JP2008198494A - Plasma processing equipment - Google Patents

Abstract

A plasma processing apparatus capable of efficiently performing plasma processing is provided.
A plasma processing apparatus (1) includes an application electrode (2), a pallet (first electrode) (4) having a work (100) and a function as a counter electrode of the application electrode (2), and a plasma processing gas. A gas supply means 11 for supplying, a first circuit (power supply unit) 8 for applying a voltage between the application electrode 2 and the pallet 4, and a lower surface 63 of the table 6 on which the pallet 4 is placed, 9 and has a frequency adjusting means 74 for adjusting the vibration frequency of the vibrator 9 and a control means 70 for controlling the operation of the frequency adjusting means 74. When the surface 110 to be processed of the workpiece 100 is processed while the vibration is integrally vibrated, the control means 70 is configured to operate the frequency adjusting means 74.
[Selection] Figure 1

Description

  The present invention relates to a plasma processing apparatus for plasma processing a workpiece.

2. Description of the Related Art Plasma processing apparatuses that generate plasma, process the surface of a substrate (workpiece), which is an object to be processed (plasma processing), and perform surface modification of the substrate are known.
Such a plasma processing apparatus has a pair of electrodes that are vertically opposed to each other via a substrate, and supplies a predetermined gas to a gap between one electrode of the pair of electrodes and the substrate. However, a voltage is applied between the pair of electrodes to cause discharge, thereby generating plasma. In the generated plasma, electrons accelerated by an electric field collide with gas molecules to generate active species such as excited molecules, radical atoms, positive ions, and negative ions. A part of these active species undergoes various reactions on or near the surface of the substrate, so that the surface of the substrate is modified (for example, see Patent Document 1).

  By the way, in order to efficiently perform plasma processing on the surface of the substrate without depending on changes in the temperature of the atmosphere during the plasma processing, active species involved in surface modification are allowed to stay near the surface of the substrate for a long time. In other words, it is important to contact the substrate surface for a long time. However, the active species generated between the pair of electrodes diffuses between the electrodes and in the chamber, so that it is difficult for the active species to stay locally for a long time near the surface of the substrate. The actual situation is that the improvement of this has not been sufficiently achieved.

Japanese Patent Laid-Open No. 7-85997

  The objective of this invention is providing the plasma processing apparatus which can perform a plasma processing efficiently.

Such an object is achieved by the present invention described below.
The plasma processing apparatus of the present invention includes a first electrode and a second electrode arranged so as to face each other with a workpiece interposed therebetween,
Gas supply means for supplying a gas for generating plasma on the surface to be processed of the workpiece;
A power supply unit that applies a voltage between the first electrode and the second electrode so as to activate the gas supplied by the gas supply means to generate plasma;
A plasma processing apparatus for processing the surface to be processed with plasma generated by the operation of the gas supply means and the power supply unit,
A vibrator that generates a vibration wave in a plasma generation region where the plasma is generated by vibrating at least one of the first electrode, the second electrode, and the workpiece;
Frequency adjusting means for adjusting the frequency of the vibration wave by adjusting the frequency of the vibrator;
Control means for controlling the operation of the frequency adjusting means,
The control means operates the frequency adjustment means to adjust the frequency of the vibration wave.
As a result, the chance of collision between the electron accelerated by the electric field and the constituent material of the gas increases, and the gas activation efficiency is improved. As a result, the plasma processing can be performed efficiently.

In the plasma processing apparatus of the present invention, distance detection means for detecting a distance between the surface to be processed of the workpiece and the surface facing the first electrode or the second electrode facing the surface to be processed;
Moving means for defining a separation distance between the surface to be processed of the workpiece and the facing surface by moving the first electrode or the second electrode;
Prior to processing the surface to be processed of the workpiece, based on the information from the distance detection means, the control means operates the moving means to adjust the separation distance, whereby the separation distance is set. It is preferable that the magnitude is set such that a standing wave is generated between the surface to be processed of the workpiece and the facing surface.
Thereby, a standing wave can be generated between the surface to be processed and the facing surface, and plasma can be unevenly distributed in a region corresponding to a node of the standing wave.

In the plasma processing apparatus of the present invention, it is preferable that the standing wave is generated between the surface to be processed of the workpiece and the facing surface in a direction substantially orthogonal to the surface to be processed of the workpiece.
In the plasma processing apparatus of the present invention, it is preferable that the control means performs control so that the node of the standing wave is positioned on a surface to be processed of the workpiece.
As a result, the active species generated in the plasma receives a force due to the acoustic radiation pressure (standing wave), moves to the vicinity of the surface to be processed of the workpiece, and is captured at this position. Accordingly, the active species stays in the vicinity of the surface to be processed of the workpiece for a long time and reacts sufficiently with the surface to be processed. As a result, good plasma treatment can be efficiently performed on the surface to be processed.

In the plasma processing apparatus of the present invention, it comprises a temperature detection means for detecting a temperature change in a region where the plasma is generated during the processing of the surface to be processed of the workpiece by the plasma,
The control unit prevents the movement of the node of the standing wave from the surface to be processed by operating the frequency adjusting unit based on the temperature change detected by the temperature detecting unit. Is preferred.
As a result, the plasma processing of the surface to be processed is performed more efficiently.

In the plasma processing apparatus of the present invention, comprising a thickness detection means for detecting a change in thickness that occurs during the processing of the surface to be processed of the workpiece by the plasma,
The control means operates the frequency adjusting means based on the change in the thickness detected by the thickness detection means, thereby moving the standing wave node from the surface to be processed of the workpiece. It is preferable to prevent.
As a result, the plasma processing of the surface to be processed is performed more efficiently.

In the plasma processing apparatus of the present invention, a sound pressure detection means for detecting the magnitude of the sound pressure is provided between the surface to be processed of the workpiece and the facing surface,
Preferably, the sound pressure means detects the position of the node of the standing wave between the surface to be processed and the facing surface.
Thereby, the magnitude of the frequency of the vibration wave can be corrected based on the information obtained by the sound pressure detecting means. As a result, the displacement of the node from the surface to be processed is more reliably prevented.

In the plasma processing apparatus of the present invention, it is preferable that the frequency of the standing wave is set within a range of 1 × 10 ⁵ to 1 × 10 ⁸ Hz.
As a result, a larger acoustic radiation pressure can be obtained in the standing wave generated between the surface to be processed and the opposite surface, and this force causes the active species generated in the plasma to move near the surface to be processed. You can stay for a long time.

In the plasma processing apparatus of the present invention, it is preferable to generate a standing wave between the surface to be processed and the facing surface after generating plasma between the surface to be processed and the facing surface.
As a result, plasma is generated prior to the formation of gas density due to standing waves. As a result, active species are continuously supplied to the surface to be processed, and plasma processing of the surface to be processed can be performed more smoothly.

In the plasma processing apparatus of the present invention, the workpiece is placed on the first electrode,
It is preferable that the first electrode and the workpiece are vibrated integrally by the vibrator.
With such a configuration, it is possible to increase the chance of collision between the electron accelerated by the electric field and the constituent material of the gas.
In the plasma processing apparatus of the present invention, the workpiece is placed on the first electrode,
Preferably, the second electrode is vibrated by the vibrator.
With such a configuration, it is possible to increase the chance of collision between the electron accelerated by the electric field and the constituent material of the gas.

In the plasma processing apparatus of the present invention, the gas supply means includes at least one nozzle that is provided through the second electrode and jets the gas between the second electrode and the workpiece. Is preferred.
In the gas supply means having such a configuration, gas is ejected from the second electrode side to the workpiece side by the nozzle, so that active species generated in the plasma ride on this gas flow toward the workpiece side. Flowing. For this reason, there is a concern that the active species may diffuse to the edge side of the workpiece after hitting the surface to be processed. On the other hand, according to the present invention, active species are trapped near the surface of the workpiece, so even if the gas supply means has such a configuration, the active species stays near the surface of the workpiece for a long time. Can be efficiently performed.

Hereinafter, a plasma processing apparatus of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
<First Embodiment>
FIG. 1 is a cross-sectional view (partially including a block diagram) schematically showing a first embodiment of a plasma processing apparatus of the present invention, and FIG. 2 is a diagram showing an application electrode and a workpiece provided in the plasma processing apparatus shown in FIG. FIG. 3 is a block diagram showing a circuit configuration of the plasma processing apparatus shown in FIG. 1, and FIG. 4 is a diagram showing a workpiece covered by the plasma processing apparatus shown in FIG. It is a flowchart of the processing operation with respect to a processing surface. In the following description, the upper side in FIGS. 1 and 2 is referred to as “upper” and the lower side is referred to as “lower”.

  As shown in FIG. 1, the plasma processing apparatus 1 is an apparatus that generates plasma and plasma-processes a processing target (surface) 110 of a workpiece (substrate) 100, for example, a processing target, using the plasma. Application electrode 2 and pallet (first electrode) 4 disposed so as to face each other through workpiece 100, dielectric layer 3 disposed on the surface of application electrode 2 on the side facing workpiece 100, and pallet 4 between the application electrode 2 and the pallet 4, the table 6 that supports 4, the vibrator 9 that is disposed on the surface of the table 6 opposite to the pallet 4 and vibrates by applying a voltage. A first circuit (power supply unit) 8 for applying a voltage, a second circuit 10 for applying a voltage to the vibrator 9, a gas supply means 11 for supplying a gas for generating plasma, a dielectric layer 3, Separation distance from pallet 4 A moving means 5 for defining a, and a distance detecting means 53 for detecting the distance between the dielectric layer 3 and the pallet 4.

Hereinafter, the configuration of each part of the plasma processing apparatus 1 will be described.
The material of the pallet 4 is not particularly limited as long as the pallet 4 can function as an electrode. For example, a simple metal such as copper, aluminum, iron, silver, stainless steel, and the like. Examples include conductive materials having good conductivity, such as various alloys such as steel, brass, and aluminum alloys, intermetallic compounds, and various carbon materials. Moreover, the pallet 4 may be comprised with the laminated body which laminated | stacked two or more layers each comprised from a different electroconductive material.

In the workpiece 100, the processing target surface 110 exposed in the recess 41 is processed by the plasma processing apparatus 1 of the present invention while being accommodated in the recess 41.
The workpiece 100 is not particularly limited. For example, various glasses such as quartz glass and non-alkali glass, various ceramics such as alumina, silica, and titania, various semiconductor materials such as silicon, gallium arsenide, and ITO, and Examples include substrates made of various plastics (resin materials) such as polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, polytetrafluoroethylene, polyimide, liquid crystal polymer, phenol resin, epoxy resin, and acrylic resin. It is done.

Examples of the shape of the workpiece 100 include a plate shape (substrate), a layer shape, and a film shape. As such a workpiece | work 100, the display panel used for a liquid crystal display device, an organic electroluminescent display device, etc., a glass chip, a semiconductor chip, a ceramic chip etc. are mentioned, for example.
Further, the shape of the workpiece 100 (the shape in plan view) is not limited to a rectangular shape, and may be, for example, a circular shape or an elliptical shape.
Although the thickness of the workpiece | work 100 is not specifically limited, Usually, it is preferable that it is about 0.3-1.2 mm, and it is more preferable that it is about 0.5-0.7 mm.

The table 6 supports and fixes the pallet 4.
The table 6 has a concave portion 61 opened on the upper surface thereof, and the pallet 4 is fixed in the horizontal direction in the concave portion 61 and is integrated with the vibration of the table 6 in the vertical direction (by a vibrator 9 described later). It is inserted (inserted) in such a way that it can vibrate in the vibration direction. In this case, the depth of the recess 61 is preferably equal to the thickness of the pallet 4. That is, it is preferable that the upper surface 62 of the table 6 and the upper surface 42 of the pallet 4 inserted into the recess 61 are configured as a flat surface (continuous surface) having substantially no step. Thus, when plasma processing is performed by the plasma processing apparatus 1, the distance between the lower surface of the dielectric layer 3 and the upper surface 62 of the table 6 and the distance between the lower surface of the dielectric layer 3 and the upper surface 42 of the pallet 4 are made equal. Thus, a standing wave to be described later can be reliably generated between them, so that the workpiece 100 can be uniformly and satisfactorily subjected to plasma treatment.

The constituent material of the table 6 is not particularly limited, but various insulating materials are preferably used. For example, various glasses such as quartz glass and alkali-free glass, various ceramics such as silicon dioxide and silicon nitride, polyethylene terephthalate And various plastics (resin materials) such as polyimide.
In the present embodiment, the vibrator 9 is disposed on the lower surface of the table 6 (on the surface opposite to the side on which the pallet 4 is placed) while being connected to the second circuit 10. The configuration of the vibrator 9 and the second circuit 10 will be described in detail later.

The application electrode 2 functions as a counter electrode of the pallet 4 and generates an electric field between the application electrode 2 and the pallet 4 via the workpiece 100 and the dielectric layer 3.
In this embodiment, the application electrode 2 has a substantially rectangular plate shape so that the lower surface (the surface facing the workpiece 100 via the dielectric layer 3) is a flat surface and corresponds to the shape of the pallet 4. The lower surface of the application electrode 2 (the surface facing the workpiece 100) and the surface to be processed 110 of the workpiece 100 are installed so as to be substantially parallel.
In this embodiment, the application electrode 2 and the pallet 4 described above constitute a pair of parallel plate electrodes.

The constituent material of the application electrode 2 is not particularly limited as long as the application electrode 2 can exhibit the function as an electrode, as in the case of the pallet 4. For example, copper, aluminum, iron, Examples thereof include materials having good conductivity such as simple metals such as silver, various alloys such as stainless steel, brass and aluminum alloys, intermetallic compounds, and various carbon materials.
Moreover, the application electrode 2 may be comprised by the laminated body which laminated | stacked two or more layers comprised by the different electroconductive material. Further, the conductive material constituting the application electrode 2 may be the same as or different from the constituent material of the pallet 4.
Note that the planar shape of the application electrode 2 is not limited to the above-described square shape, and may be, for example, a circle, an ellipse, or other irregular shapes. There may be a plurality of application electrodes 2.

The dielectric layer 3 is disposed (bonded) on the lower surface of the application electrode 2 (the surface facing the workpiece 100).
In the present embodiment, the application electrode 2 and the dielectric layer 3 constitute a second electrode, and the lower surface of the dielectric layer 3 forms the facing surface 30 facing the surface 110 to be processed of the workpiece 100. Constitute.
By providing this dielectric layer 3, it is possible to prevent arc discharge from occurring when a voltage is applied between the application electrode 2 and the pallet 4 to generate plasma, and a good (uniform) glow discharge is generated. Can be generated. As a result, good plasma can be generated between the application electrode 2 and the pallet 4.

The constituent material of the dielectric layer 3 is not particularly limited as long as the dielectric layer 3 can function as a dielectric. For example, polytetrafluoroethylene, polyethylene terephthalate, etc. Examples thereof include various plastics (resin material), various glasses such as quartz glass, and inorganic oxides. Examples of the inorganic oxide include metal oxides such as Al ₂ O ₃ , SiO ₂ , ZrO ₂ , and TiO ₂ , and composite oxides such as BaTiO ₃ (barium titanate).

In addition, by using a dielectric having a relative dielectric constant of 10 or more at 25 ° C. as a constituent material of the dielectric layer 3, it is possible to generate a high-density plasma at a low voltage, and the processing efficiency of the plasma processing is further improved. The advantage of improvement is also obtained.
Moreover, the upper limit of the relative dielectric constant of the dielectric layer 3 is not particularly limited, but those having a relative dielectric constant of about 10 to 100 are preferable. The dielectric having a relative dielectric constant of 10 or more corresponds to a metal oxide such as ZrO ₂ or TiO ₂ or a composite oxide such as BaTiO ₃ .

Although the thickness of the dielectric material layer 3 is not specifically limited, It is preferable that it is about 0.01-4.0 mm, and it is more preferable that it is about 1.0-2.0 mm. If the dielectric layer 3 is too thick, a high voltage may be required to generate plasma (desired discharge). If it is too thin, dielectric breakdown occurs during voltage application and arc discharge occurs. There is a fear.
In the present invention, the arrangement of the dielectric layer 3 may be omitted. In this case, the application electrode 2 forms a second electrode, and the lower surface of the application electrode 2 forms an opposing surface that faces the surface 110 to be processed.

The gas supply unit 11 supplies a gas for generating plasma between the application electrode 2 and the workpiece 100.
In the present embodiment, this gas supply means corresponds to the seven nozzles (gas ejection pipes) 16 provided through the application electrode 2 and the dielectric layer 3 (second electrode), and the nozzles 16. A gas supply pipe 12 having a provided branch pipe 121 is connected to the upstream end side of the gas supply pipe 12, filled with a predetermined gas (processing gas + carrier gas), and supplied between the application electrode 2 and the workpiece 100. A gas cylinder (gas supply source) 13 and a regulator (flow rate adjusting means) 14 for adjusting the flow rate of the gas supplied from the gas cylinder 13.

The regulator 14 is disposed downstream of the gas cylinder 13 (on the nozzle 16 side). Further, on the downstream side of the regulator 14 of the gas supply pipe 12, a valve 15 (flow path opening / closing means) 15 that opens and closes the flow path in the gas supply pipe 12 is provided. Controls whether gas is supplied to the side. The gas supply pipe 12 is divided into a plurality of branch pipes 121 on the downstream side of the valve 15, and the downstream ends of the branch pipes 121 are connected to the corresponding nozzles 16.
The number of nozzles 16 is not limited to seven as in the present embodiment, and it is sufficient that at least one nozzle is provided, and the number may be more than seven or less.

  In the gas supply means 11 having such a configuration, when the gas is sent from the gas cylinder 13 with the valve 15 opened, the gas flows in the gas supply pipe 12 and the flow rate is adjusted by the regulator 14. The current is diverted to 121. Thereafter, each nozzle 16 is ejected (supplied) between the application electrode 2 (dielectric layer 3) and the workpiece 100. According to the gas supply means 11 having such a configuration, that is, the gas is supplied between the application electrode 2 and the workpiece 100 by the plurality of nozzles 16 provided penetrating the application electrode 2 and the dielectric layer 3. Thus, the gas can be supplied more uniformly between the application electrode 2 and the workpiece 100. As a result, plasma can be efficiently generated between them, and the plasma treatment for the workpiece 100 can be performed more uniformly and satisfactorily.

The gas supplied between the application electrode 2 and the workpiece 100 is not particularly limited. For example, a processing gas such as O ₂ gas (a gas that mainly contributes to plasma processing) and a carrier gas such as He gas are used. A mixed gas consisting of is preferably used. In the present specification, the “carrier gas” refers to a gas introduced for starting discharge and maintaining discharge.
In the present embodiment, the gas cylinder 13 is filled with a mixed gas (processing gas + carrier gas), but the processing gas and the carrier gas are filled in different gas cylinders, and the gas supply pipe 12 is in the middle. A configuration in which these are mixed at a predetermined mixing ratio may be employed.
Further, the processing gas is not limited to the O ₂ gas as described above as long as it is a gas that generates plasma by applying a voltage (discharge) between the application electrode 2 and the pallet 4. Various gases can be used.

As the other processing gas, for example, the following gas can be used.
For example, in the plasma processing aiming to make the surface 110 of the workpiece 100 water repellent (liquid repellent), CF ₄ , C ₂ F ₆ , C ₃ F ₆ , CClF ₃ , SF _6, etc. are used as processing gases. The fluorine atom-containing compound gas is used.
Further, in the plasma treatment for the purpose of making the surface 110 to be treated hydrophilic (lyophilic), oxygen gas-containing compounds such as O ₃ , H ₂ O, and air, and nitrogen such as N ₂ and NH ₃ are used as treatment gases. Those containing one or both of an atom-containing compound and a sulfur atom-containing compound such as SO ₂ and SO ₃ are used. Thereby, hydrophilic functional groups, such as a carbonyl group, a hydroxyl group, an amino group, are formed in the to-be-processed surface 110 of the workpiece | work 100, surface energy can be made high and a hydrophilic surface can be obtained. Alternatively, a hydrophilic polymer film can be deposited (formed) using a polymerizable monomer having a hydrophilic group such as acrylic acid or methacrylic acid.

Further, in the plasma treatment for the purpose of adding an electrical and optical function to the surface 110 to be processed of the workpiece 100, a metal oxide thin film such as SiO ₂ , TiO ₂ , SnO ₂ or the like is used as the surface 110 to be processed of the workpiece 100. In order to form a film, a material containing a metal metal-hydrogen compound such as Si, Ti, or Sn, a metal-halogen compound, a metal alkoxide (organometallic compound), or the like is used.

Further, for example, a halogen-based gas is used in plasma processing for the purpose of etching processing or dicing processing, and for example, oxygen-based gas is used for plasma processing for the purpose of resist processing or removal of organic contamination. In plasma processing for the purpose of surface cleaning and surface modification, for example, an inert gas such as Ar or N ₂ is used as a processing gas, and surface cleaning or surface modification is performed with plasma of the inert gas.
Further, the carrier gas is not limited to He gas. In addition, for example, a rare gas such as Ne, Ar, or Xe, N ₂ gas, or the like can be used, and these may be used alone or in combination of two or more. But it can also be used.

Note that the ratio (mixing ratio) of the processing gas in the mixed gas varies depending on the type of plasma processing, but if the processing gas ratio is too large, it is difficult to generate plasma (discharge) or the efficiency of the plasma processing. For example, the ratio of the processing gas in the mixed gas is preferably about 1 to 10%, more preferably about 5 to 10%.
The flow rate of the gas to be supplied is appropriately determined according to the type of gas, the purpose of the plasma treatment, the degree of treatment, etc., and is not particularly limited, but it is usually preferably about 30 SCCM to 3 SLM.

  Here, a predetermined gas is supplied between the dielectric layer 3 and the workpiece 100 (gap) using the gas supply means 11, and a predetermined voltage, for example, a high frequency is applied between the application electrode 2 and the pallet 4. When a voltage (voltage) is applied, an electric field is generated between the application electrode 2 and the pallet 4, that is, between the dielectric layer 3 and the workpiece 100, so that discharge, that is, glow discharge (barrier discharge). Occurs. By this discharge, the supplied gas is activated (ionization, ionization, excitation, etc.), and plasma is generated. And the to-be-processed surface 110 of the workpiece | work 100 is processed (plasma process) by the active species 20, such as the excited molecule, radical atom, positive ion, and negative ion which arose in this plasma.

The moving means 5 defines a separation distance between the dielectric layer 3 and the pallet 4, that is, a separation distance between the facing surface 30 and the surface to be processed 110.
Examples of the moving means 5 include those using a cylinder such as an air cylinder or a hydraulic cylinder, and those using an actuator such as a motor and a piezoelectric element. In this embodiment, FIG. 1 and FIG. As shown in FIG. 4, a cylinder 50 is used as the moving means 5.

In this embodiment, the table 6 is supported via two cylinders 50 that operate in conjunction with each other.
The cylinder 50 includes a cylinder body 51 and a piston 52 that is positioned on the upper end side of the cylinder 50 and can be expanded and contracted with respect to the cylinder body 51. The cylinder body 51 is grounded and fixed at the lower end side, and the piston 52 is fixed to the table 6 at the upper end side. By setting it as this structure, the cylinder 50 can adjust the length by extending / contracting the piston 52 by hydraulic pressure or air pressure, respectively.
Therefore, the to-be-processed surface 110 can be moved with respect to the opposing surface 30 by extending and contracting the two cylinders 50 having such a configuration. Thereby, the separation distance between the processing target surface 110 and the facing surface 30 can be adjusted (defined) to a desired size.

A distance detecting means 53 is provided on the upper surface 42 side of the pallet 4.
The distance detection unit 53 has a function of detecting a separation distance between the processing target surface 110 and the facing surface 30.
In this embodiment, the distance detection unit 53 is provided such that the detection unit (not shown) of the distance detection unit 53, the upper surface 42 of the pallet 4, and the processing target surface 110 of the workpiece 100 form a flat surface. It has been. With such a configuration, the separation distance between the processing target surface 110 and the facing surface 30 can be reliably measured.

Such a distance detection means 53 is constituted by, for example, a laser displacement meter that detects the separation distance between the processing surface 110 and the facing surface 30 by irradiating the facing surface 30 with laser light and measuring the reflected light. can do. According to the distance detecting means constituted by the laser displacement meter, the separation distance between the surface to be processed 110 and the facing surface 30 can be detected relatively easily and reliably.
Such a cylinder 50 and the distance detection means 53 are each connected to the control means 70 mentioned later, as shown in FIG. Such a control means 70 operates the cylinder 50 on the basis of the measurement value (information) detected by the distance detection means 53, and thereby the desired separation distance between the processing target surface 110 and the facing surface 30 is obtained. The interval can be set.

The distance between the dielectric layer 3 and the workpiece 100 (the distance between the facing surface 30 and the surface to be processed 110) includes the output of a high-frequency power source 82 described later, the type of plasma treatment applied to the workpiece 100, the thickness of the workpiece 100, and the like. However, it is usually preferably set to about 0.3 to 2 mm, more preferably about 0.3 to 1 mm. Thereby, a necessary and sufficient electric field can be generated between the dielectric layer 3 and the workpiece 100.
Note that the distance between the dielectric layer 3 and the workpiece 100 is one of the important conditions for performing a uniform and appropriate plasma treatment on the surface to be processed 110 (including the type of gas, the flow rate, the applied voltage, etc.). In addition, this is an important condition for generating a standing wave described later between the dielectric layer 3 and the workpiece 100.

  Further, in the present embodiment, a high frequency power source (power source unit) 82 is connected to the application electrode 2 via a conducting wire (cable) 81 as shown in FIG. Matcher) 84 is provided. The pallet 4 is connected to a high-frequency power source 82 through a conductive wire 81, a matching box 84 for impedance matching, and a switch 83 for switching between a conductive state and a non-conductive state. The conductive wire 81, the high frequency power supply 82, the switch 83, and the matching box 84 constitute a first circuit (power supply unit) 8 for applying a voltage (high frequency voltage) between the application electrode 2 and the pallet 4. Yes. A part of the first circuit 8, that is, the conductive wire 81 on the pallet 4 side is grounded.

When the switch 83 is closed, the pallet 4 is grounded through conduction of the conductive wire 81, whereby a high frequency voltage (voltage) can be applied between the pallet 4 and the application electrode 2, and when the switch 83 is opened. The conducting wire 81 is in a non-conducting state (cut-off state), no voltage is applied between the pallet 4 and the applying electrode 2, and no plasma is generated.
Although not shown, the first circuit 8 may include a power frequency adjusting means (circuit) for changing the frequency of the high frequency power supply 82 and a power (power) adjusting means for the high frequency power supply 82. Thereby, the processing conditions of the plasma processing with respect to the workpiece | work 100 can be adjusted as needed.

When plasma processing is performed on the workpiece 100, the high frequency power supply 82 is activated, the switch 83 is closed, and a voltage is applied between the pallet 4 and the application electrode 2. At this time, an electric field is generated between the pallet 4 and the application electrode 2, and when gas is supplied from the gas supply means 11, discharge is generated and plasma is generated by activating this gas. .
In addition, since the impedance matching is performed when the first circuit 8 includes the matching box 84 as in the present embodiment, the strength of the electric field generated between the pallet 4 and the application electrode 2 is increased. Is kept constant. As a result, the density of the plasma generated between them is also kept constant.
The frequency of the high-frequency power source 82 is not particularly limited, but is preferably about 10 to 50 MHz, and more preferably about 10 to 40 MHz.

  By the way, the present inventor is caused by the above problem, that is, the active species 20 generated in the plasma cannot stay in the vicinity of the surface (surface) 110 of the workpiece (substrate) 100 for a long time. Thus, in view of the fact that the processing efficiency of the plasma processing is not sufficiently improved, as a result of intensive studies, the surface to be processed 110 is processed by plasma while the pallet 4 and the workpiece 100 are vibrated integrally by the vibrator 9. It was found that the above problems can be solved by processing the above. In particular, the vibrator 9 generates a standing wave between the surface to be processed 110 and the facing surface 30, and the node of the standing wave is positioned on the surface to be processed 110. Has been found to be improved.

Hereinafter, the vibrator 9 will be described in detail.
The vibrator 9 is disposed on the lower surface 63 of the table 6, that is, on the lower side of the pallet 4 through the table 6 while being connected to the second circuit 10.
The vibrator 9 vibrates when power is supplied from the second circuit 10 to vibrate the application electrode 2 and the workpiece 100 integrally, and a vibration wave is generated between the surface to be processed 110 and the facing surface 30. (Sound wave) is generated.
In this embodiment, the vibrator 9 includes a pair of electrodes 92 and 93 and a piezoelectric body 91 provided between the pair of electrodes 92 and 93 so as to be in contact with both of them. An electrode 92 that is an upper electrode is joined to the lower surface 63 of the table 6.

The piezoelectric body 91 is made of a piezoelectric material and is formed in a plate shape. With such a configuration, when a voltage is applied between the pair of electrodes 92 and 93, the function as a deformable diaphragm can be reliably exhibited.
The piezoelectric material is not particularly limited, and for example, quartz (SiO ₂ ), barium titanate (BaTiO), lead titanate (PbTiO ₃ ), lead zirconate titanate (Pb (Zr, Ti) O ₃ ), Lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O ₃ ), lithium niobate (LiNbO ₃ ), lead metaniobate (PbNb ₂ O ₆ ), PZT (solid solution of lead zirconate and lead titanate) ), Piezoelectric polymer films such as polyvinylidene fluoride (PVDF), and zinc oxide (ZnO). By configuring the piezoelectric body 91 with such a piezoelectric substance, the piezoelectric body 91 can be suitably deformed when a voltage is applied between the pair of electrodes 92 and 93, and the piezoelectric body 91 can be used as a vibration plate. The function of can be demonstrated reliably.

In the present embodiment, the piezoelectric body 91 has a substantially rectangular plate shape. The shape (shape in plan view) of the piezoelectric body 91 is not limited to a rectangular shape, and may be, for example, a circular shape or an elliptical shape.
The thickness of the piezoelectric body 91 is not particularly limited, but is preferably about 0.01 to 4.0 mm, and more preferably about 0.1 to 2.0 mm.

In addition, the pair of electrodes 92 and 93 can have the same configuration as the application electrode 2 described above.
One electrode 92 of the pair of electrodes is connected to the AC power source 102 via frequency adjusting means (regulator) 74 that adjusts the frequency of the conductor (cable) 101 and the high frequency power source 102, that is, the frequency of the vibrator 9. The other electrode 93 is connected to the AC power source 102 via the conductive wire 101 and the switch 103 that switches between the conductive state and the non-conductive state, whereby the second electrode 93 for applying an AC voltage to the vibrator 9 is connected. A circuit 10 is configured.
When the switch 103 is closed, the conducting wire 101 becomes conductive, and an AC voltage can be applied between the electrodes 92 and 93. When the switch 103 is opened, the conducting wire 101 becomes non-conductive (cut-off state), and the electrodes 92 and 93 No voltage is applied between them.

  When the vibrator 9 is vibrated, the AC power source 102 and the frequency adjusting unit 74 are operated, the switch 103 is closed, and an AC voltage is applied to the piezoelectric body 91. At this time, the piezoelectric body 91 expands and contracts (deforms) up and down at a predetermined frequency by the piezoelectric effect, and by following the deformation, the electrode 92, the table 6, the pallet 4, and the workpiece 100 disposed on the upper side thereof. Vibrates up and down. Thus, when a gas is supplied between the workpiece 100 and the dielectric layer 3 in a state where the pallet 4 and the workpiece 100 vibrate integrally, the space between the dielectric layer 3 and the workpiece 100 also vibrates. Therefore, the chance of collision between the electron accelerated by the electric field and the constituent material of the gas increases, and the activation efficiency of the gas is improved. As a result, the plasma processing of the processing target surface 110 can be performed efficiently.

Then, by adjusting the frequency of the high-frequency power source 102 by the frequency adjusting means 74, that is, by adjusting the frequency of the vibrator 9, a periodic roughness (sound wave) is formed in the space between the dielectric layer 3 and the workpiece 100. ) Can be generated at a desired frequency. This sound wave (traveling wave) travels in a direction substantially perpendicular to the surface 110 to be processed and is reflected by the opposing surface 30 to generate a reflected wave. The reflected wave and the traveling wave overlap, A standing wave W substantially perpendicular to the surface to be processed 110 as shown in FIG. 2 is generated between the processing surface 110 and the facing surface 30.
Here, in the standing wave W, sound pressure nodes W _{1 and} antinodes W ₂ are alternately present at intervals of ¼ wavelength with respect to the propagation direction of the sound wave, and the position of the node W ₁ is a change in density. It is a stable place with little or no change in density.

In general, when a minute object that is sufficiently smaller than the wavelength of a sound wave is introduced into the sound field of such a standing wave W, the object moves from the sound pressure antinode W ₂ toward the node W ₁ (acoustic radiation pressure). subjected to a force) according to a phenomenon that is observed is known that is trapped in position (region) corresponding to a node W ₁ of the sound pressure. Therefore, when plasma is generated between the processing target surface 110 where such a standing wave is generated and the facing surface 30, the plasma (active species 20) can be unevenly distributed in a region corresponding to the node W _1. It becomes like this.

On the other hand, a constant that is an integer multiple of the wavelength of the standing wave is n, the frequency of the sound wave is f [Hz], the speed of the sound wave (in the air, 273 K, 1 atm) is C ₀ [m / sec], and faces the surface 110 to be processed. When the separation distance (gap) from the surface 30 is L [mm] and the gas temperature (that is, the temperature in the region where the plasma is generated) is T [K], the period n satisfies the relationship of the following formula 1. Therefore, the positions of the nodes W _{1 and the} antinodes W ₂ of the standing wave W are changed by appropriately setting at least one parameter among the frequency f, the separation distance L, and the gas temperature T, for example. That is, by setting the parameters appropriately, it is possible to move the positions of the nodes W ₁ and ventral W ₂ at an arbitrary position.
f = nC ₀ / 2L · √ (T / 273) · 10 ³ (1)

Therefore, in a state in which plasma is generated between the workpiece 100 and the electrode 2, so that the position of the section W ₁ of the workpiece 100 side, coincides with the treatment surface 110 of the workpiece 100, the frequency f, the distance L And at least one parameter of the gas temperature T is set to generate the standing wave W. As a result, the active species 20 generated in the plasma receives a force due to the acoustic radiation pressure (standing wave) and moves to the vicinity of the surface 110 to be processed of the workpiece 100 (position of the node W ₁ of the standing wave W). Captured at this position. Therefore, the active species 20 stays in the vicinity of the surface 110 to be processed of the workpiece 100 for a long time and reacts sufficiently with the surface 110 to be processed. As a result, it is possible to efficiently perform a good plasma process on the surface 110 to be processed.

The separation distance between the surface to be processed 110 and the facing surface 30 is set to a size that can generate a necessary and sufficient electric field between the dielectric layer 3 and the workpiece 100 as described above. from, depending on the magnitude of the separation distance, in order to position the section W ₁ to the processing surface 110, preferably configured to set the size of the frequency f as appropriate. With such a configuration, the node W ₁ can be positioned on the processing surface 110 relatively easily and reliably.
The frequency f can be set (adjusted) by controlling the operation of the frequency adjusting means 74 by the control means 70 described later.

The frequency of the standing wave W generated between the workpiece 100 and the application electrode 2 is preferably set between about 1 × 10 ⁵ to 1 × 10 ⁸ Hz, and about 1 × 10 ^{5 to} 5 × 10 ⁷ Hz. It is more preferable to set between.
In the present embodiment, the vibrator 9 is provided so as to overlap almost the entire workpiece 100. With this configuration, the active species 20 can be uniformly captured by the force of the acoustic radiation pressure as described above over the entire surface to be processed 110 of the workpiece 100, so that the plasma processing of the surface to be processed 110 can be performed uniformly and efficiently. It can be performed.

The operation for generating the standing wave W is preferably performed after the operation for generating plasma between the workpiece 100 and the application electrode 2. By generating the standing wave W after the plasma is generated, the plasma is generated before the air density due to the standing wave W is formed. As a result, the active species 20 is continuously supplied to the surface 110 to be processed, and the plasma processing of the surface 110 to be processed can be performed more smoothly.
Although not shown, the second circuit 10 may include a power adjustment unit for the AC power source 102. Thereby, the generation conditions of the standing wave W can be adjusted as needed.

  Further, in this embodiment, the vibrator 9 is disposed on the lower surface 63 of the table 6, but may be disposed on the upper surface 42 of the pallet 4, and may be disposed on both the lower surface 63 and the upper surface 42. You may make it do. However, if the vibrator 9 is disposed on the upper surface 42 of the pallet 4, the surface of the vibrator 9 may be exposed to the active species 20, and it is difficult to maintain the vibration characteristics. Therefore, it is preferable to arrange the vibrator 9 on the lower surface of the pallet 4 as in this embodiment.

By the way, as shown in the above formula 1, the frequency f of the sound wave (vibration wave) is the temperature T in the region where the plasma is generated (hereinafter sometimes simply referred to as “plasma generation region”), and the processing target. It depends on the distance L between the surface 110 and the facing surface 30. The magnitudes of the temperature T and the separation distance L change as the plasma processing of the surface 110 to be processed proceeds. That is, the temperature T tends to increase as the plasma processing of the surface 110 to be processed progresses, and the separation distance L varies depending on the type of plasma processing described above, but is large in the case of etching processing or dicing processing, for example. In the case of plasma treatment for the purpose of adding a hydrophilic treatment, a liquid repellency treatment, and an electrical or optical function, it becomes small.
Therefore, in order to efficiently plasma treatment of the treated surface 110, the section W ₁ of the standing wave W, until the completion of the plasma treatment started, that is positioned to be processed surface 110 preferably. In other words, it is preferable to change (adjust) the frequency f of the sound wave as the plasma processing proceeds.

As described above, the plasma processing apparatus 1 of the present embodiment has been described above as shown in FIGS. 1 to 3 so that the frequency f can be changed according to changes in the temperature T and the separation distance L. By adjusting the frequency of the vibrator 9, a frequency adjusting means 74 for adjusting the frequency of the vibration wave, a temperature detecting means 71 for detecting a temperature change in a region where the plasma is generated, and a surface 110 to be processed by the plasma. Thickness detecting means 72 for detecting a change in thickness that occurs during the process, and control means 70 for controlling the operation of the frequency adjusting means 74. Further, the plasma processing apparatus 1 includes a sound pressure detecting means 73 for measuring the positions of the nodes W ₁ and the antinodes W ₂ of the standing wave W and an operation unit 75 for inputting an instruction such as start of the plasma processing. Is provided.

In this embodiment, the temperature detection means 71 is provided on the facing surface 30 side of the dielectric layer 3. With this configuration, the temperature in the region between the surface to be processed 110 and the facing surface 30, that is, the temperature in the plasma generation region can be reliably measured, and the temperature in the plasma generation region generated during processing of the surface to be processed 110. A change can be reliably detected.
Such a temperature detection means 71 can be comprised with a thermocouple, a platinum resistance temperature detector, a thermistor, an infrared thermography, etc., for example. For example, according to the temperature detection means constituted by a thermocouple, a temperature change in the plasma generation region can be detected relatively easily with a simple configuration.

  Further, the thickness detecting means 72 is provided so as to be connected to the matching box 84. This thickness detection means 72 is used to record changes in the current, voltage, phase difference, etc. that occur because the matching box 84 matches the magnitude of the impedance so that the plasma density in the plasma generation region is constant. Based on this, a change in thickness that occurs during processing of the processing surface 110 is indirectly detected. By providing such a thickness detection means 72, it is possible to detect a change in the thickness of the processing target surface 110, so that the change in the distance L between the processing target surface 110 and the facing surface 30 can be reliably detected. Can be detected. Note that the relationship between the history of changes in current, voltage, phase difference, and the like, and the change in thickness that occurs during processing of the processing target surface 110 can be experimentally determined in advance.

Further, the sound pressure detecting means 73 is between the surface to be processed 110 and the opposing surface 30 of the workpiece 100 with respect to the X direction shown in FIG. 1 (a direction substantially perpendicular to the longitudinal direction of the surface to be processed 110). It is provided so that it can move. By positioning such a sound pressure detecting means 73 in the vicinity of the surface 110 to be processed, the sound pressure on the surface 110 to be processed can be measured. Whether or not ₁ is located can be reliably detected.
Such a sound pressure detecting means 73 can be constituted by, for example, a sound pressure gauge that includes a piezoelectric element as a sensor and converts vibration of the piezoelectric element into an electric signal.

The control unit 70 is connected to the frequency adjusting unit 74 and controls the operation of the vibrator 9 by operating the frequency adjusting unit 74.
The control means 70 is connected to a temperature detection means 71, a thickness detection means 72, a sound pressure detection means 73, a distance detection means 53, and the like, and these measurement results (detection results) are inputted as needed.
The control means 70 includes, for example, a microcomputer (CPU), a temperature detection means 71, a thickness detection means 72, a sound pressure detection means 73, a memory that temporarily records (stores) measurement values of the distance detection means 53, and It is composed of a time clock for generating a time signal indicating time.

Such a control means 70 operates the vibrator 9 by operating the frequency adjusting means 74 based on the measured value (output signal) measured at least one of the temperature detecting means 71 and the thickness detecting means 72. The frequency f of the sound wave (vibration wave) generated when the vibrator 9 vibrates can be changed.
As described above, since the frequency f can be changed by the control means 70, even if the temperature T and the size of the separation distance L change as the plasma processing of the processing target surface 110 proceeds, the standing wave is changed. W positions of the nodes W ₁ of can be reliably prevented from moving from the treatment surface 110. As a result, the plasma processing of the processing target surface 110 is performed more efficiently.

At this time, in this embodiment, the sound pressure detecting means 73 can detect the position of the node W ₁ of the standing wave W between the processing target surface 110 and the facing surface 30. Thus, based on the information obtained by the sound pressure detecting means 73, since it can be confirmed whether the section W ₁ of the standing wave W is positioned surface to be processed 110, corrects the magnitude of the frequency f can do. As a result, positional deviation of the node W ₁ from the processing surface 110 due to the magnitude of the temperature T and the distance L is changed can be more reliably prevented.

The control means 70 may be configured to operate the frequency adjustment means 74 based on the measurement value measured by either the temperature detection means 71 or the thickness detection means 72. However, the temperature detection means 71 It is preferable that the frequency adjusting means 74 is operated based on the measured value measured by both the thickness detecting means 72 and the thickness detecting means 72. During the processing of the processing surface 110, the positions of the nodes W ₁ of the standing wave W can be more reliably prevented from moving from the treatment surface 110. As a result, the plasma processing of the processing target surface 110 is performed more efficiently.

  As the operation unit 75, for example, a touch panel including a keyboard, a liquid crystal display panel, an EL display panel, or the like can be used. In this case, the operation unit 75 displays display means (notification) for displaying (notifying) various types of information. (Means) may also be used. Information input from the operation unit 75 includes, for example, the type of processing gas used for plasma processing, the supply amount of processing gas, the operating conditions of the first circuit 8, the separation distance between the processing target surface 110 and the facing surface 30, and the workpiece. Information (thickness, width, etc.).

Next, the operation (operation) of the above-described plasma processing apparatus 1 of the present invention will be described based on the flowchart shown in FIG. In the figure, S indicates each step of the flow.
[1] First, after placing the surface to be processed 110 of the workpiece 100 on the pallet 4 (first electrode), the moving surface 5 is operated, whereby the surface to be processed 110 and the facing surface 30 are moved. Is set to a predetermined size (step S1).
The separation distance L is moved based on the measurement value (information) detected by the distance detection unit 53 until the control unit 70 reaches a target size (a size input by the operator to the operation unit 75). Set by activating means 5.

[2] Next, by the operation of the first circuit 8, the high-frequency power source 82 is operated and the switch 83 is closed. Further, the valve 15 is opened by the operation of the gas supply means 11, and the gas is sent from the gas cylinder 13 while adjusting the flow rate of the gas with the regulator 14.
As a result, the gas delivered from the gas cylinder 13 flows through the gas supply pipe 12, is divided into each branch pipe 121, and is ejected (supplied) between the dielectric layer 3 and the workpiece 100 from each nozzle 16. On the other hand, by the operation of the high frequency power source 82, a high frequency voltage is applied between the application electrode 2 and the pallet 4, and an electric field is generated between them.

Here, the gas flowing between the application electrode 2 and the workpiece 100 is activated by discharge between the portion where the electric field is generated, that is, between the surface to be processed 110 and the opposing surface 30, and plasma is generated. To do. Thereby, the plasma processing is performed on the processing target surface 110 of the workpiece 100 (step S2).
At this time, the AC power source 102 and the frequency adjusting means 74 are operated, and the switch 103 is closed. The frequency adjusting means 74 is a frequency f calculated based on the temperature T of the plasma generation region detected by the temperature detecting means 71 and the distance detecting means 53, respectively, and the magnitude of the separation distance L set in step S1. Is controlled by the control means 70 so that the vibrator 9 vibrates at a predetermined frequency.

As a result, the vibrator 9 vibrates at a predetermined frequency, and a standing wave W in which the position of the node W ₁ is located on the processing surface 110 is generated between the processing surface 110 and the facing surface 30. As a result, the active species 20 generated in the plasma receives a force due to the acoustic radiation pressure (standing wave) and moves to the vicinity of the surface 110 to be processed of the workpiece 100 (position of the node W ₁ of the standing wave W). Captured at this position. Therefore, the active species 20 stays in the vicinity of the surface 110 to be processed of the workpiece 100 for a long time and reacts sufficiently with the surface 110 to be processed. As a result, good plasma processing is efficiently performed on the surface 110 to be processed.

[3] Next, it is determined whether or not the temperature T and the separation distance L are changed by the progress of the plasma processing on the processing target surface 110 (step S3).
If no change is found in both the temperature T and the separation distance L in step S3 (“NO” in step S3), the process returns to step S2 to continue the plasma processing of the processing target surface 110.

On the other hand, in step S3, if a change to at least one of the temperature T and the distance L are observed ( "YES" in step S3), the section W ₁ of the standing wave W is not moved from the treatment surface 110 As described above, by operating the frequency adjusting means 74, the frequency f of the sound wave is changed (step S4). Thus, the section W ₁ of the standing wave W in a state that does not move from the surface to be processed 110, to continue the plasma treatment of the surface to be processed 110 (step S5).

[4] Next, it is determined whether or not the separation distance L has changed to a target size as the processing of the processing target surface 110 with plasma proceeds (step S6).
In step S6, when the separation distance L has not changed to the target size (“NO” in step S6), the process returns to step S2 to continue the plasma processing of the processing target surface 110.

On the other hand, when the separation distance L has changed to the target size in step S6 (“YES” in step S6), the plasma processing is terminated and the present flow is terminated.
In the gas supply means 11 having the configuration as described in the present embodiment, since the gas is ejected from the application electrode 2 side to the workpiece 100 side by the nozzle 16, the active species 20 generated in the plasma It rides on the gas flow and flows toward the work 100 side. For this reason, there is a concern that the active species 20 may diffuse to the edge side of the table 6 (workpiece 100) after hitting the surface 110 to be processed.

However, in this embodiment, the vibrator 9 is disposed on the lower surface 63 of the table 6, and the node W ₁ on the workpiece 100 side is positioned between the surface to be processed 110 and the facing surface 30. Since the standing wave W is configured to be generated, the active species 20 is captured in the vicinity of the surface 110 to be processed. Therefore, the active species 20 stays in the vicinity of the surface to be processed 110 of the workpiece 100 for a long time, and good plasma processing can be efficiently performed on the surface to be processed 110 of the workpiece 100.
That is, the present invention is particularly effective when applied to the gas supply means 11 having such a configuration.

In the present embodiment, the temperature detection means 71 and the thickness detection means 72 detect the temperature change T in the plasma generation region and the change in the thickness of the processing surface 110, that is, the separation distance L, respectively, and the degree of these changes. Accordingly, the frequency f of the vibrator 9 is adjusted by the frequency adjusting unit 74 in accordance with the frequency f of the sound wave, and the node W _{1 of the} standing wave W is positioned on the processing surface 110. is not limited to such a case, belly W ₂ may be configured such that the position to be processed surface 110. By adopting such a configuration, it is possible to perform the processing of the processing target surface 110 at a relatively slow speed, so that it is possible to easily control the plasma processing.

Second Embodiment
FIG. 5 is a cross-sectional view (including a partial block diagram) schematically showing a second embodiment of the plasma processing apparatus of the present invention. Hereinafter, the second embodiment shown in FIG. 5 will be described, but the description will focus on the points different from the first embodiment, and the description of the same matters will be omitted.
The second embodiment shown in FIG. 5 is the same as the first embodiment except for the configuration of the gas supply means 11. That is, the gas supply means 11 does not have the nozzle 16 and the branch pipe 121, and the gas supply pipe 12 is installed so that the downstream end side thereof is located between the application electrode 2 and the workpiece 100.

In the gas supply means 11 having such a configuration, a predetermined gas is sent out from the gas cylinder 13 with the valve 15 opened, and this gas flows through the gas supply pipe 12 and the flow rate is adjusted by the regulator 14. Thereafter, the gas is introduced (supplied) between the application electrode 2 (dielectric layer 3) and the workpiece 100 from a gas outlet formed at the downstream end of the gas supply pipe 12.
Also in the second embodiment, the same operation and effect as the first embodiment can be obtained.

<Third Embodiment>
FIG. 6 is a cross-sectional view (including a partial block diagram) schematically showing a third embodiment of the plasma processing apparatus of the present invention. Hereinafter, the third embodiment shown in FIG. 6 will be described, but the description will focus on the points different from the first embodiment, and the description of the same matters will be omitted.
The third embodiment shown in FIG. 6 differs in the configuration of the application electrode 2 and the nozzle 16 except that the vibrator 9 is provided on the application electrode 2 side instead of being provided on the workpiece 100 side. The main configuration is substantially the same as that of the first embodiment.

In the plasma processing apparatus 1 of the present embodiment, as shown in FIG. 6, the lower surface 22 of the application electrode 2 is smaller than the surface to be processed 110, and the nozzle 16 includes the application electrode 2 and a dielectric. One is formed so as to penetrate the layer 3, and the vibrator 9 is formed so as to cover a part of the outer peripheral surface of the application electrode 2 via an insulator 94.
The distance detecting means 53 is provided on the facing surface 30 side of the dielectric layer 3 instead of being provided on the upper surface 42 side of the pallet 4. Thereby, even when the lower surface 22 of the application electrode 2 is smaller than the surface to be processed 110 as in the present embodiment, the separation distance between the surface to be processed 110 and the facing surface 30 is ensured. Can be detected.
In the plasma processing apparatus 1 having such a configuration, when the application electrode 2 or the workpiece 100 is scanned, the processing target 110 of the workpiece 100 is subjected to plasma processing while changing the positional relationship with each other.

Further, when scanning the application electrode 2 or the workpiece 100, the position of the sound pressure detecting means 73 is changed so as to be positioned between the application electrode 2 and the workpiece 100 as shown in FIG.
Also in the third embodiment, the same operation and effect as in the first embodiment can be obtained.
In the plasma processing apparatus 1 according to the present embodiment, the plasma generation region is smaller than that in the first embodiment. Therefore, since the region where the standing wave is generated is also reduced, the standing wave can be generated relatively easily and stably between the surface to be processed 110 and the facing surface 30 by the vibrator 9.

As described above, the plasma processing apparatus of the present invention has been described based on the illustrated embodiments. However, the present invention is not limited to these embodiments, and the configuration of each unit is an arbitrary configuration having the same function. Can be replaced. Moreover, other arbitrary structures and processes may be added.
Further, the present invention may be a combination of any two or more configurations (features) of the above embodiments.

In the first and second embodiments, the positional relationship between the pallet 4 and the application electrode 2 with respect to the longitudinal direction of the pallet 4 is fixed, but at least one of the table 6 and the application electrode 2 is used. Further, a moving means that is movable in the longitudinal direction of the pallet 4 may be provided so that the pallet 4 and the application electrode 2 move relatively. Thereby, the workpiece | work 100 with a larger area can be efficiently plasma-processed.
Furthermore, a plurality of workpieces 100 in the form of small pieces may be placed on the pallet 4 for processing, and in this case, the plurality of workpieces 100 can be subjected to plasma processing collectively. As a result, it contributes to the improvement of productivity.

In each of the above embodiments, the case where the pallet 4 and the workpiece 100 are vibrated integrally and the case where the application electrode 2 is vibrated have been described. However, the present invention is not limited to such a case. 2 or at least one of the workpieces 100 may be vibrated. For example, the workpiece 100 may be vibrated alone, or all of the pallet 4, the application electrode 2, and the workpiece 100 are vibrated. It may be.
Furthermore, the voltage applied between the application electrode 2 and the pallet 4 is not limited to a high-frequency voltage, and may be a pulse wave or a microwave, for example.

  Note that, as in each of the above-described embodiments, the pallet 4 may not be provided with the function of the counter electrode, and an electrode serving as the counter electrode of the application electrode 2 may be separately provided. In this case, the counter electrode may be bonded to the lower surface of the pallet 4, and the vibrator 9 may be disposed on the lower surface of the counter electrode via an insulator. The vibrator may be disposed on the upper surface of the counter electrode via the insulator. 9 may be provided, and the upper surface of the vibrator 9 may be bonded to the lower surface of the pallet 4. In the former case, when the piezoelectric body 91 of the vibrator 9 expands and contracts, the insulator, the counter electrode, the pallet 4 and the work 100 arranged on the upper side vibrate, and a sound wave (standing wave) is generated above the work 100. appear. On the other hand, in the latter case, when the piezoelectric body 91 of the vibrator 9 expands and contracts, the pallet 4 and the workpiece 100 arranged on the upper side vibrate, and a sound wave is generated above the workpiece 100.

Next, specific examples of the present invention will be described.
1. Plasma processing of substrate to be processed (Example 1)
The plasma processing apparatus 1 of the first embodiment shown in FIG. 1 is prepared, a work (substrate to be processed) is placed on the pallet 4, and based on the measurement values detected by the temperature detection means 71 and the thickness detection means 72. Then, the frequency adjusting means 74 was operated, and the substrate to be processed was subjected to plasma treatment (etching) under the following conditions for 10 minutes.
The substrate to be processed was a SiO ₂ substrate having a length of 50 mm, a width of 50 mm, and a thickness of 0.5 mm.

The initial conditions for the plasma treatment were as follows.
Applied power: 50W
Frequency of the high-frequency power source 82: 40.68 MHz
Processing gas: CF ₄
Carrier gas: He
Mixing ratio of processing gas and carrier gas: 100: 1
Gas flow rate: 1500sccm
Distance between substrate to be processed and dielectric layer 3: 0.4 mm
Atmosphere: Atmospheric pressure Atmosphere (plasma generation region) temperature: 25 ° C
Constant n (n wavelength): 0.75
Standing wave frequency: 1584441 Hz
The temperature of the atmosphere and the frequency of the standing wave at the end of the plasma treatment were as shown below.
Atmosphere (plasma generation region) temperature: 65 ° C
Standing wave frequency: 1685536Hz

(Example 2)
The substrate to be processed was subjected to plasma processing in the same manner as in Example 1 except that the operation of the thickness detector 72 was omitted.
(Example 3)
The substrate to be processed was subjected to plasma processing in the same manner as in Example 1 except that the operation of the temperature detecting means 71 was omitted.
(Comparative example)
The substrate to be processed was subjected to plasma processing in the same manner as in Example 1 except that the vibration of the vibrator 9 was omitted.

2. Measurement of etching amount of SiO ₂ layer after plasma processing The etching amount on the surface to be processed 110 of the substrate to be processed on which the plasma processing was performed in each of the examples and the comparative examples was measured. This measurement was performed using a film thickness measuring device (“Lambda Ace” manufactured by Dainippon Screen Co., Ltd.).
The results are shown in Table 1.

  As shown in Table 1, in each Example, compared with the etching amount of the to-be-processed surface 110 measured by the comparative example, the etching amount of those to-be-processed surfaces 110 was large. This is because the active species 20 generated in the plasma receives a force due to the acoustic radiation pressure (standing wave) and stays in the vicinity of the surface to be processed 110 for a long time. This result suggests that an appropriate plasma treatment was applied.

In particular, the one in which both the temperature detecting means 71 and the thickness detecting means 72 were operated (Example 1) showed a tendency that the etching amount increased. This is based on the change amount of the change amount and the distance of the temperature, by operating the frequency adjusting unit 74, the moving sections W ₁ of the standing wave W is reliably prevented, as a result, it is treated This result suggests that the surface 110 has been subjected to better plasma treatment.
The surface to be processed 110 of the substrate to be processed is etched in the same manner as in Examples 1 to 3 except that each of the plasma processing apparatuses 1 of the second embodiment and the third embodiment is used. As a result, the same results as described above were obtained.

It is sectional drawing which shows typically 1st Embodiment of the plasma processing apparatus of this invention. It is a schematic diagram which shows the state in which the standing wave has generate | occur | produced between the application electrode with which the plasma processing apparatus shown in FIG. It is a block diagram which shows the circuit structure of the plasma processing apparatus shown in FIG. It is a flowchart of the processing operation with respect to the to-be-processed surface of the workpiece | work by the plasma processing apparatus shown in FIG. It is sectional drawing which shows typically 2nd Embodiment of the plasma processing apparatus of this invention. It is sectional drawing which shows typically 3rd Embodiment of the plasma processing apparatus of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Plasma processing apparatus 2 ... Applied electrode 22 ... Lower surface 20 ... Active species 3 ... Dielectric layer 30 ... Opposite surface 4 ... Pallet 41 ... Concave 42 ... Upper surface 5 ... Moving means 50 ... ... Cylinder 51 ... Cylinder body 52 ... Piston 53 ... Distance detection means 6 ... Table 61 ... Recess 62 ... Upper face 63 ... Lower face 70 ... Control means 71 ... Temperature detection means 72 ... Thickness detection Means 73... Sound thickness detection means 74... Frequency adjustment means 75... Operation unit 8... First circuit 81... Conductor 82 ... High-frequency power supply 83 ... Switch 84 ... Matching box 9. …… Piezoelectric body 92, 93 …… Electrode 94 …… Insulator 10 …… Second circuit 101 …… Conductor 102 …… AC power supply 103 …… Switch 11 …… Gas supply means 1 2. Gas supply pipe 121 ... Branch pipe 13 ... Gas cylinder 14 ... Regulator 15 ... Valve 16 ... Nozzle 100 ... Workpiece 110 ... Surface to be treated

Claims (12)

A first electrode and a second electrode arranged to face each other across the workpiece;
Gas supply means for supplying a gas for generating plasma on the surface to be processed of the workpiece;
A power supply unit that applies a voltage between the first electrode and the second electrode so as to activate the gas supplied by the gas supply means to generate plasma;
A plasma processing apparatus for processing the surface to be processed with plasma generated by the operation of the gas supply means and the power supply unit,
A vibrator that generates a vibration wave in a plasma generation region where the plasma is generated by vibrating at least one of the first electrode, the second electrode, and the workpiece;
Frequency adjusting means for adjusting the frequency of the vibration wave by adjusting the frequency of the vibrator;
Control means for controlling the operation of the frequency adjusting means,
A plasma processing apparatus, wherein the control means operates the frequency adjusting means to adjust the frequency of the vibration wave. Distance detecting means for detecting a distance between a surface to be processed of the workpiece and the surface of the first electrode or the second electrode facing the surface to be processed;
Moving means for defining a separation distance between the surface to be processed of the workpiece and the facing surface by moving the first electrode or the second electrode;
Prior to processing the surface to be processed of the workpiece, based on the information from the distance detection means, the control means operates the moving means to adjust the separation distance, whereby the separation distance is set. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is set to a magnitude at which a standing wave is generated between a surface to be processed of the workpiece and the facing surface.   The plasma processing apparatus according to claim 2, wherein the standing wave is generated between the surface to be processed of the workpiece and the facing surface in a direction substantially orthogonal to the surface to be processed of the workpiece.   The plasma processing apparatus according to claim 2, wherein the control unit controls the node of the standing wave to be positioned on a surface to be processed of the workpiece. A temperature detecting means for detecting a temperature change in a region where the plasma is generated during processing of the surface to be processed of the workpiece by the plasma;
The control means prevents the movement of the node of the standing wave from the surface to be processed by operating the frequency adjusting means based on the temperature change detected by the temperature detecting means. Item 5. The plasma processing apparatus according to Item 4. Thickness detection means for detecting a change in thickness that occurs during processing of the surface to be processed of the workpiece by the plasma,
The control means operates the frequency adjusting means based on the change in the thickness detected by the thickness detection means, thereby moving the standing wave node from the surface to be processed of the workpiece. The plasma processing apparatus according to claim 4 or 5, which is prevented. A sound pressure detecting means for detecting a sound pressure level between the surface to be processed of the workpiece and the facing surface;
7. The plasma processing apparatus according to claim 2, wherein the sound pressure means detects a position of a node of the standing wave between the surface to be processed and the facing surface. The plasma processing apparatus according to claim 2, wherein the standing wave has a frequency set in a range of 1 × 10 ⁵ to 1 × 10 ⁸ Hz.   The plasma processing apparatus according to any one of claims 2 to 8, wherein a standing wave is generated between the surface to be processed and the opposing surface after plasma is generated between the surface to be processed and the opposing surface. . The workpiece is placed on the first electrode;
The plasma processing apparatus according to claim 1, wherein the first electrode and the workpiece are vibrated integrally by the vibrator. The workpiece is placed on the first electrode;
The plasma processing apparatus according to claim 1, wherein the second electrode is vibrated by the vibrator.   The plasma according to claim 10 or 11, wherein the gas supply means includes at least one nozzle that is provided through the second electrode and jets the gas between the second electrode and the workpiece. Processing equipment.

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