JP2007026781A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device capable of exerting a high treatment speed without causing damages to the surface of a sample. <P>SOLUTION: In the plasma treatment device 1, an alternating voltage of a phase θ1 is impressed onto a first impressing electrode 4 from a first power supply 2, the alternating voltage of the phase θ2 is impressed onto a second impressing electrode 5 from a second power supply 3, and a phase delaying means 8 measures the phase θ1 and the phase θ2, and based on the measurement result, controls movement of the first and the second power supplies 2, 3 so that a phase difference Δθ of the phase θ1 and the phase θ2 will become π(2k+1) [k is integer]. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus.

  A processing apparatus using plasma is widely used as an apparatus for performing surface treatments such as etching, film formation, ashing, and surface hydrophilization in manufacturing a multilayer structure of various devices such as semiconductors and liquid crystal display devices. In recent years, among plasma processing equipment, atmospheric pressure plasma processing is used to generate samples at a pressure near atmospheric pressure for the purpose of speeding up processing, reducing the cost of the equipment, and reducing the area occupied by the equipment. Equipment has been developed.

  As one of the atmospheric pressure plasma processing apparatuses, a power source, an application electrode to which a voltage output from the power source is applied, and a ground electrode provided so as to face and ground the application electrode with an insulator interposed therebetween The application electrode, insulator and ground electrode are combined into an electrode unit, the electrode unit is opposed to the sample, and a high-pressure reaction gas region including atmospheric pressure is formed between the electrode unit and the sample. An apparatus has been proposed in which high-pressure plasma based on a reaction gas is generated only in a region close to the sample between the electrode and the ground electrode, and the sample is processed by active species generated in the high-pressure plasma (for example, Patent Documents). 1).

  FIG. 8 is a schematic diagram showing a configuration of a conventional high-pressure plasma processing apparatus 100. Hereinafter, a conventional high-pressure plasma apparatus 100 will be described with reference to FIG. The high-pressure plasma apparatus 100 includes an inner electrode 101 that is an application electrode, an outer electrode 102 that is a ground electrode, an insulator 103 that insulates the inner electrode 101 and the outer electrode 102, and a voltage that is applied to the inner electrode 101 (not shown). Power source, a gas supply means for supplying a reaction gas, and a sample stage 105 on which a sample 104 as an object to be processed is placed.

  The inner electrode 101, the outer electrode 102, and the insulator 103 constitute an electrode floating type high voltage floating electrode 106. The electrode floating type high voltage floating electrode 106 and the sample 104 placed on the sample stage 105 are: It arrange | positions so that it may oppose in a predetermined gas atmosphere. The inner electrode 101, the outer electrode 102, and the insulator 103 each have a shape extending elongated in the direction perpendicular to the paper surface of FIG. Configure.

  The electrode floating type high-pressure levitation electrode 106 includes a high-pressure reaction gas supply port 107 that supplies a high-pressure reaction gas supplied from the reaction gas supply means toward the surface to be processed of the sample 104, and a reaction gas to be processed of the sample 104 A reaction gas exhaust port 108 for exhausting from the surface is formed.

  In the high-pressure plasma processing apparatus 100, when a high-pressure reaction gas is supplied from the reaction gas supply means to the high-pressure reaction gas supply port 107, a reaction gas flow 109 from the high-pressure reaction gas supply port 107 toward the reaction gas exhaust port 108 or the surrounding gas atmosphere is generated. The electrode-floating type high-pressure levitation electrode 106 is levitated by a distance D by the differential pressure between the pressure of the high-pressure reaction gas formed and supplied and the pressure of the surrounding gas atmosphere. Since this distance D is narrow, the reaction gas flow path through which the reaction gas flow 109 formed in the portion sandwiched between the electrode floating high voltage floating electrode 106 and the sample 104 becomes a low conductance gas flow path, and the electrode floating high pressure A high-pressure reaction gas region is formed in a portion sandwiched between the floating electrode 106 and the sample 104. The pressure in the high-pressure reaction gas region may be atmospheric pressure.

  It should be noted that the reactive gas flow 109 is formed even if the electrode floating type high voltage floating electrode 106 is not floated with respect to the sample 104, that is, even if both are arranged close to each other so that the distance D becomes a very small gap. The reaction gas channel thus formed becomes a gas channel having a low conductance, and a high-pressure reaction gas region can be formed in a portion sandwiched between the electrode floating type high-pressure floating electrode 106 and the sample 104.

  When a voltage is applied from the power source to the inner electrode 101, a circuit is formed in which power is supplied from the inner electrode 101 to the outer electrode 102 across the insulator 103 at the end surface on the side where the insulator 103 faces the sample 104. The Since the circuit portion to which power is supplied across the insulator 103 is formed in the reaction gas flow path without a conductor, it will be referred to as a power transmission circuit open end 110 for convenience.

  Of the high-pressure reactive gas region formed between the electrode-floating type high-pressure levitation electrode 106 and the sample 104, the inner electrode 101 and the outer electrode 102 are straddled across the insulator 103 by applying a voltage from the power source to the inner electrode 101. At the open end 110 of the power transmission circuit formed between the two, a local high-pressure plasma 111 is generated, and the active species generated by the high-pressure plasma 111 form, process, and treat the surface of the sample 104. Perform plasma treatment. Further, the entire surface to be processed of the sample 104 is processed by relatively moving the sample 104 and the electrode floating type high voltage floating electrode 106 in a substantially horizontal direction indicated by an arrow 112.

  In the high-pressure plasma apparatus 100, high-pressure plasma 111 is not generated between the inner electrode 101 and the sample 104 but is generated between the inner electrode 101 and the outer electrode 102 and generated in the high-pressure plasma 111. Since active species are diffused on the surface of the sample 104 to perform film formation, processing, surface treatment, and the like, plasma is not in direct contact with the sample 104 and the sample 104 is not damaged.

  However, the high-pressure plasma processing apparatus 100 disclosed in Patent Document 1 has the following problems. For example, the electric field strength when a voltage of 1.0 kV is applied to the inner electrode 101 of the high-pressure plasma processing apparatus 100 is illustrated. FIG. 9 is a diagram showing the calculation position of the electric field strength, and FIG. 10 is a diagram showing the calculation result of the electric field strength distribution.

  When obtaining the electric field intensity distribution, the horizontal direction is the X axis, the direction perpendicular to the surface 104a of the sample 104 is the Y axis, the surface 104a is the origin (zero) of the Y axis, and the XY axis The direction perpendicular to the paper surface of FIG. In addition, this XYZ axial direction is used in common in this specification.

  The distance D formed by the surface 104a to be processed of the sample 104 and the surface of the electrode floating type high-voltage levitation electrode 106 facing the surface to be processed 104a is 4.0 mm, the thickness of the insulator 103, that is, the inner electrode 101 and the outer electrode 102 The separation distance was set to be 3.0 mm. The insulator 103 is made of alumina (relative permittivity εr = 9.4), and a portion of the insulator 103 that separates the inner electrode 101 and the outer electrode 102 has a height of 3.5 mm and a base of 7.0 mm. The electric field strength was determined on the assumption that the cross section had a triangular depression.

  The electric field strength was determined for the following three regions. A region U sandwiched between the inner electrode 101 and the sample 104, a region V sandwiched between the insulator 103 and the sample 104, and a region V formed with the triangular depression, and a region sandwiched between the outer electrode 102 and the sample 104 W. In FIG. 10, lines 115 a and 115 b indicate the electric field strength in the region U, the line 116 indicates the electric field strength in the region V, and the line 117 indicates the electric field strength in the region W. The line 115 indicating the electric field strength in the region U is divided into two having an intermittent portion when the distance in the Y-axis direction is 4.0 mm, and the electric field strength in the space in the reaction gas flow path and the inner electrode 101. This is because the electric field strength in the inside changes discontinuously.

  The largest electric field strength of 6.4E5 [V / m] is generated in the region V, that is, the deep part Y = 7.5 mm of the depression. An electric field strength of 2.2E5 [V / m] is generated in the vicinity of the processing surface 104a in the region U, and an electric field strength of 0.06 [V / m] is generated in the vicinity of the processing surface 104a in the region W. .

  By increasing the voltage applied to the inner electrode 101, atmospheric pressure plasma corresponding to the reaction gas is generated in the region V where the highest electric field strength is generated, that is, the depression of the insulator 103, and is generated in the atmospheric pressure plasma. With the activated species, film formation, processing, surface treatment, and the like are performed on the surface 104a to be processed. When the input power to the inner electrode 101, that is, the applied voltage is increased to increase the plasma processing speed, the decomposition of the atmospheric pressure plasma generated between the inner electrode 101 and the outer electrode 102 is promoted, and at the same time, the region U The electric field strength in the vicinity of the surface to be processed 104a also increases. Finally, atmospheric pressure plasma is also generated on the surface to be processed 104a of the sample 104, and the atmospheric pressure plasma directly contacts the surface to be processed 104a. There is a problem of damaging the surface to be processed 104a.

  On the contrary, since the limit of the voltage that can be applied to the inner electrode 101 is regulated to such an extent that atmospheric pressure plasma is not generated on the surface of the sample 104, the upper limit of input power is defined, and a high processing speed is achieved. Have the problem of not being able to.

  From the result of obtaining the electric field strength, if the highest electric field strength in the vicinity of the inner electrode 101 is Ep and the highest electric field strength on the surface to be processed 104a which is the surface of the sample 104 is Es, the ratio between them: Ep / Es is 6.4E5 / 2.2E5 = 2.9 times. Therefore, the voltage applied to the inner electrode 101 is increased, and the voltage that is 2.9 times the voltage applied when atmospheric pressure plasma is generated in the portion of the highest electric field strength Ep between the regions U to W is increased to the inner side. When applied to the electrode 101, the portion showing the highest electric field strength Es on the surface to be processed 104a also increases to 2.9 times the electric field strength, so that the electric field intensity generated by the plasma is reached also on the surface to be processed 104a. It shows that atmospheric pressure plasma is generated on the surface and damages the surface of the sample 104.

JP 2000-306848 A

  An object of the present invention is to provide a plasma processing apparatus capable of exhibiting a high processing speed without damaging the surface of a sample.

The present invention includes a power source, an application electrode to which an alternating voltage output from the power source is applied, and a ground electrode provided so as to face and ground the application electrode with an insulator interposed therebetween, An electrode unit composed of an insulator and a ground electrode is arranged so as to face the sample, a reactive gas is locally supplied to the space formed by the electrode unit and the sample, and an alternating voltage is applied to the applied electrode. A plasma processing apparatus for generating plasma on a surface of the electrode unit facing the sample, and processing, film-forming, and surface-treating the sample with the plasma,
The application electrode includes two first application electrodes and a second application electrode,
Applied from the power supply so that the phase difference between the phase of the alternating voltage applied to the first application electrode and the phase of the alternating voltage applied to the second application electrode is π (2k + 1), where k is an integer. The plasma processing apparatus is characterized in that an alternating voltage is applied to the electrodes.

The present invention also provides a voltage branching unit that branches the alternating voltage output from the power source into a first transmission circuit connected to the first application electrode and a second transmission circuit connected to the second application electrode;
The phase of the alternating voltage applied to the second application electrode provided in the second transmission circuit is π (2k + 1) [where k is an integer] with respect to the phase of the alternating voltage applied to the first application electrode. And phase delay means for delaying.

The present invention also provides a voltage branching unit that branches the alternating voltage output from the power source into a first transmission circuit connected to the first application electrode and a second transmission circuit connected to the second application electrode;
M [where m is a positive integer] first dielectric group provided in the first transmission circuit;
And n [where n is a positive integer] second dielectric group provided in the second transmission circuit,
The dielectric constant of the i-th dielectric material (where i is a positive integer and i ≦ m) included in the first dielectric group is ε1i, the magnetic permeability is μ1i, and the length in the direction in which the first transmission circuit extends is L1i. ,
The dielectric constant of the portion where the first dielectric group of the first transmission circuit is not provided is ε10, the magnetic permeability is μ10, the length in the direction in which the first transmission circuit extends is L10,
The dielectric constant of the jth [j is a positive integer and j ≦ n] dielectric included in the second dielectric group is ε2j, the magnetic permeability is μ2j, and the length in the direction in which the second transmission circuit extends is L2j. ,
The dielectric constant of the portion where the second dielectric group of the second transmission circuit is not provided is ε20, the magnetic permeability is μ20, and the length in the direction in which the second transmission circuit extends is L20,
Let f be the frequency of the alternating voltage,
When the phase of the alternating voltage applied to the first application electrode is θ1, and the phase of the alternating voltage applied to the second application electrode is θ2,
An alternating voltage is applied to the first and second application electrodes so that the following expression is satisfied.

  According to the present invention, a high electric field intensity is generated in the vicinity of the electrode without damaging the surface of the sample, thereby generating an atmospheric pressure plasma having a high decomposition rate and active species density, thereby having a high processing speed. A plasma processing apparatus can be realized.

  FIG. 1 is a diagram showing a simplified configuration of a plasma processing apparatus 1 according to a first embodiment of the present invention. The plasma processing apparatus 1 generally includes two first and second power sources 2 and 3 and two first and second application electrodes to which alternating voltages output from the first and second power sources 2 and 3 are applied, respectively. 4, 5, a ground electrode 7 provided so as to be opposed to and grounded with the insulator 6 between the first application electrode 4 and the second application electrode 5, and the first application electrode 4 from the first power supply 2. So that the phase difference between the phase of the alternating voltage applied to and the phase of the alternating voltage applied to the second application electrode 5 from the second power supply 3 is π (2k + 1) [where k is an integer] Phase delay means 8 for delaying the phase of the other alternating voltage with respect to the phase of the other alternating voltage. The first and second application electrodes 4, 5, the insulator 6, and the ground electrode 7 constitute an electrode unit 9.

  In the plasma processing apparatus 1, the electrode unit 9 is disposed so as to face the sample 10, and a reactive gas is locally supplied to a space 11 (hereinafter referred to as a processing space 11) formed by the electrode unit 9 and the sample 10. Then, by applying an alternating voltage to the first application electrode 4 and the second application electrode 5, plasma is generated on the surface of the electrode unit 9 facing the sample 10, and processing, film formation, and surface of the sample 10 are generated by the plasma. It is used for processing.

  The first power source 2 and the second power source 3 are power sources capable of oscillating, for example, low frequency power, high frequency power, VHF power, microwave power, and the like, and both generate an alternating voltage having a frequency f [Hz]. The waveform of the alternating voltage of frequency f generated from the first power supply 2 and the second power supply 3 is a substantially sine waveform. When the first power supply 2 and the second power supply 3 oscillate high frequency power, VHF power, or microwave power, an impedance matching device that performs impedance matching is also included in the power supply. The alternating voltage generated by the first power source 2 is applied to the first application electrode 4 through the first transmission circuit 12, and the alternating voltage generated by the second power source 3 is applied to the second application electrode 5 through the second transmission circuit 13. To be applied.

  The phase θ1 of the alternating voltage applied from the first power supply 2 to the first application electrode 4 through the first transmission circuit 12 is applied to the second application electrode 5 from the second power supply 3 through the second transmission circuit 13. The phase θ2 of the alternating voltage is measured by a phase measuring device 14 that is electrically connected to the first and second transmission circuits 12 and 13. The phase measurement result by the phase measuring device 14 is input to the phase adjusting device 15, and the phase adjusting device 15 is connected to the first and second power sources 2 and 3. The phase adjuster 15 adjusts the phase so that a predetermined phase delay is generated between the phase θ1 and the phase θ2. This phase adjustment will be described in detail later. Therefore, the phase measuring device 14 and the phase adjuster 15 constitute the phase delay means 8.

  The first and second application electrodes 4 and 5 are electrodes having an elongated plate shape that is elongated in a direction perpendicular to the paper surface of FIG. 1, and are formed of, for example, a copper alloy. The first application electrode 4 and the second application electrode 5 are alternately arranged to face each other through the insulator 6a in a direction orthogonal to the long longitudinal direction (in this embodiment, the first application electrode 1 4 and 3 second application electrodes 5 are arranged 4). A ground electrode 7 is disposed via the insulator 6 on both outer sides in the arrangement direction in which the first and second application electrodes 4 and 5 are alternately disposed.

  The ground electrode 7 is provided so as to face the first and second application electrodes 4 and 5 in the arrangement direction of the first and second application electrodes 4 and 5. One of the ground electrodes 7 is supplied with a reaction gas through one of the ground electrodes 7a in a direction perpendicular to the surface 10a to be processed, which is a surface facing the electrode unit 9 and on which the sample 10 is subjected to plasma processing. A hole 16 is formed, and an opening to the processing space 11 facing the processing surface 10a of the reaction gas supply hole 16 constitutes the reaction gas supply port 16a. The other ground electrode 7b opposite to the one ground electrode 7a is formed with a reaction gas exhaust hole 17 penetrating in a direction perpendicular to the surface to be processed 10a. The opening to the processing space 11 that faces the reaction gas exhaust port 17a.

  The electrode unit 9 including the first and second application electrodes 4 and 5, the insulators 6 and 6 a, and the ground electrode 7, and the sample 10 are accommodated in, for example, a chamber and arranged in a predetermined gas atmosphere. The

  The electrode unit 9 and the sample 10 are arranged so as to have a gap G and can be moved relative to each other. A reaction gas supply source (not shown) is connected to the reaction gas supply hole 16 of one ground electrode 7a, and the reaction gas is supplied from the reaction gas supply source 16 through the reaction gas supply hole 16 to the processing space 11 from the reaction gas supply source. By exhausting the reaction gas from the reaction gas exhaust port 17a and the reaction gas exhaust hole 17 of the other ground electrode 7b, the processing space 11 formed between the surface to be processed 10a of the sample 10 and the electrode unit 9 reacts. A reaction gas flow 18 is formed in the processing space 11 from the reaction gas supply port 16a toward the reaction gas exhaust port 17a.

  Hereinafter, the phase adjustment by the phase delay means 8 will be described. As described above, the phase of the alternating voltage applied to the first application electrode 4 by the first power source 2 is θ1, and the phase of the alternating voltage applied to the third application electrode 5 by the second power source 3 is θ2. Then, the phases θ1 and θ2 are constantly measured by the phase measuring device 14.

  The phase measuring device 14 is connected to the first and second power sources 2 and 3 by the phase adjuster 15, and the phase adjuster 15 has a phase difference Δθ (= θ1−θ2) between the phase θ1 and the phase θ2 as π. The alternating voltage generation operation of the first and second power supplies 2 and 3 is controlled so that (2k + 1) [where k is an integer]. In the present embodiment, the phase adjuster 15 has the first application electrode 4 and the second application electrode 5 with alternating voltages having a phase difference Δθ of π (180 degrees; k = 0) and the same waveform amplitude. And adjust to be applied.

  In the plasma processing apparatus 1 configured as described above, when the voltage + V1 is applied to the first application electrode 4, the voltage −V1 having a phase delayed by π is applied to the second application electrode 5. Thus, a total potential difference of 2V1 is generated between the first application electrode 4 and the second application electrode 5. As a result, a high electric field strength is locally generated between the first application electrode 4 and the second application electrode 5, and is supplied to the processing space 11 between the first application electrode 4 and the second application electrode 5. The atmospheric pressure plasma 19 based on the reaction gas is generated, and the surface to be processed 10 a of the sample 10 is plasma-treated by the active species generated in the atmospheric pressure plasma 19.

  Hereinafter, a specific example in which the electric field strength in the plasma processing apparatus 1 is obtained will be described. FIG. 2 is a diagram showing setting conditions for obtaining the electric field strength, and FIG. 3 is a diagram showing a result of obtaining the electric field strength.

  The first and second application electrodes 4 and 5 are both perfect conductors, the distance between the first application electrode 4 and the second application electrode 5, that is, the thickness of the insulator 6a is 3.0 mm, and the sample 10 of the electrode unit 9 is The distance G between the facing surface and the surface 10a of the sample 10 is set to 4.0 mm. An insulator 6 interposed between the first and second application electrodes 4 and 5 and the ground electrode 7 and covering the first application electrode 4 and the second application electrode 5 is made of alumina having a relative dielectric constant εr = 9.6. And

  An alternating voltage of frequency f = 13.56 MHz is applied to the first application electrode 4 at +0.5 kV, and at the same time, the phase is shifted by π (180 degrees) with respect to the alternating voltage applied to the first application electrode 4 and is large. It is assumed that the same alternating voltage, that is, −0.5 kV is applied at a frequency f = 13.56 MHz. That is, the electric field strength distribution in the vicinity of the sample 10 was calculated when a potential difference of 1.0 kV was applied between the first application electrode 4 and the second application electrode 5.

  In obtaining the electric field strength, the three axes were set to be the same as those in FIG. For the three-dimensional coordinates, the center of the surface of the first application electrode 4 arranged at the center of the three first application electrodes 4 facing the surface to be processed 10a is (X = 0), and the surface to be processed The position obtained by projecting to 10a is (X, Y = 0, 0), and the direction from the surface to be processed 10a to the electrode unit 9 is the positive direction of the Y axis. For the Z axis, an arbitrary cross-sectional position was taken as (Z = 0). The calculation of the electric field intensity is performed by calculating a region A1 immediately below the first application electrode 4, a region B1 immediately below the central portion between the first application electrode 4 and the second application electrode 5, and a region immediately below the second application electrode 5. It performed about the area | region C1 which hits.

  In FIG. 3, the electric field strength distribution in the region A1 is indicated by lines 21a and 21b, the electric field strength distribution in the region B1 is indicated by line 22, and the electric field strength distribution in the region C1 is indicated by lines 23a and 23b. The largest electric field strength of 6.5E5 [V / m] is generated in the hollow portion of the insulator 6a in the region B1 between the first application electrode 4 and the second application electrode 5, and the surface to be processed in the same region B1. In the vicinity of 10a, an electric field strength of 0.02E5 [V / m] is generated. At this time, an electric field strength of 1.0E5 [V / m] is generated in the vicinity of the surface to be processed 10a in the region A1 immediately below the first application electrode 4 and the region C1 immediately below the second application electrode 5.

  As a reference example, the geometric setting is the same as shown in FIG. 2, the voltage is not applied to the second application electrode, the voltage is applied to the first application electrode only at +1.0 kV, and the first application electrode is grounded. The electric field strength distribution was obtained when a potential difference of 1.0 kV was applied between the application electrode and the second application electrode. FIG. 4 is a diagram showing the result of obtaining the electric field strength of the reference case. The electric field intensity calculation position is the same as in the case shown in FIG. 2, and a region A2 immediately below the first application electrode, a region B2 immediately below the central portion between the first application electrode and the second application electrode, 2 It performed about the area | region C2 directly under an application electrode.

  In FIG. 4, the electric field strength distribution in the region A2 is indicated by lines 24a and 24b, the electric field strength distribution in the region B2 is indicated by line 25, and the electric field strength distribution in the region C2 is indicated by line 26. In the case of the reference example, the largest electric field strength of 6.5E5 [V / m] is generated in the recessed portion of the insulator in the region B2 between the first application electrode and the second application electrode. This is the same as the case of 2. However, at this time, only an electric field strength of 0.1 [V / m] is generated in the vicinity of the surface to be processed in the region C2 immediately below the second application electrode, but in the vicinity of the surface to be processed in the region A2 immediately below the first application electrode. Generates an electric field strength of 2.1E5 [V / m].

  In the plasma processing apparatus 1 of the present invention shown in FIGS. 1 to 3, while maintaining the state in which the phase of the alternating voltage applied to the first application electrode 4 and the second application electrode 5 is shifted by π (180 degrees), When the amplitude of the alternating voltage is increased, atmospheric pressure plasma corresponding to the reaction gas is generated in the hollow portion of the insulator 6a in the region B1 where the greatest electric field strength is generated, and depending on the active species generated in the atmospheric pressure plasma. Then, the plasma processing is performed on the processing target surface 10a. In the plasma processing apparatus 1, when the highest electric field strength in the recessed portion of the insulator 6a in the region B1 is Ep1, and the highest electric field strength obtained on the surface to be processed 10a in the region A1 or the region C1 is Es1, the ratio between the two is given. Becomes Ep1 / Es1 = 6.5E5 / 1.0E5 = 6.5 times.

  On the other hand, as in the reference example, the second application electrode is grounded without applying a voltage, a voltage of +1.0 kV is applied only to the first application electrode, and the voltage is between the first application electrode and the second application electrode. When a potential difference of 1.0 kV is applied, the ratio of the highest electric field strength Ep2 in the recessed portion of the insulator 6a in the region B2 to the highest electric field strength Es2 obtained on the surface to be processed in the region C2 is Ep2 / Es2. = 6.5E5 / 2.1E5 = 3.1 times.

  In the case of the reference example, the voltage applied to the first application electrode is increased, and the voltage is 3.1 times the voltage applied when atmospheric pressure plasma is generated between the first application electrode and the second application electrode. Is applied between the first application electrode and the second application electrode, atmospheric pressure plasma is also generated on the surface to be processed of the sample, which means that the surface to be processed of the sample is damaged.

  However, in the plasma processing apparatus 1 of the present invention, the applied voltage to the first application electrode 4 and the second application electrode 5 is increased, and atmospheric pressure plasma is generated between the first application electrode 4 and the second application electrode 5. The atmospheric pressure plasma is not generated on the surface to be processed 10a of the sample 10 until a voltage 6.5 times higher than the voltage applied to the first applied electrode 4 and the second applied electrode 5 is applied. Means. Therefore, in the plasma processing apparatus 1, a larger voltage can be applied to the first and second application electrodes 4 and 5 without generating atmospheric pressure plasma on the surface 10a to be processed. As a result, atmospheric pressure plasma having a high decomposition rate and active species density can be generated with a larger electric field strength, so that plasma processing can be performed at a high processing speed without damaging the surface to be processed 10a. Become.

  FIG. 5 is a diagram showing a simplified configuration of the plasma processing apparatus 31 according to the second embodiment of the present invention. The plasma processing apparatus 31 of the present embodiment is similar to the plasma processing apparatus 1 of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  The plasma processing apparatus 31 includes a single power source 32 and an alternating voltage output from the power source 32, and a second transmission circuit connected to the first transmission circuit 12 and the second application electrode 5 connected to the first application electrode 4. 13, including a voltage branching portion 33 that branches into the first transmission circuit 12, one first dielectric 34 provided in the first transmission circuit 12, and one second dielectric 35 provided in the second transmission circuit 13. Features.

  The voltage branch unit 33 is, for example, a branch terminal, and branches the alternating voltage output from the power source 32 through the power output circuit 36 to the first transmission circuit 12 and the second transmission circuit 13. A first dielectric 34 having a length L11 in the direction of alternating voltage propagation of the first transmission circuit 12 is inserted into the first transmission circuit 12. A second dielectric 35 having a length L21 in the direction of alternating voltage propagation of the third transmission circuit 13 is inserted into the second transmission circuit 13.

  Further, the length of the first transmission circuit 12 that extends in the alternating voltage propagation direction after circuit branching and is not inserted with the first dielectric 34 in the front portion introduced into the electrode unit 9 is L10, Similarly, the length of the second transmission circuit 13 in the portion where the second dielectric 35 in the front portion introduced into the electrode unit 9 is not inserted is L20.

  The alternating voltage of the frequency f oscillated from the power supply 32 is branched and propagated to the first and second transmission circuits 12 and 13 by the voltage branching section 33 and propagates to the first and second application electrodes 4 and 5 of the electrode unit 9. Each is applied. At this time, the phases of the alternating voltages propagating to the first and second transmission circuits 12 and 13 immediately after being branched by the voltage branching unit 33 are equal to each other, and this phase is θ.

Assuming that the phase of the alternating voltage applied to the first application electrode 4 by the first transmission circuit 12 is θ1, the phase θ1 is longer than the phase θ by the length L11 of the first dielectric 34 and the first dielectric 34 The phase is delayed by the length L10 of the portion not inserted. Therefore, when the dielectric constant of the portion of the first transmission circuit 12 where the first dielectric 34 is not inserted is ε10, the magnetic permeability is μ10, the dielectric constant of the first dielectric 34 is ε11, and the magnetic permeability is μ11, the phase is The relationship between θ and phase θ1 is expressed as in equation (1).
θ−θ1 = 2πf {L10 × √ (ε10 · μ10) + L11 × √ (ε11 · μ11)}
... (1)

Assuming that the phase of the alternating voltage applied to the second application electrode 5 by the second transmission circuit 13 is θ2, the phase θ2 has a length L21 of the second dielectric 35 and the second dielectric 35 are compared with the phase θ. The phase is delayed by the length L20 of the portion not inserted. Therefore, when the dielectric constant of the portion of the second transmission circuit 13 where the second dielectric 35 is not inserted is ε20, the magnetic permeability is μ20, the dielectric constant of the second dielectric 35 is ε21, and the magnetic permeability is μ21, the phase is The relationship between θ and phase θ1 is expressed as in equation (2).
θ−θ2 = 2πf {L20 × √ (ε20 · μ20) + L21 × √ (ε21 · μ21)}
... (2)

Therefore, the phase difference Δθ (= θ1−θ2) between the phase θ1 of the alternating voltage applied to the first application electrode 4 and the phase θ2 of the alternating voltage applied to the second application electrode 5 is expressed by the following equation (1). From the formula (2), it is expressed as the following formula (3).
Δθ = 2πf {L20 × √ (ε20 · μ20) + L21 × √ (ε21 · μ21)
−L10 × √ (ε10 · μ10) −L11 × √ (ε11 · μ11)} (3)

In the plasma processing apparatus 31, the lengths L10 and L20 and the dielectric constant ε10 of the first and second transmission circuits 12 and 13 are set so that Δθ given by the expression (3) satisfies the relationship of the expression (4). , Ε20, and magnetic permeability μ10, μ20 are selected and set, and the lengths L11, L21, dielectric constants ε11, ε21, and magnetic permeability μ11, μ21 of the first and second dielectrics 34, 35 are respectively selected and set.
Δθ = π (2k + 1) [where k is an integer] (4)

  Accordingly, the phase difference Δθ between the phase θ1 and the phase θ2 differs by ± π, ± 3π,..., For example, when the voltage V1 is applied to the first application electrode 4, the second application electrode 5 The voltage -V1 is applied to the. Therefore, similarly to the plasma processing apparatus 1 of the first embodiment, a high electric field strength is generated in the hollow portion of the insulator 6a between the first application electrode 4 and the second application electrode 5, and the electric field strength causes decomposition. At the same time as generating a high-pressure atmospheric pressure plasma, a state in which only a low electric field strength is generated can appear in the vicinity of the surface to be processed 10a of the sample 10 immediately below the first and second application electrodes 4 and 5. That is, the plasma processing apparatus 31 is realized that does not damage the surface 10a to be processed of the sample 10 although the plasma processing is possible at a high speed.

  Further, since the alternating voltage oscillated from one power supply 32 is branched by the voltage branching unit 33 and applied to the first and second application electrodes 4 and 5, the alternating voltage is applied to each of the first and second application electrodes 4 and 5. It is not necessary to operate two power supplies for applying the voltage, and interference between the power supplies through the application electrode and the transmission circuit can be prevented.

  The materials of the first and second dielectrics 34 and 35 are not particularly limited, and may be solid, liquid, gas, or vacuum. Furthermore, the dielectric constant ε10 and the magnetic permeability μ10 of the portion of the first transmission circuit 12 where the first dielectric 34 is not inserted may be the same as the dielectric constant ε11 and the magnetic permeability μ11 of the first dielectric 34. . Similarly, the portion of the second transmission circuit 13 where the second dielectric 35 is not inserted has the same dielectric constant ε20 and magnetic permeability μ20, and the dielectric constant ε21 and magnetic permeability μ21 of the second dielectric 35 are the same. Also good.

  FIG. 6 is a diagram showing a simplified configuration of a plasma processing apparatus 41 according to the third embodiment of the present invention. The plasma processing apparatus 41 of the present embodiment is similar to the plasma processing apparatus 31 of the second embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  It should be noted in the plasma processing apparatus 41 that a first dielectric group 42 composed of two dielectrics is inserted into the first transmission circuit 12 and a second dielectric composed of two dielectrics is inserted into the second transmission circuit 13. The group 43 is inserted. The first dielectric group 42 includes an eleventh dielectric 44 and a twelfth dielectric 45. The second dielectric group 43 includes a twenty-first dielectric 46 and a twenty-second dielectric 47.

  In the first transmission circuit 12, the length of the first transmission circuit 12 in the portion where the first dielectric group 42 is not inserted is L10, which is the length in the alternating voltage propagation direction after the voltage branch, and the first dielectric The length of the eleventh dielectric 44 of the body group 42 is L11, and the length of the twelfth dielectric 45 is L12. Further, the (dielectric constant, magnetic permeability) of the first transmission circuit 12, the eleventh dielectric 44, and the twelfth dielectric 45 in the portion where the first dielectric group 42 is not inserted are respectively (ε10, μ10). ), (Ε11, μ11), and (ε12, μ12).

  Similarly, in the second transmission circuit 13, the length of the second transmission circuit 13 in the length in the alternating voltage propagation direction after voltage branching and where the second dielectric group 43 is not inserted is L20, The length of the 21st dielectric 46 of the second dielectric group 43 is L21 and the length of the 22nd dielectric 47 is L22. Further, the (dielectric constant, permeability) of the second transmission circuit 13, the 21st dielectric 46, and the 22nd dielectric 47 of the portion where the second dielectric group 43 is not inserted are respectively (ε20, μ20). ), (Ε21, μ21), (ε22, μ22).

At this time, the phase difference Δθ (= θ1−θ2) between the phase θ1 of the alternating voltage applied to the first application electrode 4 and the phase θ2 of the alternating voltage applied to the second application electrode 5 is expressed by Equation (5). Given in.
Δθ = 2πf {L20 × √ (ε20 · μ20) + L21 × √ (ε21 · μ21)
+ L22 × √ (ε22 · μ22) −L10 × √ (ε10 · μ10)
−L11 × √ (ε11 · μ11) −L12 × √ (ε12 · μ12)} (5)

  In the plasma processing apparatus 41, the lengths L10 and L20 of the first and second transmission circuits 12 and 13 are set so that Δθ given by the equation (5) is π (2k + 1) [where k is an integer]. And dielectric constants ε10, ε20 and magnetic permeability μ10, μ20 are selected and set, respectively, and the lengths L11, L12 of the eleventh and twelfth dielectrics 44, 45 constituting the first dielectric group 42, and the dielectric The ratios ε11 and ε12 and the magnetic permeability μ11 and μ12 are selected and set, and the lengths L21 and L22 of the twenty-first and twenty-second dielectrics 46 and 47 constituting the second dielectric group 43 and the dielectric constant ε21. , Ε22 and magnetic permeability μ21, μ22 are selected and set, respectively. As a result, the plasma processing apparatus 41 can achieve the same effects as the plasma processing apparatus 31 described above.

  The number of dielectrics inserted into the first transmission circuit 12 and the second transmission circuit 13 is not limited to one or two. The first dielectric made of m dielectrics in the first transmission circuit 12 A second dielectric group consisting of n dielectrics can be inserted into the second transmission circuit 13.

  The dielectric constant of the i-th [where i is a positive integer and i ≦ m] dielectric material included in the m [where m is a positive integer] provided in the first transmission circuit is ε1i. The permeability is μ1i, the length in the alternating voltage propagation direction is L1i, the dielectric constant of the portion of the first transmission circuit where the first dielectric group is not provided is ε10, the permeability is μ10, and the length in the alternating voltage propagation direction is This is L10.

  Further, the dielectric constant of the jth [j is a positive integer and j ≦ n] dielectric included in the n [where n is a positive integer] second dielectric group provided in the second transmission circuit. Is ε2j, the permeability is μ2j, the length in the alternating voltage propagation direction is L2j, the dielectric constant of the portion of the second transmission circuit where the second dielectric group is not provided is ε20, the permeability is μ20, and the alternating voltage propagation direction The length of is assumed to be L20.

  At this time, the length, dielectric constant, and magnetic permeability of the first and second transmission circuits 12, 13 and the first and second dielectric groups are selectively set so as to satisfy the following expression (6). The plasma processing apparatus can achieve the same effects as the plasma processing apparatuses 31 and 41 of the second and third embodiments described above.

  When a dielectric group including a plurality of dielectrics is inserted into each of the first and second transmission circuits 12 and 13, the material of each dielectric may be any of solid, liquid, gas, or vacuum The dielectric constant and permeability of each dielectric material may be equal to the dielectric constant and permeability of the first and second transmission circuits 12 and 13.

  FIG. 7 is a diagram showing a simplified configuration of a plasma processing apparatus 51 according to the fourth embodiment of the present invention. The plasma processing apparatus 51 of the present embodiment is similar to the plasma processing apparatus 41 of the third embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  It should be noted in the plasma processing apparatus 51 that the phase θ2 of the alternating voltage applied to the second application electrode 5 is provided in the second transmission circuit 13 to the phase θ1 of the alternating voltage applied to the first application electrode 4. On the other hand, it includes phase delay means 52 that delays by π (2k + 1) [where k is an integer].

  The phase delay means 52 is connected to the first and second transmission circuits 12 and 13 to measure the phase θ1 and the phase θ2, and is provided in the second transmission circuit 13 to measure the phase measurement device 53. And a dielectric adjuster 54 that adjusts the dielectric constant according to the result.

  In this embodiment, the 21st dielectric 46 of the 2nd dielectric group 43 is comprised so that a liquid may be accommodated in a container as a raw material. The dielectric adjuster 54 is connected to the container of the twenty-first dielectric 46 and is configured to allow the liquid as the material of the twenty-first dielectric 46 to be taken in and out of the container. Length L21 and the length L20 of the second transmission circuit 13 where the second dielectric group 43 is not inserted, and the portion where the second dielectric group 43 and the second dielectric group 43 are not inserted The dielectric constant of the second transmission circuit 13 can be adjusted.

  In the plasma processing apparatus 51, the phase measuring unit 53 of the phase delay means 52 constantly measures the phase θ1 and the phase θ2, and the dielectric adjuster 54 is based on the measurement results of the phase θ1 and the phase θ2 as described above. By adjusting the length L21 of the twenty-first dielectric 46 and the length L20 of the second transmission circuit 13, the phase difference Δθ (= θ1-θ2) between the phase θ1 and the phase θ2 is π (2k + 1) [ However, k is controlled to satisfy an integer].

  In this way, the plasma processing apparatus 51 can achieve the same effects as the plasma processing apparatuses 1, 31, and 41 of the present invention described above.

It is a figure which simplifies and shows the structure of the plasma processing apparatus 1 which is 1st Embodiment of this invention. It is a figure which shows the setting conditions which obtain | require an electric field strength. It is a figure which shows the result of having calculated | required the electric field strength. It is a figure which shows the result of having calculated | required the electric field strength of the reference example. It is a figure which simplifies and shows the structure of the plasma processing apparatus 31 which is 2nd Embodiment of this invention. It is a figure which simplifies and shows the structure of the plasma processing apparatus 41 which is 3rd Embodiment of this invention. It is a figure which simplifies and shows the structure of the plasma processing apparatus 51 which is 4th Embodiment of this invention. It is the schematic which shows the structure of the conventional high pressure plasma processing apparatus 100. FIG. It is a figure which shows the calculation position of electric field strength. It is a figure which shows an electric field strength distribution calculation result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 31, 41, 51 Plasma processing apparatus 2, 3, 32 Power supply 4 1st application electrode 5 2nd application electrode 6 Insulator 7 Ground electrode 8, 52 Phase delay means 9 Electrode unit 10 Sample 12 1st transmission circuit 13 1st 2 Transmission circuit 14, 53 Phase measuring device 15 Phase adjuster 33 Voltage branching unit 34, 35, 44, 45, 46, 47 Dielectric 42, 43 Dielectric group 54 Dielectric adjusting device

Claims (3)

A power supply, an application electrode to which an alternating voltage output from the power supply is applied, and a ground electrode provided so as to face and ground the application electrode with an insulator interposed therebetween, the application electrode, the insulator, and the ground An electrode unit composed of an electrode is arranged so as to face the sample, a reactive gas is locally supplied to a space formed by the electrode unit and the sample, and an alternating voltage is applied to the applied electrode. A plasma processing apparatus that generates plasma on a surface facing the sample of the sample and performs processing, film formation, and surface treatment of the sample with the plasma,
The application electrode includes two first application electrodes and a second application electrode,
Applied from the power supply so that the phase difference between the phase of the alternating voltage applied to the first application electrode and the phase of the alternating voltage applied to the second application electrode is π (2k + 1), where k is an integer. A plasma processing apparatus, wherein an alternating voltage is applied to an electrode. A voltage branching section for branching an alternating voltage output from the power source into a first transmission circuit connected to the first application electrode and a second transmission circuit connected to the second application electrode;
The phase of the alternating voltage applied to the second application electrode provided in the second transmission circuit is π (2k + 1) [where k is an integer] with respect to the phase of the alternating voltage applied to the first application electrode. 2. The plasma processing apparatus according to claim 1, further comprising phase delay means for delaying. A voltage branching section for branching an alternating voltage output from the power source into a first transmission circuit connected to the first application electrode and a second transmission circuit connected to the second application electrode;
M [where m is a positive integer] first dielectric group provided in the first transmission circuit;
And n [where n is a positive integer] second dielectric group provided in the second transmission circuit,
The dielectric constant of the i-th dielectric material (where i is a positive integer and i ≦ m) included in the first dielectric group is ε1i, the magnetic permeability is μ1i, and the length in the direction in which the first transmission circuit extends is L1i. ,
The dielectric constant of the portion where the first dielectric group of the first transmission circuit is not provided is ε10, the magnetic permeability is μ10, the length in the direction in which the first transmission circuit extends is L10,
The dielectric constant of the jth [j is a positive integer and j ≦ n] dielectric included in the second dielectric group is ε2j, the magnetic permeability is μ2j, and the length in the direction in which the second transmission circuit extends is L2j. ,
The dielectric constant of the portion where the second dielectric group of the second transmission circuit is not provided is ε20, the magnetic permeability is μ20, and the length in the direction in which the second transmission circuit extends is L20,
Let f be the frequency of the alternating voltage,
When the phase of the alternating voltage applied to the first application electrode is θ1, and the phase of the alternating voltage applied to the second application electrode is θ2,
3. The plasma processing apparatus according to claim 1, wherein an alternating voltage is applied to the first and second application electrodes so that the following expression is satisfied.

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