JP2979308B1 - Flat plate type plasma processing equipment - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To effectively and chemically utilize a neutrally excited species which is chemically active without causing damage by ions or electrons, and to reliably and efficiently reform a surface of an object to be treated, and to uniformly reform the entire surface. And so on. SOLUTION: A flat plate-shaped high-voltage electrode 1 and a ground electrode 6 using punched metal are arranged to face each other with an insulator 5 interposed therebetween to form a discharge portion 4 formed by a minute gap between the electrodes 1 and 6. By supplying the mixed reaction gas to the portion 4 from a plurality of locations around the electrodes 1 and 6 through the slit-shaped gas supply holes 18A and 18B in a counter-current state, the mixed reaction gas is supplied to both electrodes 1 and 6. Is excited and decomposed by a glow discharge plasma generated by the application of a high-frequency voltage to generate a gas flow containing a chemically active neutral excited species. Are configured to irradiate the surface of the object to be treated, which is disposed to face the outside of the discharge unit 4, through the gas flow ejection holes 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat plate type plasma processing apparatus, and more particularly, to an inert gas generated by a glow discharge plasma generated in a discharge portion when a high frequency voltage is applied to a pair of flat electrodes. And a reactive gas containing oxygen or a fluorine-containing compound (fluorocarbon-based) gas is decomposed to generate a gas flow containing a chemically active neutral excited species. When a paint is applied to a water-repellent resin such as polypropylene or PTFE (polytetrafluoroethylene) or when printing with an aqueous ink, the surface is modified to be hydrophilic to improve wettability, Ceramics,
The present invention relates to a flat plate type plasma processing apparatus used for performing various surface treatments such as hydrophilizing a hydrophobic surface of a metal, a semiconductor, or the like, and washing and removing an organic substance attached to the surface.

[0002]

2. Description of the Related Art As a plasma processing apparatus generally used for surface treatment such as surface modification and organic substance cleaning as described above, most of the conventionally known plasma processing apparatuses are disclosed, for example, in Japanese Patent Application Laid-Open No. H5-25-2.
As disclosed in Japanese Patent No. 35541 and Japanese Patent Application Laid-Open No. 6-119995, a discharge portion between a flat high-voltage electrode and a ground electrode arranged in a container at a predetermined interval so as to face each other. A low-pressure glow discharge plasma is generated by applying a high-frequency voltage to both electrodes by introducing a discharge reaction gas such as oxygen, and both electrodes are generated by a gas containing a chemically active neutral excited species generated by the plasma. while,
Specifically, it is configured to perform a surface treatment such as modifying the surface of an object to be processed which is installed and held on a ground electrode.

[0003]

By the way, in a discharge plasma and a gas flow generated and diffused by the plasma, a chemically active neutral gas which is most effective for the surface treatment such as the modification of the surface of an object to be treated. In addition to the excited species (particles), ions and electrons are included. Although these ions and electrons are also effective for surface treatment such as reforming, they are most contained in plasma as in a conventional plasma processing apparatus in which an object is placed between both electrodes to perform surface treatment. In the case where ions, electrons, and the like are directly exposed to the surface of the object to be processed, the accompanying damage is greater. In other words, when ions or electrons are directly exposed to the surface of the object to be processed, or when irradiation is locally concentrated, the surface of the object to be processed is unnecessarily etched or electric charges stay on the surface, and the There is a problem that the physical properties of the object to be processed are easily destroyed, for example, the surface of the object to be processed is damaged by the creeping discharge of the accumulated charges, and a negative effect more than a surface treatment effect such as modification by ions or electrons is caused. .

On the other hand, an object to be processed is arranged at a sufficiently distant position not to be directly exposed to the plasma, and a gas flow containing a chemically active neutral excited species generated in the plasma generation section is separated from the generation position. Conventionally, an indirect plasma processing apparatus has been proposed in which an object to be processed is guided to a position, and is ejected to a surface to perform processing. In this indirect plasma processing apparatus,
Although the ions and electrons do not cause damage as described above, the chemically activated neutral excited species that is most effective for surface treatment in the generated gas flow reaches the end of its life while being guided to the object to be treated. The activity required for processing is impaired, and as a result,
There are problems that the surface treatment becomes impossible or the treatment efficiency is greatly reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and utilizes a chemically active neutral excited species as effectively as possible without causing damage by ions or electrons. It is an object of the present invention to provide a flat plate type plasma processing apparatus capable of reliably and efficiently reforming and cleaning the entire surface uniformly.

[0006]

In order to achieve the above object, a plasma processing apparatus according to the present invention comprises a plate-like high voltage electrode and a plate-like ground electrode having a large number of gas flow ejection holes all over its surface. with discharge portions consisting of a small gap between opposed to the electrodes sandwiching the insulator is formed, the small gap between the electrodes serving as the discharge unit, at least helium,
Condition to be counter-flow from the plurality of positions of the electrodes around the mixed reaction gas at atmospheric pressure or near atmospheric pressure the pressure with a reactive gas containing an inert gas and oxygen or a fluorine-containing compound Monoga scan include hydrogen or argon A mixed reactant gas supply means supplied by
Gas stream containing chemically active neutral excited species to decompose the mixed reaction gas by generating a glow discharge plasma over the entire area of and means for generating in said small clearance, the minute gap the generated chemically gas stream containing active neutral excited species is ejected from <br/> plurality of gas injection holes formed in the ground electrode entirely within, faces the outside of the discharge portion It is characterized in that it is configured to irradiate the surface of an object to be disposed .

According to the present invention having the above-described structure, a chemically active gas generated by the generation of glow discharge plasma in a discharge portion in which a flat high-voltage electrode and a ground electrode are opposed to each other with a small gap therebetween is provided. A large number of gas flow outlets formed on the entire surface of the ground electrode with a gas flow containing neutral excited species, ions, and electrons
Damage caused by direct exposure of the surface of the workpiece to ions, electrons, etc. contained in the plasma by irradiating the surface of the workpiece facing the outside of the discharge unit with more jets Irradiating the surface of the object to be treated with the most effective neutral excited species for the surface treatment before its activity is impaired, while suppressing the occurrence of neutrons sufficiently. In addition, the mixed reaction gas is supplied in a counter-current state from a plurality of locations around the electrode, and the pressure distribution in the minute gap serving as the discharge portion is made substantially uniform, so that a substantially uniform plasma is stably generated over the entire area of the discharge portion. As a result, a gas stream containing a chemically active neutral excited species can be generated throughout the discharge section.

As described above, the surface of an object to be treated is irradiated with a highly active neutral excited species while suppressing damage caused by ions, electrons, and the like, and glow discharge plasma is applied over the entire discharge portion under atmospheric pressure. By synergistic with the ability to generate a gas flow containing a substantially homogeneous neutral excited species from the whole area of the discharge part by generating with good stability, a predetermined surface treatment such as reforming is ensured, with high quality, and It can be performed efficiently.

In the flat plate type plasma processing apparatus which operates as described above, the two electrodes are formed in a disk shape, and the mixed reaction gas supply means is provided in the disk- shaped electrode.
The outer peripheral portion along a plurality of circumferential plurality of positions of the slit-shaped gas supplying hole and disc-shaped electrode central mixing reactive gases jetted toward the center along a plurality of circumferential locations of the pole peripheral portion in the radial direction in the radial direction And a plurality of slit-shaped gas supply holes for ejecting the mixed reaction gas toward the discharge portion, the uniformity of the pressure distribution of the mixed reaction gas in the minute gap serving as the discharge portion is further improved, and the entire area of the discharge portion is It is possible to generate plasma more uniformly over a range.

The ground electrode in the flat plate type plasma processing apparatus having the above-mentioned configuration may be configured as follows.
It is most preferable to use punched metal, specifically, a metal plate material with excellent heat resistance and rigidity such as stainless steel and aluminum that has been subjected to punching processing, from the viewpoint of manufacturing and durability, but other than that A copper plate subjected to a punching process may be used.

Further, in the flat-plate type plasma processing apparatus having the above-mentioned structure, a reaction gas supply passage connected to the mixed reaction gas supply means and a cooling water jacket are provided inside the high-pressure electrode. By adopting the configuration, while making the entire electrode section simple and thin,
By preventing overheating of the electrode during continuous surface treatment for a long time, it is possible to improve the efficiency of the predetermined surface treatment and the durability of the entire apparatus.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a semi-longitudinal front view showing an embodiment of a flat plate type atmospheric pressure plasma processing apparatus according to the present invention, FIG. 2 is a half cross-sectional bottom view thereof, and FIG.

The flat plate type atmospheric pressure plasma processing apparatus 20 according to this embodiment includes a high pressure electrode 1 formed in a circular flat plate shape.
A large number of gas flow ejection holes 3 are punched on the entire surface in the form of a circular flat plate, and a high pressure electrode is sandwiched between the high voltage electrode 1 and a thin annular insulator 5 so as to form a discharge portion 4 having a minute gap. A ground electrode 6 such as a stainless steel punched metal disposed opposite to the electrode 1, and a thin wall having an outer diameter equal to the outer diameter of the high-voltage electrode 1 and having a minute gap serving as a discharge part 4 on the inner side. An annular outer gas ring 2 made of an insulating material fixed in a concentric manner to one surface of the high-voltage electrode 1 having an annular portion 2a formed in a paragraph shape.
A fixing jig 7 for fixing the ground electrode 6 to the high-voltage electrode 1 via an inner gas ring 12 made of an insulating material at the center thereof; and an outer peripheral surface of the high-voltage electrode 1 excluding the discharge section 4 and an annular gas. A cylindrical insulator 8 arranged on the outer peripheral surface of the ring 2, an insulator 9 in contact with the other surface of the high-voltage electrode 1, and aluminum surrounding the entirety of the cylindrical insulator 8 and the insulator 9 Cover casing 10 made of
And

An inner end portion 11a of an annular plate portion 11 made of aluminum or the like fixed to one end of the cover casing 10 and covering the surface of the annular outer gas ring 2 is made thinner than the annular outer gas ring 2. Bent to the annular part 2a side,
The outer peripheral portion of the ground electrode 6 such as a punched metal is pressed against the thin annular portion 2a at the edge thereof, thereby fixing the outer peripheral portion of the ground electrode 6 and grounding by the annular plate portion 11 and the cover casing 10. The electrode 6 is electrically isolated from the high-voltage electrode 1 and grounded.

In the solid inside of the high-voltage electrode 1, one end is opened on a surface different from the side on which the discharge portion 4 is formed, and the other end is formed in the outer gas ring 2 and the inner gas ring 12, respectively. some of the annular groove 13 and 14 to become is opened connected, few are supplied at atmospheric pressure from one opening
At least a reaction gas supply passage for introducing a mixed reaction gas of an inert gas containing helium, hydrogen or argon and a reactive gas containing oxygen or a fluorine-containing compound (fluorocarbon) gas into the annular grooves 13 and 14. Cooling water jackets 17 are incorporated in the solid portions at positions avoiding the reaction gas supply passages 15 and 16, respectively.

As shown in FIG. 3, at a plurality of locations at equal intervals in the circumferential direction of the annular outer gas ring 2,
A plurality of slit-like gases that connect the annular groove 13 and the minute gap to be the discharge part 4 and eject the mixed reaction gas from the outer periphery of the minute gap toward the center along the radial direction as shown by an arrow a in FIG. A plurality of supply holes 18 </ b> A are formed, and the annular groove 14 is provided at a plurality of equally spaced positions in the circumferential direction of the inner gas ring 12 fixed to the center of the high-voltage electrode 1 by the fixing jig 7. And a plurality of slit-shaped gas supply holes 18B for ejecting the mixed reaction gas from the center of the minute gap toward the outer periphery along the radial direction as shown by arrow b in FIG. Are formed, and the mixed reaction gas is supplied to the minute gap from the slit-shaped gas supply holes 18A and 18B in a state of counterflow between the inside and the outside.

Next, the mode of use and operation of the flat-plate type atmospheric pressure plasma processing apparatus 20 configured as described above will be described. In a state in which a resin sheet material 19 such as PTFE, which is an example of an object to be treated, is disposed to face the outside of the discharge unit 4, the above-described reaction gas supply passage 15 is placed under atmospheric pressure or a pressure close to atmospheric pressure (weakly reduced or weakly pressurized). , 16 are supplied to the annular grooves 13, 14 via the supply passages 15, 16, and then through the plurality of slit-shaped gas supply holes 18 A, 18 B in the circumferential direction. As described above, the current is supplied to the discharge portion 4 composed of a minute gap formed between the high-voltage electrode 1 and the ground electrode 6 in a state of counterflow between the inside and the outside, and a substantially equal pressure distribution is obtained over the entire area of the discharge portion 4. .

As described above, by applying the high-frequency voltage (10 KHz to 500 MHz) to the high-voltage electrode 1 under the condition that the pressure distribution of the mixed reactant gas in the minute gap is substantially equal, the entire discharge unit 4 is covered. The glow discharge plasma can be generated uniformly and stably, and the mixed reaction gas in the discharge part 4 can be efficiently excited and decomposed by the stable glow discharge plasma to generate ions, electrons and chemically active gas. By generating a homogeneous reactive gas flow containing the sexually excited species, the gas flow is ejected from a large number of ejection holes 3 formed in the ground electrode 6 to irradiate the surface of the resin sheet material 19, The surface of the resin sheet material 19 is appropriately modified by modifying the surface of the resin sheet material 19 to be hydrophilic so as to remarkably improve the degree of adhesion of paint and ink to the resin sheet material 19 and the adhesiveness. It is possible to make.

Here, the resin sheet material 19, which is an example of an object to be processed, is installed facing the outside of the discharge unit 4, so that ions and electrons contained in the plasma are removed from the resin sheet material 1.
The damage caused by the direct irradiation of the surface of the resin sheet 9 is extremely small, and the physical properties of the resin sheet material 19 are not destroyed. It is possible to irradiate the entire surface of the resin sheet 19 before this, and to perform the predetermined surface treatment reliably, effectively and efficiently.

In particular, since the reaction gas supply passages 15 and 16 and the cooling water jacket 17 are incorporated in the solid inside of the high-pressure electrode 1, the configuration of the electrode section is simple and thin, the production cost is reduced, and the apparatus is compact. It is possible to prevent overheating of the high-voltage electrode 1 when performing the surface treatment for a long time while improving the efficiency by continuous treatment.

It should be noted that a configuration in which a matching device for matching the high-frequency power supply (not shown) and the high-voltage electrode 1 is integrally incorporated in the upper portion of the cover casing 10 described in the above embodiment may be adopted. In this case, the matching unit and the electrode 1 can be directly attached both electrically and physically. Particularly, in a high-frequency (100 KHz or more) high-power use mode, the power loss is reduced, and the efficiency of plasma processing is improved. In addition to stabilization, it is possible to prevent the occurrence of troubles such as catching with other objects and radio wave leakage due to the connection wiring between both being exposed to the outside, and to further reduce the size of the entire device. .

In the above embodiment, the electrodes 1 and 6 are formed in a disk shape. However, the electrodes 1 and 6 may be formed in a rectangular plate shape. Alternatively, the mixed reaction gas may be ejected to form a counter flow.

[0023]

As described above, according to the present invention, a chemically active neutral excited species generated by the generation of a glow discharge plasma in a discharge portion in which a high-voltage electrode and a ground electrode are arranged to face each other. Since a predetermined surface treatment is performed by irradiating a gas flow containing ions, electrons, and the like on the surface of the object to be treated, which is disposed to face the outside of the discharge part, ions, electrons, etc. contained in the plasma It is possible to irradiate the surface of the object to be treated with the most effective neutral excited species for surface treatment without impairing its activity, while sufficiently suppressing the damage caused by direct exposure of the surface of the object to be treated. What is possible is that the mixed reactant gas is supplied to the discharge portion in a counter-current state from a plurality of locations around the electrode, and the glow discharge plasma is generated almost uniformly and stably over the entire area of the discharge portion. Including sexually excited species By synergy with being able to efficiently generate a gas flow in the entire region of the discharge portion, there is an effect that the object surface to be treated reliably and entirely homogeneous, yet it is possible to efficiently modify and cleaning process.

Further, by adopting the configuration as described in claim 2, the uniformity of the pressure distribution of the mixed reactant gas in the minute gap to be the discharge part is further enhanced, and the plasma generation over the entire area of the discharge part In addition, the generation of the gas flow can be made more uniform and homogenized to improve the quality of the surface treatment. In addition, by adopting the configuration as set forth in claim 4, in addition to the above-mentioned effects, in addition to the above-mentioned effects, it is possible to improve the surface treatment for a long time. Thus, overheating of the high-voltage electrode during the surface treatment can be prevented, and the predetermined surface treatment can be continuously and efficiently performed.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of a flat plate type atmospheric pressure plasma processing apparatus according to the present invention.

FIG. 2 is a half cross-sectional bottom view of the flat plate type atmospheric pressure plasma processing apparatus.

FIG. 3 is an enlarged vertical sectional front view of a main part of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 high voltage electrode 3 gas flow ejection hole 4 discharge part (micro gap) 5 insulator 6 ground electrode (punched metal) 15, 16 reaction gas supply passage 17 cooling water jacket 18A, 18B slit gas supply hole 19 resin sheet material (coated Example of processed material)

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 21/3065 H01L 21/302 B (56) References JP-A 62-40829 (JP, U) (58) Fields surveyed ( Int.Cl. ⁶ , DB name) B01J 19/08 C23F 1/08 C23G 5/00 H01L 21/302-21/3065 H05H 1/46

Claims (4)

(57) [Claims] A flat high voltage electrode and a flat ground electrode having a large number of gas flow ejection holes all over the plate are opposed to each other with an insulator interposed therebetween to form a discharge portion having a minute gap between the two electrodes. And at least a small gap between the two electrodes serving as the discharge part.
Potassium, a counter flow from a plurality of locations around the electrode mixture reaction gas at atmospheric pressure or near atmospheric pressure the pressure with a reactive gas containing an inert gas and oxygen or a fluorine-containing compound Monoga scan include hydrogen or argon A mixed reaction gas supply means for supplying a high-frequency voltage to both of the electrodes, and
The gas stream containing chemically active neutral excited species to decompose the mixed reaction gas by generating a glow discharge plasma and means for generating within said minute gap Te, generated in the small gap The gas flow containing the chemically active neutral excited species is ejected from a large number of gas flow ejection holes formed on the entire surface of the ground electrode, and an object to be processed disposed opposite to the outside of the discharge unit is discharged. A flat plate type plasma processing apparatus characterized in that it is configured to irradiate a surface. 2. A method according to claim 1, wherein said two electrodes are disc-shaped, and said mixed-reaction-gas supply means jets the mixed reaction gas from a plurality of circumferential locations of the outer periphery of the disc- shaped electrode toward a center along a radial direction. And a plurality of slit-shaped gas supply holes for jetting a mixed reaction gas radially from a plurality of circumferential locations at the center of the disc- shaped electrode toward the outer peripheral portion. 4. The flat plate type plasma processing apparatus according to 1. 3. The flat plate type plasma processing apparatus according to claim 1, wherein the ground electrode is made of punched metal. 4. The flat plate type plasma processing according to claim 1, wherein a reaction gas supply passage connected to the mixed reaction gas supply means and a cooling water jacket are provided inside the high pressure electrode. apparatus.