hollow portion 22 of the cylindrical electrode 20 and coaxially with the linear electrode 18. To do. That is, in the hollow portion 22 of the cylindrical electrode 20, the uniform streamer discharge region 14 is generated from the linear electrode 18 toward the cylindrical electrode 20.

  Thereby, NOx treatment by pulse corona discharge using the reactor 16 having the linear electrode 18 and the cylindrical electrode 20 can be efficiently performed, and the application range of the NOx treatment can be expanded.

Next, a specific configuration of the pulse power supply 12 that generates a high voltage pulse having a pulse half-width Tp of 50 to 100 ns and a voltage increase rate (dV / dt) at the time of rising of 10 ¹¹ (V / s) or more is illustrated. 3 to 4E will be described.

  As shown in FIG. 3, the pulse power supply 12 includes a high voltage pulse generation circuit 30 and a drive signal generation circuit 32.

  In the high voltage pulse generation circuit 30, a capacitor 38 is connected in parallel between two input terminals 34 and 36 to which a DC input voltage Vin is applied. Further, an inductor 40, a second capacitor 38 is connected between the two input terminals 34 and 36. One semiconductor switch 42 and second semiconductor switch 44 are connected in series. Of both ends of the inductor 40, the anode terminal side of the first semiconductor switch 42 is referred to as one end 46, and one input terminal (positive electrode) 34 side is referred to as the other end 48.

In the high voltage pulse generation circuit 30, a diode 50 is inserted and connected between the other end 48 of the inductor 40 and the control terminal (gate) G of the first semiconductor switch 42 so that the control terminal G side becomes an anode. Furthermore, a reactor 16 that requires a high voltage pulse V _L is connected in parallel with the inductor 40.

  In the example of FIG. 3, the second semiconductor switch 44 is provided on the other input terminal (negative electrode) 36 side, but it goes without saying that the same effect can be obtained even if it is provided on the one input terminal (positive electrode) 34 side. Nor. The reactor 16 may also be connected in parallel with the first semiconductor switch 42 instead of in parallel with the inductor 40.

  In the example of FIG. 3, the second semiconductor switch 44 includes a power metal oxide semiconductor field effect transistor (hereinafter referred to as a power MOSFET) 54 in which an avalanche diode 52 is incorporated. A drive signal Vc is supplied from the drive signal generation circuit 32 to the gate terminal of the power MOSFET 54.

  In the example of FIG. 3, the first semiconductor switch 42 uses an SI thyristor that has a very high withstand voltage increase rate (dV / dt) at turn-off and a high voltage rating.

In the example of FIG. 3, the drive signal Vc output from the drive signal generation circuit 32 is used as a pulse train, so that a plurality of high voltage pulses V _L are transmitted from the high voltage pulse generation circuit 30 to the drive signal Vc. A high voltage pulse train Pc generated according to the pulse train is output.

As shown in FIG. 2, the high voltage pulse train Pc output from the high voltage pulse generation circuit 30 has a pulse half width Tp of 50 to 100 ns and a voltage increase rate (dV / dt) at the time of rise of 10 ¹¹ (V / S) or higher voltage pulse V _L is a pulse train output at a constant period. The repetition frequency fc of the high voltage pulse train Pc is 1 Hz or more.

  The repetition frequency fc of the high voltage pulse train Pc can be changed by appropriately changing the output timing of the drive signal Vc, that is, the timing at which the second semiconductor switch 44 is turned on. The drive signal Vc is output as a voltage signal of 15 V, for example, when the second semiconductor switch 44 is turned on.

Here, with reference to the circuit diagram of FIG. 3 and the operation waveform diagrams of FIGS. 4A to 4E regarding the passage of time during which the high voltage pulse generation circuit 30 in the pulse power supply 12 supplies the high voltage pulse V _L to the reactor 16. While explaining.

First, at time t ₀ , the drive signal Vc (see FIG. 4E) is supplied from the drive signal generating circuit 32 to the gate terminal of the power MOSFET 54, and the power MOSFET 54 is turned on from off (see FIG. 4D).

  At this time, the first semiconductor switch 42 is turned on by the electric field effect applied between the gate G and the cathode K due to the extremely large impedance of the reverse polarity of the diode 50. Since the rise of the anode current of the first semiconductor switch 42 is suppressed by the inductor 40, normal turn-on is performed only by the field effect. Needless to say, a gate current may be positively supplied to the gate G of the first semiconductor switch 42 through a resistor connected in parallel with the diode 50 or through a resistor.

In this way, when the second semiconductor switch 44 and the first semiconductor switch 42 are turned on at time t ₀ , a voltage substantially the same as the DC input voltage Vin is applied to the inductor 40, and the inductance of the inductor 40 is L. as shown in FIG. 4A, the current I _L in inductor 40 increases linearly with time at a gradient Vin / L.

The current I _L, the current Ip at the time _{t 1 (= VinT 0 / L} ) , and the the desired electromagnetic energy (= LIp ^2/2) is obtained, the supply of the driving signal Vc from the driving signal generation circuit 32 And the power MOSFET 54 is turned off (see FIG. 4E).

At this time, if the floating inductance (not shown) other than the inductor 40 existing in the current I _L flow path is large (mainly wiring inductance), the power MOSFET 54 is not instantaneously cut off, and the current continues to flow slightly. When there is time, the output capacitance of the power MOSFET 54 is charged, and when the avalanche voltage of the diode 52 is reached, the diode 52 conducts with the avalanche voltage and generates a large loss. For this reason, the stray inductance is reduced as much as possible so that the diode 52 does not reach the avalanche and an almost ideal turn-off is performed.

When the power MOSFET 54 is turned off, the current from the cathode K of the first semiconductor switch 42 is also zero, that is, an open state, so that the current I _L flowing through the inductor 40 is cut off, and the inductor 40 has residual electromagnetic energy. Although an attempt to generate a reverse induction voltage by the diode 50 acts, the current I _L in inductor 40, the anode of the anode a → gate G → diode 50 of the first semiconductor switch 42 of the first semiconductor switch 42 → Commutates to the cathode path of the diode 50.

  In this case, it is necessary to consider that the stray inductance of the branch circuit in which the diode 50 exists is as low as possible and that commutation is completed in a short time. In the first semiconductor switch 42, charges are accumulated by the current that has flown until now, and until the charge becomes zero (storage period), the anode A-gate G of the first semiconductor switch 42 is not connected. In order to maintain the conduction state, the voltage drop in the path is small.

Accordingly, since the reverse induced voltage V _L of the inductor 40 can be suppressed to a sufficiently low value, the said although little decrease in the current I _L, said period between T ₁ of the inside (T ₁ of the FIG. 4A) short storage period of time the This is determined by the amount of charge drawn from the gate G of one semiconductor switch 42. Therefore, (in the case of the example of FIG. 3, or the anode current is not allowed to flow) as large as possible, current steeply flow, shorten the period T ₁ to turn-off gain apparent as 1 or less, decrease in the current I _L in inductor 40 It is necessary to suppress as much as possible.

At the time t ₂ , the extraction of the charge accumulated in the first semiconductor switch 42 is completed, the depletion layer spreads from the cathode K side and the gate G side to the anode A side, and a turn-off operation is started. The depletion layer has an amount determined by the built-in potential, so that the voltage applied to the junction increases, expands as turn-off progresses, and finally reaches the vicinity of the anode A.

Therefore, the electric capacity due to the depletion layer changes from a saturated state (conducting state) where many active charges exist to a small amount of electric capacity determined by the structure. A current due to the electromagnetic energy of the inductor 40 continues to flow from the anode A to the gate G to charge the capacitance of the depletion layer. This charging voltage, that is, the voltage V _AG between the anode A and the gate G of the first semiconductor switch 42, rises relatively slowly due to a large electric capacity at first, but rapidly rises with the spread of the depletion layer. To go.

When the current I _L becomes zero at the time point t ₃ , the voltages V _AG and V _L become maximum and become V _AP and V _LP , respectively, as shown in FIGS. 4B and 4C. At this time, all of the electromagnetic energy of the inductor 40 has shifted to the capacitance of the depletion layer of the first semiconductor switch 42.

Furthermore, this phenomenon are the resonant operation by the inductance and capacitance of the first semiconductor switch 42 of the inductor 40, substantially current I _L of the inductor 40 is a cosine waveform, the anode of the first semiconductor switch 42 A- gate The voltage V _AG between G has a sine waveform.

Accordingly, by selecting the inductance value of the inductor 40 whose constant can be freely determined, the pulse half width Tp of the high voltage pulse V _L generated in the inductor 40 and the reactor 16 in parallel with the inductor 40 can be controlled. That is, if the equivalent capacitance of the electric capacity of the first semiconductor switch 42 is C, the pulse half width Tp is

となる。

It becomes.

The electric charge stored in the electric capacity of the depletion layer of the first semiconductor switch 42 charged to the maximum value V _AP at the time point t ₃ is a diode that is conductive in the reverse direction by the inductor 40 and the accumulated electric charge due to the continuation of the resonance phenomenon. 50 route discharge begins in the diode 50 is reverse recovery at time t _4, it continues until the non-conductive. If energy remains in the capacitance of the depletion layer of the inductor 40 and the first semiconductor switch 42 at the time point t ₄ , the current due to this energy is converted from the capacitor 38 → the diode 52 of the second semiconductor switch 44 → the first The semiconductor switch 42 flows through a path from the cathode K to the anode A.

During the period T ₄ flowing through the capacitor 38, a regenerative operation is performed, and the energy remaining in the electric capacity of the depletion layer of the inductor 40 and the first semiconductor switch 42 is regenerated, which greatly contributes to the improvement of the operation efficiency. Therefore, it is important to shorten the reverse recovery time of the diode 50 as much as possible and to shorten the period T ₃ .

  In the above description, the reactor 16 has been described as having a linearity such as a resistive load. However, if the reactor 16 has a non-linearity such as a discharge gap, the load impedance rapidly decreases while the voltage is rising, and the subsequent waveform is It may be different from FIGS. 4A to 4E.

  By the way, in the pulse power supply 12 shown in FIG. 3, the voltage between the anode A and the cathode K of the first semiconductor switch 42 is substantially the same as the voltage of the inductor 40. A voltage exceeding the withstand voltage of the voltage between K cannot be output in a pulse by the inductor 40.

  Therefore, the pulse power supply 12a according to the modification shown in FIG. 5 is suitable when it is desired to output a voltage in the inductor 40 that is higher than the withstand voltage of the voltage between the anode A and the cathode K of the first semiconductor switch 42.

  First, as shown in FIG. 5, the pulse power source 12 a according to this modification has substantially the same configuration as the pulse power source 12 shown in FIG. 3, but the inductor 40 includes the primary winding 70 and the primary winding. It differs in that it has a secondary winding 72 that is magnetically coupled to the wire 70 and has more turns than the primary winding 70.

  In this modification, it is preferable to wind the magnetic core around the magnetic core in order to close the magnetic coupling between the primary winding 70 and the secondary winding 72 and suppress the generation of leakage magnetic flux.

If the number of turns of the primary winding 70 is N1, and the number of turns of the secondary winding 72 is N2, in the case of the pulse power source 12a according to the modification, a high voltage pulse of V _AG × (N2 / N1) V _L can be output to the reactor 16.

  As described above, each of the pulse power supplies 12 and 12a may be a single first semiconductor switch 42 as a semiconductor switch to which a high voltage is applied, and is normally used for driving the gate of the first semiconductor switch 42. There is no need for a gate drive circuit with an electronic circuit.

  In addition, since the high voltage of each pulse power source 12 and 12a is generated or supplied only by the anode A of the first semiconductor switch 42 and one end 46 of the inductor 40, other circuits of the pulse power sources 12 and 12a are provided. All elements can be low voltage circuit components. Therefore, it is possible to operate even from a DC input voltage Vin of about 12V, and it is sufficient that the voltage rating of the component is several tens of volts.

Then, the high voltage pulse V _L (or the high voltage pulse train Pc including the high voltage pulse V _L ) is supplied to the linear electrode 18 of the reactor 16, whereby the space between the inner wall of the cylindrical electrode 20 and the linear electrode 18. As a result, discharge occurs, and plasma is generated in the hollow portion 22 of the cylindrical electrode 20.

  As a result, as described above, the generation of the plasma causes NOx to be directly dissociated and converted into a non-toxic gas.

In the above-described example, an example in which NOx treatment by pulse corona discharge is applied as plasma treatment has been shown. However, for example, gas decomposition treatment, deodorization treatment, plasma film formation treatment, plasma etching treatment, laser oscillation treatment, gas generation treatment For example, formation of a B ₄ C thin film, formation of a Y-123 series thin film, formation of a ZnS or ZnS: Mn thin film, metal embedding in a wiring via hole of an LSI (high integrated circuit), for example, It can also be applied to production of AlN ultrafine particles, surface modification, and the like.

  The plasma processing apparatus according to the present invention is not limited to the above-described embodiment, but can of course have various configurations without departing from the gist of the present invention.

It is a block diagram which shows the plasma processing apparatus which concerns on this Embodiment. It is a wave form diagram which shows the high voltage pulse train output from a pulse power supply. It is a circuit diagram which shows a pulse power supply. 4A to 4E are diagrams for explaining operation waveforms of voltages and currents of respective parts of the pulse power supply shown in FIG. It is a circuit diagram which shows the modification of a pulse power supply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a ... Plasma processing apparatus 12 ... Pulse power supply 14 ... Streamer discharge area 16 ... Reactor 18 ... Linear electrode 20 ... Cylindrical electrode 22 ... Hollow part 30 ... High voltage pulse generation circuit 40 ... Inductor 42 ... First semiconductor switch 44 ... Second semiconductor switch 50 ... Diode

Claims (6)

A pulse power supply that generates high voltage pulses;
A reactor connected to the pulse power source and generating a discharge by a high voltage pulse generated by the pulse power source;
The reactor includes a linear electrode connected to a pulse power source and a cylindrical electrode fixed at a constant potential, and the linear electrode is inserted into a hollow portion of the cylindrical electrode,
The plasma processing apparatus, wherein the high voltage pulse generated by the pulse power source has a voltage increase rate (dV / dt) at the time of rising of 10 ¹¹ (V / s) or more. The plasma processing apparatus according to claim 1,
The plasma processing apparatus, wherein the high voltage pulse generated by the pulse power source has a pulse half width of 50 to 100 ns. The plasma processing apparatus according to claim 1 or 2,
The cylindrical electrode has a cylindrical shape,
The plasma processing apparatus, wherein the linear electrode is arranged coaxially with the cylindrical electrode. In the plasma processing apparatus of any one of Claims 1-3,
A plasma region generated in the reactor by application of a high voltage pulse from the pulse power supply to the reactor is distributed in the hollow portion of the cylindrical electrode and coaxially with the linear electrode. Plasma processing equipment. In the plasma processing apparatus of any one of Claims 1-4,
The pulse power supply is
An inductor, a first semiconductor switch, and a second semiconductor switch connected in series between two input terminals to which a DC input voltage is applied;
A diode having a cathode terminal connected to the other end of the inductor connected to the anode terminal of the first semiconductor switch, and an anode terminal connected to the gate terminal of the first semiconductor switch;
Accumulation of inductive energy in the inductor due to conduction of the first semiconductor switch by turning on the second semiconductor switch;
The plasma processing apparatus, wherein the high voltage pulse is generated in the inductor when the first semiconductor switch is turned off by turning off the second semiconductor switch. The plasma processing apparatus according to claim 5, wherein
The inductor has a primary winding and a secondary winding that is magnetically coupled to the primary winding and has a greater number of turns than the number of turns of the primary winding;
Applying a voltage below the practical maximum withstand voltage of the first semiconductor switch to the primary winding,
When the number of turns of the primary winding is N1, and the number of turns of the secondary winding is N2,
The plasma processing apparatus, wherein a voltage generated in the secondary winding is N2 / N1 or more of a voltage applied to the primary winding.

Images