JP2008135296A - Plasma treatment device, and method of surface treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device to capture foreign matters generated by plasma and to prevent arc discharge, and to provide a surface treatment method of treating a treated face of a work by using this. <P>SOLUTION: The plasma treatment device 1 is equipped with a mutually opposed pair of electrodes 2, 3 relatively movable to the work 10, a power supply circuit 7 equipped with a power supply 72 to apply a voltage between the pair of electrodes 2, 3, a gas supply means 8 to supply a treated gas for plasma formation between the pair of electrodes 2, 3, and a plasma injection part 5 to inject plasma toward the treated face 101 of the work 10. This is the plasma treatment device 1 constituted so that by applying the voltage while supplying the treated gas between the pair of electrodes 2, 3, the treated gas is activated to form the plasma, and the treated face 101 of the work 10 is treated by the plasma. This has a foreign matter capturing part 9 composed of a porous insulating material to capture the foreign matters 40 generated by formation of the plasma at the plasma injection part 5 or in its vicinity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus and a surface treatment method.

When processing the surface of a material, a reactive gas is supplied to an electrode to which a voltage or a high frequency is applied, a radical based on the reactive gas is generated, and a product generated by a radical reaction between the radical and the workpiece is removed. A method of processing is used.
As an apparatus for performing such processing, for example, a plasma apparatus provided with a metal mesh at a gas outlet containing plasma is known (for example, Patent Document 1).

In addition, in an apparatus for performing processing by guiding plasma generated between a voltage application electrode and a ground electrode to a base material, a plasma apparatus having an insulating spacer between the voltage application electrode and the base material is known (for example, Patent Document 2).
However, although these plasma processing apparatuses capture ions and electrons in the plasma, they cannot sufficiently capture foreign matter generated by the plasma. As a result, there is a problem that the work is contaminated by the gas containing foreign matter being ejected onto the work.

On the other hand, a plasma processing apparatus provided with a magnetic duct and an electric field filter so as to capture and remove charged particles contained in plasma is known (for example, Patent Document 3).
There is also known a plasma processing apparatus that transports and removes dust contained in plasma using a traveling wave electric field formed by a potential distribution by a multiphase AC voltage (for example, Patent Document 4).
However, these plasma processing apparatuses require a separate power supply and electrodes for capturing and removing foreign substances. For this reason, there are problems that the apparatus configuration is complicated, the apparatus handling is complicated, and the processing equipment is expensive.

JP 7-245192 A Japanese Patent Laid-Open No. 2003-1000064 JP 2002-25794 A JP 2004-259832 A

  An object of the present invention is to provide a plasma processing apparatus that captures foreign matter generated by plasma and prevents arc discharge, and a surface processing method for processing a surface to be processed of a workpiece using the plasma processing apparatus.

Such an object is achieved by the present invention described below.
The plasma processing apparatus of the present invention includes a pair of electrodes facing each other and movable relative to a workpiece,
A power supply circuit comprising a power supply for applying a voltage between the pair of electrodes;
Gas supply means for supplying a processing gas for generating the plasma between the pair of electrodes;
A plasma ejection part that ejects the plasma toward the surface to be processed of the workpiece,
By applying the voltage while supplying the processing gas between the pair of electrodes, the processing gas is activated to generate plasma, and the surface to be processed of the workpiece is processed by the plasma. A plasma processing apparatus configured as follows:
A foreign matter trapping portion made of a porous insulating material that traps the foreign matter generated by the generation of the plasma is provided at or near the plasma ejection portion.
Thereby, since the foreign material generated by the plasma can be captured, contamination of the workpiece by the foreign material can be prevented. Moreover, since the insulating material is used for the foreign matter capturing part, it is possible to prevent the workpiece from being damaged by the arc discharge.

In the plasma processing apparatus of the present invention, the pair of electrodes are preferably arranged along a direction orthogonal to the workpiece.
As a result, the processing gas is uniformly ejected to the surface to be processed of the workpiece, so that uniform plasma processing can be performed.
In the plasma processing apparatus of this invention, it is preferable that the said foreign material capture | acquisition part is comprised with the laminated body by which the said insulating material was laminated | stacked as two or more insulating material layers.
Thereby, since physical and chemical properties can be changed in each insulating material layer, foreign substances having different physical and chemical properties can be captured in each insulating material layer.

In the plasma processing apparatus of the present invention, it is preferable that the foreign substance capturing unit is configured such that the insulating material is made of different types of materials in each of the insulating material layers.
As a result, materials having different physical and chemical properties can be used for each insulating material layer, so that foreign materials having different physical and chemical properties can be efficiently captured by each insulating material layer.
In the plasma processing apparatus of this invention, it is preferable that the said insulating material is comprised with ceramics.
Thereby, arc discharge can be prevented more reliably and damage to the workpiece can be prevented.

In the plasma processing apparatus of the present invention, it is preferable that the foreign matter trapping portion has a different pore diameter in each insulating material layer.
As a result, foreign substances having different particle sizes can be captured in each insulating material layer, so that foreign substances can be efficiently captured, and a processing gas containing no foreign substances can be reliably ejected.
In the plasma processing apparatus of the present invention, the foreign matter capturing part includes one insulating material layer among the two or more insulating material layers, and one insulating material positioned on the pair of electrodes. The insulating material layer preferably includes at least one set of the insulating material layers in which the former pore diameter is smaller than the latter pore diameter.
Thereby, since the foreign material having a large particle diameter is sequentially captured by the insulating material layer, the foreign material can be efficiently captured, and the processing gas efficiently passes through the insulating material layer.

In the plasma processing apparatus of the present invention, the foreign matter capturing part includes one insulating material layer among the two or more insulating material layers, and one insulating material positioned on the pair of electrodes. The insulating material layer preferably includes at least one set of the insulating material layers in which the former porosity is smaller than the latter porosity.
Thereby, since the foreign material having a large particle diameter is sequentially captured by the insulating material layer, the foreign material can be efficiently captured, and the processing gas efficiently passes through the insulating material layer.

In the plasma processing apparatus of the present invention, the porous material preferably has a pore diameter of 200 μm or less.
As a result, foreign matter is reliably captured and the processing gas passes through reliably, so that plasma processing can be performed while preventing contamination of the workpiece surface.
In the plasma processing apparatus of the present invention, the porous material preferably has a porosity of 30 to 85%.
Thereby, since the holes exist in each insulating material layer without excess or deficiency, the removal rate of foreign matters is improved, and the passing rate of the processing gas is also improved.
In the plasma processing apparatus of the present invention, it is preferable that each of the pair of electrodes is covered with a dielectric portion on a surface side facing at least one of the electrodes.
Thereby, since the metal etc. which are electrodes are not exposed between the 1st electrode and the 2nd electrode, arc discharge can be prevented and an electric field can be generated uniformly.

The surface treatment method of the present invention includes a pair of electrodes facing each other,
A power supply circuit comprising a power supply for applying a voltage between the pair of electrodes;
Gas supply means for supplying a processing gas for generating the plasma between the pair of electrodes;
A plasma ejection part for ejecting the plasma toward the surface of the workpiece;
A plasma processing apparatus comprising a foreign matter trapping portion made of a porous insulating material that traps foreign matter generated by the generation of the plasma at or near the plasma ejection portion,
A surface that activates the processing gas to generate plasma by supplying the processing gas while supplying the processing gas between the pair of electrodes, and processes the surface to be processed of the workpiece by the plasma A processing method,
The foreign matter generated by the generation of the plasma is captured by the foreign matter capturing unit, and the surface to be processed of the workpiece is processed by the plasma after passing through the foreign matter capturing unit.
Thereby, since the process gas which does not contain a foreign material is ejected to the to-be-processed surface of a workpiece | work, the surface treatment without the contamination by a foreign material can be performed.
In the surface treatment method of the present invention, it is preferable to treat the surface to be treated of the workpiece while relatively moving the workpiece and the plasma processing apparatus.
Thereby, the plasma processing can be easily performed on the entire surface to be processed of the workpiece.

Hereinafter, a plasma processing apparatus of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
(1) Plasma Processing Apparatus FIG. 1 is a longitudinal sectional view showing a longitudinal sectional view showing a schematic configuration of a first embodiment of a plasma processing apparatus of the present invention.

In the following description, the upper side in FIG. 1 is referred to as “upper” and the lower side is referred to as “lower”.
The plasma processing apparatus 1 includes a pair of opposing electrodes (a first electrode 2 and a second electrode 3) that are movable relative to a workpiece 10 and a dielectric that defines a gas flow path. A voltage between the pair of electrodes, the plasma ejection section 5 for ejecting plasma toward the surface to be processed 101 of the workpiece 10, the processing gas introduction port 6 for introducing the processing gas between the pair of electrodes, and the pair of electrodes. A power supply circuit 7 having a power supply 72 to be applied, a gas supply means 8 for supplying a processing gas for generating plasma, and a foreign matter trapping part 9 for catching foreign matter 40 generated by the generation of plasma are provided.
The plasma processing apparatus 1 activates a processing gas by applying a voltage between the first electrode 2 and the second electrode 3 to generate plasma, and the surface to be processed 101 of the workpiece 10 is processed by the plasma. It is a device to do.

Hereinafter, the configuration of each part of the plasma processing apparatus 1 will be described.
The first electrode 2 is disposed along a direction orthogonal to the workpiece, and is disposed opposite to the second electrode 3. And since the 1st electrode 2 is an electrode for applying a voltage, it is connected to the power supply 72 via the conducting wire 71, in order to take an electrical connection.
Although it does not specifically limit as a constituent material of the 1st electrode 2, For example, simple metals, such as copper, aluminum, iron, and silver, various alloys, such as stainless steel, brass, and aluminum alloy, intermetallic compounds, various carbon materials, etc. Is mentioned.
In addition, the shape of the 1st electrode 2 is not specifically limited, for example, flat shape, cylindrical shape, etc.

The second electrode 3 is an electrode having a function as a ground electrode, and is directly grounded via a conducting wire 71.
The shape and constituent material of the second electrode 3 are not particularly limited, as with the first electrode 2.
Each of the first electrode 2 and the second electrode 3 is formed with a dielectric portion 4 made of a dielectric material on the surface where the first electrode 2 and the second electrode 3 face each other. Yes. And the dielectric material part 4 has a function as a pair of side wall which defines the flow path of gas.

  As described above, the dielectric portions 4 are formed on the opposing surfaces of the first electrode 2 and the second electrode 3, so that the electrode is interposed between the first electrode 2 and the second electrode 3. Therefore, the electric field can be generated uniformly between the electrodes. Further, an increase in impedance can be prevented, a desired discharge can be generated at a relatively low voltage, and plasma can be generated reliably. Furthermore, it is possible to prevent dielectric breakdown during voltage application, suitably prevent arc discharge from occurring, and obtain glow-like stable discharge.

  The dielectric portion 4 has a length in a direction perpendicular to the workpiece 10 (vertical direction in FIG. 1) from the length of each of the first electrode 2 and the second electrode 3 in the direction perpendicular to the workpiece 10. And is formed to extend in a direction perpendicular to the workpiece 10. As described above, since the dielectric portion 4 is formed so as to extend in a direction orthogonal to the workpiece 10, the turbulence of the processing gas introduced into the space between the dielectric portions 4 can be prevented, and the flow of the processing gas can be prevented. Can be controlled smoothly. Further, the generated plasma can be efficiently supplied to the plasma ejection unit 5.

A processing gas supplied from the gas supply unit 8 is introduced between the first electrode 2 and the second electrode 3 (hereinafter referred to as “plasma generation region 30”) at the upper end of the dielectric unit 4. A processing gas inlet 6 is provided. At the lower end portion of the dielectric portion 4, a plasma ejection portion 5 is opened and provided as desired for the workpiece.
In addition, the foreign material capture | acquisition part 9 currently formed in the plasma ejection part 5 is demonstrated in detail later.

Examples of the shape of the dielectric portion 4 include a flat plate shape and a cylindrical shape, and a flat plate shape is preferable. Thereby, since the facing surfaces of the first electrode 2 and the second electrode 3 are formed substantially flat, the flow of the processing gas can be reliably controlled.
Examples of the constituent material of the dielectric portion 4 include various plastics such as polytetrafluoroethylene and polyethylene terephthalate, various glasses such as quartz glass, and inorganic oxides. Examples of the inorganic oxide include metal oxides such as Al ₂ O ₃ (alumina), SiO ₂ , ZrO ₂ , TiO ₂ and ZnO, nitrides such as silicon nitride and aluminum nitride, carbides such as silicon carbide, phosphorus Examples thereof include dielectric materials such as phosphates such as sodium phosphate, potassium phosphate and zirconium phosphate, and complex oxides such as BaTiO ₃ (barium titanate). Of these, metal oxides are preferred, and alumina is more preferred. By using such a material, the occurrence of arc discharge in an electric field can be prevented more reliably.

In addition, as long as the dielectric part 4 has covered the opposing surface of the 1st electrode 2 and the 2nd electrode 3, it has not covered each outer peripheral surface of the 1st electrode 2 and the 2nd electrode 3 May be. Thereby, since electrode materials, such as a metal, are not exposed to the plasma generation area | region 30, damage of the workpiece | work 10 by the concentration of an electric field, etc. can be prevented efficiently with a small amount of dielectric materials.
The first electrode 2 and the second electrode 3 are arranged at a position away from the workpiece 10 by a predetermined distance (a length indicated by h ₁ in FIG. 1). The distance h ₁ is appropriately set in consideration of the output of the power supply circuit 7, the type of plasma processing applied to the workpiece 10, and the like. In the case of performing plasma treatment at normal pressure, the thickness is more preferably 500 mm or less in view of impedance, gas flow rate, lifetime of radicals generated by plasma, and the like. Since the distance h ₁ is within such a range, the distance from the plasma generation region 30 to the workpiece 10 becomes an optimum distance, and thus the plasma reaches the processing surface 101 without reducing the generated plasma force. be able to.

Also, foreign body capturing portion 9 (in FIG. 1, the length indicated by h ₂₎ a predetermined distance from the workpiece 10 is placed on a position apart. Such distance h ₂ is output and the power supply circuit 7 is appropriately set in consideration of the type of plasma treatment performed on the workpiece 10. When the plasma treatment is performed at normal pressure, the thickness is more preferably 100 mm or less in consideration of impedance, gas flow rate, lifetime of radicals generated by plasma, gas pressure, and the like. Thereby, since the distance from the foreign material capture | acquisition part 9 to the workpiece | work 10 becomes an optimal distance, desired plasma processing can be performed reliably.

  The power supply circuit 7 includes a high-frequency power source 72 that applies a voltage between the first electrode 2 and the second electrode 3, a conductive wire 71 that conducts the high-frequency power source 72 and the first electrode 2, and a second electrode 3 is provided. Although not shown, a matching circuit (impedance matching circuit) for the power to be supplied, frequency adjusting means (circuit) for changing the frequency of the high-frequency power source 72, and the maximum value (amplitude) of the applied voltage of the high-frequency power source 72 are changed. Voltage adjustment means (circuit) and the like are installed as necessary. Thereby, the processing conditions of the plasma processing with respect to the workpiece | work 10 can be adjusted suitably.

A high-frequency power source 72 is connected to the first electrode 2 via a conducting wire 71, thereby configuring a power supply circuit 7. A part of the power supply circuit 7, that is, the conductive wire 71 on the second electrode 3 side is grounded (grounded).
When plasma processing is performed on the workpiece 10, the high frequency power source 72 is activated and a voltage is applied between the first electrode 2 and the second electrode 3. At this time, an electric field is generated between the first electrode 2 and the second electrode 3, and when gas is supplied, discharge occurs and plasma is generated.

The frequency of the high frequency power supply 72 is not particularly limited, but is preferably 1 KHz to 70 MHz, and more preferably 10 to 40 MHz.
The gas supply unit 8 supplies a processing gas for generating plasma to the plasma generation region 30. This gas supply means 8 includes a gas cylinder (gas supply source) 81 that is charged and supplied with a predetermined gas, a mass flow controller (flow rate adjustment means) 82 that adjusts the flow rate of the gas supplied from the gas cylinder 81, and a mass flow controller 82. On the downstream end side, a valve (channel opening / closing means) 83 that opens and closes a flow path in the processing gas pipe 84 and a processing gas pipe 84 connected to the processing gas inlet 6 are provided.

Such a gas supply means 8 sends out a predetermined gas from a gas cylinder 81 and adjusts the flow rate by a mass flow controller 82. Then, the processing gas is introduced (supplied) from the processing gas inlet 6 into the space between the dielectric parts 4 (plasma generation region 30) through the processing gas pipe 84.
Various gases can be used as the gas (processing gas) used for such plasma processing depending on the processing purpose.

(A) For the purpose of etching or dicing the surface to be processed 101 of the workpiece 10, for example, fluorine such as CF ₄ , C ₂ F ₆ , C ₃ F ₆ , C ₄ F ₈ , CClF ₃ , SF _6, etc. Various halogen-based gases such as an atom-containing compound gas and a chlorine atom-containing compound gas such as Cl ₂ , BCl ₃ , and CCl ₄ are used.
(B) For the purpose of heating the surface to be processed 101 of the workpiece 10, for example, N ₂ , O ₂ or the like is used.

(C) For the purpose of making the treated surface 101 of the workpiece 10 water repellent (liquid repellent), for example, the fluorine atom-containing compound gas is used.
(D) For the purpose of making the treated surface 101 of the workpiece 10 hydrophilic (lyophilic), for example, O ₃ , H ₂ O, oxygen atom-containing compounds such as air, nitrogen such as N ₂ and NH ₃ Atom-containing compounds, sulfur atom-containing compounds 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 101 of the workpiece | work 10, a 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.

(E) When it is intended to add an electrical or optical function to the surface to be processed 101 of the workpiece 10, a metal oxide thin film such as SiO ₂ , TiO ₂ or SnO ₂ is applied to the surface to be processed 101 of the workpiece 10. In order to form them, metal metal-hydrogen compounds such as Si, Ti, Sn, metal-halogen compounds, metal alkoxides (organometallic compounds) and the like are used.
(F) For the purpose of resist treatment or removal of organic contamination, for example, oxygen-based gas is used.

As such a processing gas, a mixed gas composed of the processing gas and the carrier gas (hereinafter also simply referred to as “gas”) is generally used. The “carrier gas” refers to a gas introduced for starting discharge and maintaining discharge.
In this case, the gas cylinder 81 may be filled with a mixed gas (processing gas + carrier gas), or the processing gas and the carrier gas may be filled in separate gas cylinders, and these gas cylinders 81 may be in the middle of the processing gas pipe 84. May be mixed at a predetermined mixing ratio.

As the carrier gas, a rare gas such as He, Ne, Ar, or Xe can be used. These can be used alone or in a mixed form of two or more.
The ratio (mixing ratio) of the processing gas in the mixed gas is slightly different depending on the purpose of the processing and is not particularly limited. For example, the ratio of the processing gas in the mixed gas is preferably 1 to 10%. More preferably, it is 10%. Thereby, discharge is efficiently started, and a desired plasma treatment can be performed with the treatment gas.
The flow rate of the gas to be supplied is appropriately determined according to the type of gas, the purpose of processing, the degree of processing, and the like. Usually, it is preferably about 30 SCCM to 50 SLM. Thereby, since plasma is efficiently generated in the plasma generation region 30, fine processing can be performed.

The plasma generated in the plasma generation region 30 comes into contact with the dielectric portion 4 existing in the plasma generation region 30 to generate foreign material (particles) 40 derived from the material constituting the dielectric portion 4. The foreign matter 40 flows to the plasma ejection part 5 together with the processing gas, and is ejected from the plasma ejection part 5 toward the processing surface 101 of the workpiece 10 together with the processing gas. When the foreign matter 40 reaches the processing surface 101, the foreign matter 40 adheres to the processing surface 101. As a result, the surface to be processed 101 of the workpiece 10 is contaminated by the foreign matter 40.
For this reason, it is preferable to provide a foreign matter catching section 9 for catching the foreign matter 40 after the plasma is generated and before the plasma reaches the processing surface 101 of the workpiece 10.

Hereinafter, the foreign material capturing unit 9 will be described in detail.
In the plasma processing apparatus 1 of the present embodiment, the foreign substance capturing unit 9 is opposed to the work 10 so as to cover the plasma ejection unit 5 at the lower end of the dielectric unit 4, that is, the plasma ejection unit 5 (or its vicinity). Is provided.
Since the foreign matter catching part 9 is provided in the plasma ejection part 5, the processing gas always passes through the foreign matter catching part 9, so that the foreign matter catching part 9 catches the foreign matter 40 and contaminates the surface 101 to be processed of the workpiece 10. Can be prevented.

The foreign matter capturing unit 9 includes a porous insulating material (dielectric) layer 91 having a function of capturing the foreign matter 40 generated by plasma, and a support member 95 that supports the insulating material layer 91 on the plasma processing apparatus 1. And a net-like member 96.
Examples of the insulating material constituting the insulating material layer 91 include various glasses such as quartz glass, metal oxides such as Al ₂ O ₃ (alumina), SiO ₂ , ZrO ₂ , TiO ₂ , and ZnO, silicon nitride, Ceramics such as metal nitrides such as aluminum nitride, metal carbides such as silicon carbide, phosphates such as sodium phosphate, potassium phosphate and zirconium phosphate, and complex oxides such as BaTiO ₃ (barium titanate), polytetra Examples thereof include resin materials having heat resistance such as fluoroethylene and polyethylene terephthalate.

When a conductive material layer made of a conductive material such as a metal is used for the foreign matter capturing part 9, arc discharge occurs in the conductive material layer, and the surface 101 of the workpiece 10 is damaged by the arc discharge, Or excessive processing may be performed.
Moreover, there is a possibility that foreign matters derived from the conductive material may be generated on the lower surface side of the conductive material layer due to arc discharge of the conductive material layer. Then, the foreign matter may reach and adhere to the processing surface 101 of the workpiece 10 together with the processing gas, and the processing surface 101 may be contaminated.

Furthermore, the conductive material is oxidized by arc discharge of the conductive material layer, and the discharge state may change. Therefore, there is a possibility that the surface 101 to be processed is not uniformly plasma-treated due to a change in the discharge state.
However, in the present invention, the use of the insulating material layer 91 made of an insulating material for the foreign material capturing portion 9 does not cause the above-described problem when the conductive material layer is used. Can be processed satisfactorily and uniformly.

Examples of the insulating material constituting the insulating material layer 91 include those described above. In particular, a metal oxide is preferably used, and alumina is more preferably used. By using a metal oxide, particularly alumina, the dielectric constant is particularly high, so that the occurrence of arc discharge in an electric field can be prevented more reliably.
A number of holes are formed in the porous insulating material layer 91, and the holes form continuous holes.

And the porosity of the hole is preferably 30 to 85%, more preferably 45 to 70%.
If the porosity is too small, the rate at which the foreign matter 40 is captured (removal rate of the foreign matter 40) is improved, but the permeability of the insulating material layer 91 for the processing gas is reduced, so If the pressure of the processing gas supplied to the gas flow path is not increased, a sufficient amount of plasma cannot be supplied to the surface 101 to be processed.

On the other hand, if the porosity is too large, the permeability of the processing gas is improved, but the removal rate of the foreign matter 40 may be reduced.
The porosity can be measured by the Archimedes method, the X-ray reflectivity measurement method, or the like.
Further, the hole diameter (average) is not particularly limited, but is set in consideration of the average particle diameter of the foreign matter 40. For example, it is preferably 200 μm or less, and more preferably 20 μm or less.
If the hole diameter is too small, the removal rate of the foreign matter 40 is improved, but the permeability of the insulating material layer 91 of the processing gas is lowered, so the pressure of the processing gas supplied between the dielectric parts 4 (processing gas flow path). If the height is not increased, a sufficient amount of plasma cannot be supplied to the surface 101 to be processed.

On the other hand, when the hole diameter is too large, the permeability of the processing gas is improved, but the removal rate of the foreign matter 40 may be reduced.
Note that the holes are preferably formed uniformly dispersed in the insulating material layer 91.
The thickness _{T 1} of the insulating material layer 91 is preferably 100mm or less, and more preferably 10mm or less.
When the thickness of the insulating material layer 91 is small, the permeability of the processing gas is improved, but the removal rate of the foreign matter 40 may be reduced.

On the other hand, if the thickness of the insulating material layer 91 is too large, the removal rate of the foreign matter 40 is improved, but the permeability of the insulating material layer 91 of the processing gas is lowered, so that the dielectric material 4 (processing gas flow) Unless the pressure of the processing gas supplied to the channel) is increased, a sufficient amount of plasma cannot be supplied to the surface 101 to be processed.
In addition, although the shape of the insulating material layer 91 is not specifically limited, In this embodiment, it is comprised by flat form.

The support member 95 supports the insulating material layer 91 so as to sandwich the edge of the insulating material layer 91. The support member 95 is detachably provided on the insulating material layer 91. Thereby, the insulating material layer 91 can be easily removed, and replacement of the insulating material layer 91 described later can be facilitated.
A mesh member 96 is provided on the lower surface of the insulating material layer 91 on which the support member 95 is not sandwiched. Thereby, the fall of the insulating material layer 91 can be prevented reliably.

The mesh member 96 is detachably attached to the support member 95. Therefore, by removing the mesh member 96 from the support member 95, the insulating material layer 91 described later can be easily replaced.
The material constituting the support member 95 and the mesh member 96 is made of an insulating material so that arc discharge and foreign matter 40 are not generated. Specifically, the same material as the material of the insulating material layer 91 is used.

The insulating material layer 91 of the foreign material capturing part 9 can be replaced with an insulating material layer 91 prepared separately.
That is, when the processing of the processing target surface 101 of the workpiece 10 is repeatedly performed using the plasma processing apparatus 1, the foreign material 40 is captured every time the processing gas passes through the insulating material layer 91 of the foreign material capturing unit 9. Therefore, the hole of the insulating material layer 91 is blocked by the foreign material 40, and the amount of the processing gas that passes through the insulating material layer 91 gradually decreases. Finally, the trapped foreign matter 40 may block most of the holes, and the processing gas may not pass through the insulating material layer 91. That is, there is a possibility that the surface to be processed 101 cannot be subjected to plasma processing. In such a case, it is preferable to replace the insulating material layer 91 with a new insulating material layer 91 in order to restore the plasma processing performance.

In order to replace the insulating material layer 91, for example, the insulating material layer 91 and the mesh member 96 are detached from the supporting member 95 and removed while the supporting member 95 is attached to the dielectric portion 4. Then, a new insulating material layer 91 separately prepared and the removed mesh member 96 can be attached to the support member 95.
Note that the removed insulating material layer 91 may be cleaned, attached to the support member 95 again, and reused without replacing the insulating material layer 91.
The foreign matter capturing unit 9 described above captures the foreign matter 40 generated by the plasma. However, the foreign matter 40 derived from the processing gas contained in the processing gas and the foreign matter 40 entering from the outside of the plasma processing apparatus 1 are also included. Naturally it can be captured.

Next, another configuration example of the foreign substance capturing unit 9 will be described.
As another configuration example of the foreign matter capturing unit 9, an insulating material can be laminated in two or more layers. In this case, the conditions such as the material, pore diameter, porosity, and thickness of each layer may be the same, or part or all may be different. Hereinafter, this configuration example will be described with reference to FIG.
FIG. 2 is a longitudinal sectional view showing another configuration example of the foreign matter trapping part 9 of the plasma processing apparatus 1 of the present invention. In the following description, the upper side in FIG. 2 is referred to as “upper” and the lower side is referred to as “lower”.

As shown in FIG. 2, the foreign material capturing unit 9 has a first insulating material layer in which the insulating material is laminated in two layers (a first insulating material layer 92 and a second insulating material layer 93). The hole diameter of the second insulating material layer 93 is smaller than the hole diameter of 92.
As described above, since the hole diameter of the second insulating material layer 93 is smaller than the hole diameter of the first insulating material layer 92, first, in the first insulating material layer 92, The foreign material 40 having a particle size larger than the hole diameter of the insulating material layer 92 is captured, and then in the second insulating material layer 93, the second insulating material layer 93 that has passed through the first insulating material layer 92. The foreign matter 40 having a particle size larger than the pore size is captured.

Therefore, compared with the case where one layer of the insulating material layer 91 described above is used, the permeability of the processing gas can be improved and the foreign matters 40 having different particle diameters can be efficiently captured. As a result, the removal rate of the foreign matter 40 is improved.
Further, the clogging of the first insulating material layer 92 and the second insulating material layer 93 due to the foreign matter 40 can be suppressed, and the first insulating material layer 92 and the second insulating material layer 93 can be suppressed. Long life.

Each of the first insulating material layer 92 and the second insulating material layer 93 preferably has a hole diameter in the above-described range, but the first insulating material layer 92 has a hole diameter of 100 to 200 μm. It is preferable that it is 100-180 micrometers.
If the hole diameter of the first insulating material layer 92 is too smaller than the lower limit value, the hole diameter of the first insulating material layer 92 may be equal to or less than the hole diameter of the second insulating material layer 93. Yes, there is a risk that the removal rate of the foreign matter 40 and the processing gas permeability may be reduced.
On the other hand, the hole diameter of the second insulating material layer 93 smaller than the hole diameter of the first insulating material layer 92 is preferably 100 μm or less, and more preferably 50 μm or less.

If the hole diameter of the second insulating material layer 93 is too larger than the upper limit value, the hole diameter of the second insulating material layer 93 may be equal to or larger than the hole diameter of the first insulating material layer 92. Yes, there is a risk that the removal rate of the foreign matter 40 and the processing gas permeability may be reduced.
In addition, as another configuration example of the foreign matter capturing unit 9, the foreign matter capturing unit 9 includes the first insulating material layer 92 and the first insulating material layer 93 regardless of the size of the respective holes. It is preferable that the porosity of the second insulating material layer 93 is smaller than the porosity of the conductive material layer 92.

By forming the foreign matter catching portion 9 in this way, first, the foreign matter 40 having a large particle diameter is caught in the first insulating material layer 92, and then the first insulating material in the second insulating material layer 93. A small particle size foreign material 40 that is not captured by the layer 92 is captured.
Therefore, compared with the case where one layer of the insulating material layer 91 described above is used, the permeability of the processing gas can be improved and the foreign matters 40 having different particle diameters can be efficiently captured. As a result, the removal rate of the foreign matter 40 is improved.

Further, the clogging of the first insulating material layer 92 and the second insulating material layer 93 due to the foreign matter 40 can be suppressed, and the first insulating material layer 92 and the second insulating material layer 93 can be suppressed. Long life.
Note that the porosity of the first insulating material layer 92 is preferably 60 to 85%, and more preferably 60 to 80%.

If the porosity of the first insulating material layer 92 is too smaller than the lower limit value, the porosity of the first insulating material layer 92 is less than or equal to the porosity of the second insulating material layer 93. There is a possibility that the foreign matter 40 removal rate is lowered and the processing gas permeability is lowered.
On the other hand, the porosity of the second insulating material layer 93 is preferably 30 to 60%, and more preferably 45 to 60%.

If the porosity of the second insulating material layer 93 is too larger than the upper limit value, the porosity of the second insulating material layer 93 is equal to the porosity of the first insulating material layer 92. There is a possibility of the above, and there is a possibility that the foreign matter 40 removal rate is lowered and the processing gas permeability is lowered.
In addition, as another configuration example of the foreign matter capturing unit 9, the foreign matter capturing unit 9 includes the first insulating material layer 92 and the first insulating material layer 93 regardless of the size of the respective holes. The thickness of the second insulating material layer 93 may be formed thinner than the thickness of the conductive material layer 92.

By forming the foreign matter catching portion 9 in this way, first, the foreign matter 40 having a large particle diameter is caught in the first insulating material layer 92, and then the first insulating material in the second insulating material layer 93. A small particle size foreign material 40 that is not captured by the layer 92 is captured.
Therefore, compared with the case where one layer of the insulating material layer 91 described above is used, the permeability of the processing gas can be improved and the foreign matters 40 having different particle diameters can be efficiently captured. As a result, the removal rate of the foreign matter 40 is improved.

Further, the clogging of the first insulating material layer 92 and the second insulating material layer 93 due to the foreign matter 40 can be suppressed, and the first insulating material layer 92 and the second insulating material layer 93 can be suppressed. Long life.
The thickness _{T 2} of the first insulating material layer 92 is preferably 100mm or less, more preferably 5mm or less.

If the thickness T ₂ of the first insulating material layer 92 is too small than the lower limit, the thickness of the first layer of insulating material 92, the thickness and the same or less of the second insulating material layer 93 There is a possibility that the foreign matter 40 removal rate is lowered and the processing gas permeability is lowered.
On the other hand, the thickness of the second insulating material layer 93 smaller than the thickness of the first insulating material layer 92 is preferably 10 mm or less, more preferably 3 mm or less.

If the hole diameter of the second insulating material layer 93 is too larger than the upper limit value, the thickness of the second insulating material layer 93 may be equal to or greater than the thickness of the first insulating material layer 92. There is a risk that the removal rate of the foreign matter 40 and the processing gas permeability may be reduced.
The first insulating material layer 92 and the second insulating material layer 93 described above have the first insulating property in order to obtain the foreign matter trapping portion 9 that forms different hole diameters, porosity or thicknesses. It is preferable that the material layer 92 and the second insulating material layer 93 are made of materials of different types (compositions).
As described above, since different materials are used for the insulating material layers 92 and 93, materials having different properties such as hardness and dielectric constant can be used for the insulating material layers 92 and 93. It is possible to obtain a desired foreign matter capturing part 9 in which the insulating material layer 92 and the second insulating material layer 93 are different in at least one of the hole diameter, the porosity, and the thickness.

Specific examples of the material used for each of the first insulating material layer 92 and the second insulating material layer 93 include the materials described in the insulating material layer 91, which are appropriately selected depending on the above conditions. What is necessary is just to combine.
For example, in the case of the foreign material capturing part 9 in which the hole diameter of the second insulating material layer 93 is smaller than the hole diameter of the first insulating material layer 92, the strength of the insulating material layer 93 is reduced if the hole diameter is large. It is preferable to use alumina, which is a material having high strength, for the insulating material layer 93. On the other hand, since the strength of the insulating material layer 92 increases when the hole diameter is small, it is preferable to use titanium oxide, which is a material having relatively low strength, for the insulating material layer 92.

  Similarly, in the case of the foreign matter trapping part 9 in which the porosity of the second insulating material layer 93 is larger than the porosity of the first insulating material layer 92, the strength of the insulating material layer 93 is increased when the porosity is large. Therefore, it is preferable to use alumina, which is a material having a relatively high strength, for the insulating material layer 92. On the other hand, when the porosity is small, the strength of the insulating material layer 93 is also increased. Therefore, it is preferable to use titanium oxide, which is a material having a relatively low strength, for the insulating material layer 93.

  Further, in the case of the foreign matter trapping part 9 in which the thickness of the second insulating material layer 93 is smaller than the thickness of the first insulating material layer 92, the strength of the insulating material layer 93 is reduced if the thickness is small. It is preferable to use alumina, which is a material having a relatively high strength, for the insulating material layer 93. On the other hand, since the strength of the insulating material layer 92 increases as the thickness increases, it is preferable to use titanium oxide, which is a material having relatively low strength, for the insulating material layer 92.

In the above, an example in which two layers of the first insulating material layer 92 and the second insulating material layer 93 are combined has been described, but in the present invention, three or more insulating material layers are combined. Also good.
In this case, for example, on the upper side of the first insulating material layer 92, the second insulating material is used for the combination of the first insulating material layer 92 and the second insulating material layer 93. There is an insulating material layer similar to the above or an arbitrary layer having other functions and characteristics below the material layer 93 or between the first insulating material layer 92 and the second insulating material layer 93. Also good.

In this case, the insulating material layer to be added may have any conditions such as its pore diameter, porosity, and thickness.
Although it does not specifically limit as the workpiece | work 10, In this embodiment, what is used as a board | substrate of an electronic device is mentioned, for example. Specific materials include, for example, various types of glass such as quartz glass, alkali-free glass and quartz, various ceramics such as alumina, silica and titania, various semiconductor materials such as silicon and gallium-arsenic, polyethylene, polypropylene, polystyrene and polycarbonate. , Polyethylene terephthalate, polytetrafluoroethylene, polyimide, liquid crystal polymer, phenol resin, epoxy resin, acrylic resin, and other dielectric materials such as plastics (resin materials). Among these, it is particularly preferably used for various glasses such as quartz and quartz and various semiconductor materials. Further, even a substrate in which a semiconductor element, wiring, or the like is formed on the above-described base material can be processed.
Examples of the shape of the workpiece 10 include a plate-like shape and a long layer-like shape.

(2) Operation Method of Plasma Processing Apparatus Next, the operation (operation) of the plasma processing apparatus 1 will be described.
The workpiece 10 is disposed opposite to the plasma ejection part 5. The power supply circuit 7 is activated and the valve 83 is opened. Then, the gas flow rate is adjusted by the mass flow controller 82, and the gas is sent out from the gas cylinder 81. Thereby, the gas sent out from the gas cylinder 81 flows through the processing gas pipe 84 and is supplied to the processing gas inlet 6 at a predetermined flow rate. Then, the processing gas introduced between the dielectric parts 4 (processing gas flow path) from the processing gas introduction port 6 flows downward and reaches between the first electrode 2 and the second electrode 3.

On the other hand, by the operation of the power supply circuit 7, a high frequency voltage is applied between the first electrode 2 and the second electrode 3, and an electric field is generated in the plasma generation region 30.
The processing gas that has flowed into the plasma generation region 30 is activated by discharge to generate plasma.
At this time, the plasma generated between the first electrode 2 and the second electrode 3 comes into contact with the dielectric portion 4 existing in the plasma generation region 30. And the foreign material 40 derived from the material which comprises the dielectric material part 4 is produced | generated by the contact.

The foreign matter 40 flows downward along the processing gas flow path together with the processing gas, and reaches the foreign matter capturing portion 9 which is the plasma ejection portion 5. Then, the processing gas passes through the insulating material layer 91 of the foreign material capturing unit 9.
At this time, the foreign material 40 contained in the processing gas cannot pass through the hole of the insulating material layer 91 and is captured by the insulating material layer 91. On the other hand, the processing gas passes through the holes of the insulating material layer 91.
The processing gas that has passed through the insulating material layer 91 is ejected from the foreign matter capturing part 9 (plasma ejecting part 5) toward the surface to be treated of the workpiece 10. Then, the processing gas ejected from the foreign matter capturing unit 9 is subjected to plasma processing (etching, film formation, etc.).

Such a plasma processing apparatus 1 moves relatively with respect to the workpiece 10 disposed to face the foreign substance capturing unit 9. That is, the plasma processing apparatus 1 performs plasma processing at a desired position on the workpiece 10 while moving in the x-axis direction, the y-axis direction, or to a specific position by a moving unit (not shown).
For example, after the plasma processing apparatus 1 is scanned in the positive y-axis direction of the processing target surface 101 of the workpiece 10 while ejecting plasma while the workpiece 10 is fixed, a predetermined pitch (for example, the plasma ejection portion 5 Move in the x-axis direction and scan in the y-axis minus direction. Such scanning (movement) can be sequentially repeated to process the entire surface 101 of the workpiece 10.

Conversely, the workpiece 10 can also move relative to the plasma processing apparatus 1.
For example, the entire processing target surface 101 of the workpiece 10 may be processed by moving the workpiece 10 in the plus direction of the x-axis while the plasma processing apparatus 1 is fixed. In this case, the plasma processing apparatus 1 uses electrodes (first electrode 2 and second electrode) that are longer than the length (width) in the direction orthogonal to the traveling direction of the workpiece 10, so-called line-shaped electrodes. It is preferable to use it.

Moreover, when moving to a certain specific position and performing a plasma treatment in spot, the shape of the plasma ejection part 5 may be circular. That is, the size, shape, and the like of the plasma ejection portion 5 can be freely set and selected according to the size and shape of the processing target surface 101, the processing efficiency, the processing purpose, and the like.
By such an operation, the entire surface or a part of the processing surface 101 can be easily plasma-treated under atmospheric pressure without damaging or contaminating the processing surface 101 of the workpiece 10.

The plasma processing apparatus 1 described above can be applied to processing and removal of an oxide insulating film, non-strain processing such as glass (quartz), crystal processing, and the like. Moreover, application to MEMS etc. is also possible.
As mentioned above, although the plasma processing apparatus of this invention was demonstrated based on embodiment of illustration, this invention is not limited to these. Each unit constituting the plasma processing apparatus can be replaced with any component that can exhibit the same function. Moreover, arbitrary components may be added.

Moreover, the foreign material capture | acquisition part should just be formed in the plasma ejection part, without covering a plasma ejection part.
Even if the foreign matter trapping part is not formed in the plasma ejection part, it may be formed in any position where the processing gas flows between the plasma generation region and the surface to be processed of the workpiece, that is, in the vicinity of the plasma ejection part. That's fine.
Further, the mesh member 96 is not necessarily provided.
Moreover, the moving means for moving the second electrode is not particularly limited, and examples thereof include various moving mechanisms.

It is a longitudinal cross-sectional view which shows schematic structure of 1st Embodiment of the plasma processing apparatus of this invention. It is a longitudinal cross-sectional view which shows the other structural example of the foreign material capture part of the plasma processing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Plasma processing apparatus 2 ... 1st electrode 3 ... 2nd electrode 4 ... Dielectric part 5 ... Plasma ejection part 6 ... Process gas inlet 7 ... Power supply circuit 71 ... Conductor 72 ... ... Power supply 8 ... Gas supply means 81 ... Gas cylinder 82 ... Mass flow controller 83 ... Valve 84 ... Processing gas pipe 9 ... Foreign material trap 91 ... Insulating material layer 92 ... First insulating material layer 93 …… Second insulating material layer 95 …… Supporting member 96 …… Reticulated member 10 …… Workpiece 101 …… Surface to be treated 30 …… Plasma generation region 40 …… Foreign matter h ₁ …… Distance between electrode and workpiece h ₂ …… Distance between the foreign matter catching part and the workpiece

Claims (13)

A pair of opposing electrodes movable relative to the workpiece;
A power supply circuit comprising a power supply for applying a voltage between the pair of electrodes;
Gas supply means for supplying a processing gas for generating the plasma between the pair of electrodes;
A plasma ejection part that ejects the plasma toward the surface to be processed of the workpiece,
By applying the voltage while supplying the processing gas between the pair of electrodes, the processing gas is activated to generate plasma, and the surface to be processed of the workpiece is processed by the plasma. A plasma processing apparatus configured as follows:
A plasma processing apparatus comprising a foreign matter trapping portion made of a porous insulating material for trapping foreign matter generated by generation of the plasma at or near the plasma jetting portion.   The plasma processing apparatus according to claim 1, wherein the pair of electrodes are arranged along a direction orthogonal to the workpiece.   3. The plasma processing apparatus according to claim 1, wherein the foreign substance capturing unit is configured by a laminate in which the insulating material is laminated as two or more insulating material layers.   4. The plasma processing apparatus according to claim 3, wherein the foreign substance capturing unit is configured such that the insulating material is made of a different kind of material in each of the insulating material layers.   The plasma processing apparatus according to claim 1, wherein the insulating material is made of ceramics.   The plasma processing apparatus according to any one of claims 3 to 5, wherein the foreign matter trapping portion has a different pore diameter in each insulating material layer.   The foreign matter trapping part is composed of one or more of the insulating material layers and the one insulating material layer positioned on the pair of electrodes from among the insulating material layers. The plasma processing apparatus according to claim 3, wherein the plasma processing apparatus includes at least one set of the insulating material layers whose hole diameter is smaller than the latter hole diameter.   The foreign matter trapping part is composed of one or more of the insulating material layers and the one insulating material layer positioned on the pair of electrodes from among the insulating material layers. The plasma processing apparatus according to claim 3, wherein the plasma processing apparatus includes at least one set of the insulating material layers whose porosity is smaller than the latter porosity.   The plasma processing apparatus according to claim 1, wherein the porous body has a pore diameter of 200 μm or less.   The plasma processing apparatus according to claim 1, wherein the porosity of the porous material is 30 to 85%.   11. The plasma processing apparatus according to claim 1, wherein each of the pair of electrodes is covered with a dielectric portion on a surface facing at least one of the electrodes. A pair of electrodes facing each other;
A power supply circuit comprising a power supply for applying a voltage between the pair of electrodes;
Gas supply means for supplying a processing gas for generating the plasma between the pair of electrodes;
A plasma ejection part for ejecting the plasma toward the surface of the workpiece;
A plasma processing apparatus comprising a foreign matter trapping portion made of a porous insulating material that traps foreign matter generated by the generation of the plasma at or near the plasma ejection portion,
A surface that activates the processing gas to generate plasma by supplying the processing gas while supplying the processing gas between the pair of electrodes, and processes the surface to be processed of the workpiece by the plasma A processing method,
A surface treatment method characterized in that the foreign matter generated by the generation of the plasma is caught by the foreign matter catching portion, and the surface to be treated of the workpiece is treated by the plasma after passing through the foreign matter catching portion.   The surface treatment method of Claim 12 which processes the said to-be-processed surface of the said workpiece | work, moving relatively the said workpiece | work and the said plasma processing apparatus.

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