JP2002008893A - Plasma machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma machining method easy to make the droplet capturing (depositing) and removing operations, capable of preventing droplet inclusion in the plasma machining part, and capable of making stable surface treatment of a base material (work to be treated). SOLUTION: Plasma is generated by performing vacuum arc discharge in a vacuum atmosphere into which a reactive gas is introduced if necessary, and the plasma is allowed to flow into the plasma machining part T, and the work 30 placed there T is subjected to a surface treatment process with plasma. The plasma flow P from the plasma generation part E is bent in the direction not confronting the plasma generation part and allowed to flow into the plasma processing part T, and the position confronting the plasma generation part E is made a droplet capturing part D to capture cathode material in the form of particulates (droplets) as biproduct from the cathode when plasma is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing method suitable for performing a surface treatment such as thin film formation or surface modification using plasma generated by vacuum arc discharge.

[0002] Here, the plasma processing method is to deposit particles containing ions generated by discharge plasma on the surface of a workpiece (also referred to as a material to be processed, further, a substrate or a substrate). Forming a film, performing surface modification such as surface hardening or structural change by injecting into the substrate surface, etching the substrate, and further combining them simultaneously or sequentially Or surface treatment.

[0003]

2. Description of the Related Art By forming a thin film on a surface of a solid material in a plasma, by implanting ions, or by etching, the surface characteristics of the solid can be improved or a new function can be added to the solid surface. It is known that you can. In particular, films formed using plasma containing metal ions can be used to enhance wear resistance and corrosion resistance on solid surfaces, optical thin films,
It is useful as a transparent conductive film.

As a technique for generating plasma containing metal ions, there is a vacuum arc plasma method. Vacuum arc plasma is an arc discharge between a cathode and an anode, in which a cathode material evaporates from a cathode spot formed on a cathode surface to form a plasma by a cathode evaporation material. In addition, a reactive gas or an inert gas (rare gas) is used as an atmosphere gas.
Alternatively, when both are introduced at the same time, the reactive gas and the inert gas are simultaneously ionized. Using such plasma, surface treatment can be performed by forming a thin film on a solid surface, implanting ions, or performing these processes simultaneously or sequentially.

In general, in vacuum arc discharge, metal ions (ions of the cathode material) are emitted from the cathode spot, and at the same time, from submicron to several hundred microns (0.1 to 10 μm).
(Μm) is emitted. These fine particles are generally called droplets. When droplets are generated and adhere to the surface of the substrate, the uniformity of the surface of the substrate is lost, and a desired surface treatment on the substrate, that is, a desired property improvement or functionalization cannot be performed.

As one method of solving the droplet problem, a magnetic filter method (PJ Martin, RPNetterfield
and TJKinder, Thin Solid Firms 193/194 (1990) 77)
There is. In the magnetic filter method, a vacuum arc plasma is transported to a processing section through a curved droplet collecting duct. That is, since the droplet collection duct is curved, the generated droplet (small droplet) is a molten / liquefied material (liquid material), and thus is attached and captured (collected) on the inner peripheral wall of the duct. At the outlet of the duct, plasma containing almost no droplets is obtained. In addition, a magnet is arranged along the duct to bend the plasma flow by a magnetic field, so that the plasma is efficiently moved (transported) to the plasma processing unit.

As another method, a method has been proposed in which a shield plate (protective body) is provided between a cathode and a base material (workpiece) to prevent droplets from adhering to the base material. (JP-A-10-25565). This technique is called a shield method.

[0008]

However, the magnetic filter method and the shield method for solving the problem of the droplet have the following problems, respectively.

[0009] Since the droplets accumulate on the inner wall of the curved duct, it is necessary to remove them regularly. However, the operation is not easy because the duct is usually thin. Further, when deposited to a thickness of about 0.5 mm, the volume may be peeled off from the curved inner wall and mixed as impurities into the plasma. Further, when the droplet is not completely liquefied as in the case where a material containing graphite or carbon is used for the cathode, the droplet elastically collides with the inner wall of the curved duct, repeatedly reflects, and emerges from the duct outlet, It adheres to the surface of the workpiece.

[0010] The shield plate (protector) not only shields droplets but also shields ions generated from the cathode. As a result, the number of ions moved (arriving) to the surface of the substrate to be treated is reduced to 1/3 or less of that without the shield plate. Also, from the shield plate area,
When the surface of the base material to be treated is large, a portion that cannot be shielded by the shield plate is generated, and droplets adhere to the surface of the portion. Furthermore, in the case of solid droplets,
Since the droplets are irregularly reflected on the inner wall of the chamber (container), it is difficult to prevent the droplets (in a solid state) from adhering to the substrate by the shield plate.

In view of the above, the present invention makes it possible to easily collect (deposit) and remove droplets, prevent the droplets from being mixed into a plasma processing portion, and obtain a desired material for a substrate (workpiece). It is an object of the present invention to provide a plasma processing method and a plasma processing apparatus capable of stably performing surface treatment.

[0012]

DISCLOSURE OF THE INVENTION In order to obtain a plasma-processed portion in which droplets are not mixed, the present inventors provide a special droplet collecting portion for capturing (collecting) droplets and utilize magnetic field induction. The inventors have found that a plasma processing portion where droplets are not mixed can be formed at a position different from the droplet collecting space if the plasma flow is bent or diffused, and the inventors have arrived at a plasma processing method having the following configuration.

If necessary, vacuum arc discharge is performed in a vacuum atmosphere in which a reactive gas is introduced to generate plasma, and the plasma is caused to flow into a plasma processing portion, and an object to be processed arranged in the plasma processing portion is flowed. A method of performing surface treatment processing by using plasma, wherein a plasma flow from a plasma generation unit is bent or diffused in a direction not facing the plasma generation unit by magnetic field induction, flows into the plasma processing unit, and faces the plasma generation unit. Cathode material particles (hereinafter, referred to as “droplets”) by-produced from the cathode when plasma is generated at the position are collected.

In the present invention having the above structure, the flow of the droplet discharged from the cathode is a straight flow and is not affected by an external magnetic field, whereas the vacuum arc plasma itself is easily affected by the external magnetic field. This utilizes the effect of changing the flow direction (moving direction). That is, by providing a droplet collecting portion at a position facing the cathode and bending the plasma flow at another angle in the middle thereof,
The shape of the droplet collecting portion can be made into a form (such as removal) in which the collected droplets can be easily collected after being collected, and can be prevented from being separated and mixed into the plasma processing portion. Furthermore, from the characteristics of the droplet and the plasma with respect to the magnetic field, the magnetic field is used to conduct the plasma in a direction different from the moving direction of the droplet.
Then, a plasma processing portion is formed in a plasma region not including the droplet.

In the above configuration, the bending angle of the plasma flow is set to about 2 with respect to the plasma emission axis of the plasma generating section.
The angle is set to 0 to 95 °. If the emission axis and the magnetic field bending direction are too close, droplets may be mixed in the plasma flow toward the plasma processing portion.

As one of the above-mentioned embodiments, there is an embodiment in which a droplet collecting port is provided at a position facing the plasma generating portion, and the droplet is collected by a cylindrical body connected to the droplet collecting port. . In this case, it is easy to prevent the solid droplets from being mixed into the plasma flow due to irregular reflection.

As another one of the above embodiments, there is an embodiment in which a plasma flow is diffused and bent by a magnetic field so as to be directed to a donut-shaped plasma processing portion. In the case of this mode, the droplet collecting portion can be formed ahead of the center of the plasma processing portion, and the structure of the droplet collecting portion is simplified.

In each of the above plasma processing methods, N ₂ , O ₂ , H ₂ , CH ₄ , C ₂ H are usually used as reactive gases.
₂ , one or more selected from the group consisting of C ₂ H ₄ , C ₂ H ₆ , CO and CO ₂ , and the pressure of the vacuum atmosphere is 10 to 10 ⁻⁵ Pa.

The plasma processing apparatus that can embody the plasma processing method of the present invention has the following configuration.

The plasma processing apparatus includes a plasma generating section, a plasma processing section, and a droplet collecting section at a portion not interfering with the plasma processing section in a vacuum chamber, and controls a plasma flow from the plasma generating section. A plasma induction magnetic field generator for generating a magnetic field to bend or diffuse toward the plasma processing section.

As one mode of the above-mentioned plasma processing apparatus, the plasma processing section is at a position orthogonal to the plasma generating section.
A configuration may be adopted in which the droplet collecting units are respectively located at the facing positions.

In another embodiment, the intersection angle of the plasma guide section connecting the plasma generation section and the plasma processing section with the plasma emission axis of the plasma generation section is 20 to 80 °.
In addition, the droplet collecting portion may be formed of a tubular body whose tip is closed, and the tubular body may have a droplet collecting port at a position facing the plasma generating portion.

In still another embodiment, the plasma processing section is arranged in a donut shape, and a plasma induction magnetic field generator (plasma diffusion magnetic field generator) for diffusing the plasma so that the plasma flows toward the plasma processing section is disposed. The configuration may be such that the let collecting part is disposed inward of the donut-shaped plasma processing part.

As a more specific embodiment in the above embodiment,
A plasma diffusion magnetic field generator is arranged on the bottom side of the plasma processing section in the vacuum chamber, and a droplet collection section is formed by a tapered cylindrical body continuous to the peripheral wall of the vacuum chamber forming the plasma processing section. can do.

Similarly, as another specific mode, the droplet collecting portion is also used as a flat bottom wall of a vacuum chamber forming a plasma processing portion, and a plasma diffusion magnetic field is generated below the outside of the flat bottom wall. A container may be provided.

Further, in each of the above embodiments, the droplet collecting portion is provided with the droplet energy absorber for absorbing the kinetic energy of the droplet, so that the droplet is more reliably prevented from being mixed into the plasma due to irregular reflection. Can be prevented.

According to the plasma processing method and the plasma processing apparatus of the present invention, a large-volume plasma containing single or plural kinds of element ions, atoms and molecules and containing no droplet can be easily and inexpensively generated. It becomes possible.

In addition, it is possible to form a thin film and perform surface processing over a large area at low cost by using plasma.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. It should be noted that the present invention is not limited to the configuration shown in the drawings, and it goes without saying that various design changes are possible.

FIG. 1 is a schematic model diagram of a plasma processing apparatus used when the present invention is applied to a vacuum arc vapor deposition method which is one form of the plasma processing method.

In the plasma processing method (vacuum arc deposition method) of the present embodiment, basically, a plasma is generated by performing a vacuum arc discharge in a vacuum atmosphere into which a reactive gas is introduced if necessary. This is a method in which the workpiece is moved to a plasma processing unit, and a workpiece disposed in the plasma processing unit is subjected to surface processing using plasma.

The constituent particles of the plasma include not only the evaporating substance from the cathode 12 or the charged particles (ions, electrons) which have been turned into plasma from the evaporating substance and the introduced gas, but also the molecules in the pre-plasma state. , Including neutral particles of atoms.

In the vacuum arc deposition method, the deposition conditions are as follows:
Current: 1 to 600 A (preferably 5 to 500 A, more preferably 10 to 150 A), Voltage: 5 to 100 V (preferably 10 to 80 V, more preferably 10 to 50 V)
V), pressure: ^{10-5 to} 10 Pa (preferably ^{10-4 to} 5)
Pa, more preferably 10 ^{-2 to 1} Pa).

The plasma processing apparatus shown in FIG. 1 basically has an arc generating section E, a droplet collecting section D and a plasma processing section (process section) formed in a vacuum chamber 10.
This is a configuration including T.

The vacuum arc generator E is provided with a cathode (cathode)
12, a cathode protector 13, an anode (anode) 14, a trigger electrode 16, and an arc stabilizing magnetic field generator (magnet) 18.

The cathode 12 is a source for supplying a main component of plasma, and the material for forming the cathode 12 is not particularly limited as long as it is a solid having conductivity. Metal simple substance, alloy, inorganic simple substance,
Inorganic compounds (metal oxides / nitrides) and the like can be used singly or as a mixture of two or more, regardless of the particulars.

As the metal simple substance, Al, Ti, Zn, C
r, Sb, Ag, Au, Zr, Cu, Fe, Mo, W,
Nb, Ni, Mg, Cd, Sn, V, Co, Y, Hf,
Pd, Rh, Pt, Ta, Hg, Nd, Pb, etc. are used as alloys (metal compounds) as TiAl, AlSi, NdF.
e, inorganic simple substances such as C, Si, etc., and inorganic compounds (ceramics) such as TiO ₂ , ZnO, SnO ₂ ,
Examples include ITO (Indium Tin Oxide: indium oxide mixed with tin), oxides such as In ₂ O ₃ , Cd ₂ SnO ₄ , and CuO, and carbon / nitrides such as TiN, TiAlC, TiC, CrN, and TiCN. .

The cathode protector 13 covers the portion other than the surface of the cathode to be evaporated by electrically insulating and prevents the vacuum arc plasma generated between the cathode 12 and the anode 14 from being diffused backward. It is. General-purpose heat-resistant ceramics can be used. In the case where an electric insulating layer (simply a gap or a ceramic or a fluororesin is interposed) is formed between the cathode 12 and the cathode 12, a general-purpose stainless steel, aluminum alloy, or the like can be used.

If the cathode protector 13 is made of a heat-resistant ferromagnetic material such as iron or ferrite instead of stainless steel in the above case, the voltage applied from the plasma stabilizing magnetic field generator 18 disposed outside the vacuum chamber 10 can be increased. The generated magnetic field also magnetizes the cathode protector 13 itself and acts directly on the plasma, thereby facilitating the adjustment of the generated plasma distribution.

The material for forming the anode 14 is not particularly limited as long as it is a non-magnetic material which does not evaporate even at the temperature of the plasma and has conductivity. Regardless of a metal simple substance, an alloy, an inorganic simple substance, an inorganic compound (metal oxide / nitride), etc., they can be used alone or in combination of two or more. The material used for the above-described cathode can be appropriately selected and used. In the apparatus of the present embodiment, it is desirable to use stainless steel or copper and have a water-cooled structure.

The shape of the anode 14 is not particularly limited as long as it does not block the progress of the arc plasma. In the illustrated example, it is a cylindrical body (irrespective of a cylinder or a rectangular tube), but it may be formed in a coil shape, a U-shape, or a pair of upper, lower, left and right parallel.

The trigger electrode 16 is an electrode for inducing a vacuum arc between the cathode 12 and the anode 14. That is, by temporarily bringing the trigger electrode 16 into contact with the surface of the cathode 12 and then separating the trigger electrode 16, an electric spark is generated between the cathode 12 and the trigger electrode 16. When the electric spark is generated, the electric resistance between the cathode 12 and the anode 14 decreases, and a vacuum arc is generated between the cathode and the anode.
As a material for forming the trigger electrode 16, general-purpose Mo (melting point: 2610 ° C.) or W (melting point: 3387 ° C.), which is a high melting point metal, is used.

The arc stabilizing magnetic field generator 18 is arranged on the outer periphery of the vacuum chamber 10 in the plasma generating section E,
This is for stabilizing the cathode point of the vacuum arc and the plasma generated by the arc discharge. That is, the magnetic field generator 18 is composed of a pair of ring-shaped magnets 18 in which the applied magnetic field to the plasma is cusp-shaped (in opposite directions).
a and 18b. The cusp-shaped applied magnetic field controls the movement of the arc cathode spot, and diffuses the plasma in the radiation direction (ie, flat columnar shape) to secure a current path between the cathode and anode and stabilize the arc discharge. . In addition, as this magnetic field generator 18, usually,
Use electromagnets (electromagnetic coils) or permanent magnets.

The cathode 12, the anode 14, and the trigger electrode 16 are connected to an external arc power supply 22 via the insulating introduction terminal 20, respectively. As the arc power supply 22, a general-purpose DC, pulse or DC superimposed pulse power supply is used. Note that, between the trigger electrode 16 and the arc power supply 22, the current flowing through the trigger electrode 16 is usually limited (adjusted).
To insert a limiting resistor (1 to 10Ω) 23 for performing the operation.

In some cases, gas is not introduced into the plasma processing section (processing section) T, but a gas introduction system 24 and a gas exhaust system 26 are connected. As these systems, general-purpose systems can be used. It is assumed that the gas introduction flow rate is controlled to be constant, and the degree of vacuum (pressure) of the entire container is controlled to be constant by controlling the exhaust flow rate.

The introduced gas may be introduced from the plasma generating section E, or may be introduced from both the plasma processing section (processing section) T and the plasma generating section E. When the gas is introduced from both the process section and the plasma generation section, the type of gas may be different.

When a reactive gas is not used, a reactive gas is used as appropriate, in addition to a rare gas (usually, Ar or He) for maintaining a constant pressure. The reactive gas reacts with evaporated particles (plasma particles) using a cathode material or the like as a source, so that a double compound film can be easily formed. Examples of the reactive gas include nitrogen (N ₂ ),
Oxygen (O ₂ ), hydrogen (H ₂ ), hydrocarbon gas (C ₂ H
₂ , C ₂ H ₄ , CH ₄ , C ₂ H ₆ ) and carbon oxide gas (CO, CO ₂ ). Here, in order to control the reactivity, the rare gas may be mixed to adjust the concentration of the reactive gas.

In the plasma processing method of the present embodiment,
In the above-described basic configuration, the plasma P immediately after the discharge is bent and moved by the magnetic field induction to the plasma processing part T, and the cathode material fine particles (droplets) d by-produced from the cathode 12 when the plasma is generated are removed. This is a method in which the liquid is moved to a droplet collecting section D which does not interfere with the above and is collected and deposited.

The droplet generated from the cathode is electrically neutral, and is generally not affected by a magnetic field, and thus has a characteristic of moving straight. Therefore, a space for capturing and collecting droplets, that is, a droplet collecting portion D is provided at a position facing the cathode 12. Basically, it suffices to simply extend the vacuum chamber 10 for forming the plasma generating section E in the direction of the plasma emission axis. In a normal case, droplets that have moved straight (straight flight) accumulate on the inner wall of the droplet collecting unit D. Here, if the droplet collecting portion D is configured to be detachable, the cleaning becomes easy.

Then, a plasma guide section G provided with a plasma induction magnetic field generator (plasma bending magnetic field generator) 28 for generating an induction magnetic field for bending and moving the plasma to the plasma processing section T is provided.

The plasma guide section G includes a plasma generating section E
And a part connecting the droplet collecting part D and the processing part T, and by applying an induction magnetic field from the outside,
The plasma flow P from the plasma generation unit E is substantially perpendicular (85
(９５95 °) to guide (guide) to the plasma processing portion T. The flow of the droplet becomes a straight flow without being affected (action) by the magnetic field. The droplets are not included in the plasma guided to the plasma processing unit T through the plasma guide unit G.

The above-mentioned plasma bending magnetic field generator 28 is usually in a direction perpendicular to the magnetic field (magnetic field) of the magnet 18b on the plasma advancing side (front side) of the arc stabilizing magnetic field generator 18 and in the forward direction (the same direction). ) Generates a pair of mirror-shaped applied magnetic fields. The mirror-shaped applied magnetic field has a function of narrowing the plasma into a beam and inducing the plasma in the forward direction. By this action, the magnetic field of the plasma P is guided to the plasma guide portion G and further to the plasma processing portion T. The direction of the magnetic field of the front magnet 18b of the plasma bending magnetic field generator 28 and the arc stabilizing magnetic field generator 18 is not limited to the co-current direction with the plasma flow, but may be the counter current direction as shown in FIGS.

A DC bias, an RF bias or a pulse bias may be applied to the substrate (processed portion) 30 in order to control the film quality of the generated film. In particular, by applying a high-voltage pulse bias, ions in the plasma
It is injected into the surface layer and enables a high-level modification treatment of the substrate surface. When a pulse power supply is used as the arc power supply 22, it is desirable to control the timing between the power supply and the bias.

Incidentally, a plurality of cathodes 12 may be arranged in the vacuum chamber 10. By using a plurality of cathodes 12,
Productivity is improved.

FIGS. 2 and 3 are model diagrams in which a part of the plasma processing apparatus shown in FIG. 1 (particularly, a droplet collecting section D1 or D2) is partially omitted. The same parts as those in FIG. 1 are denoted by the same reference numerals, and all or part of their description will be omitted. Hereinafter, the same applies to FIGS.

FIG. 2 shows an improvement in the droplet collection efficiency and the transfer efficiency (transport efficiency) of the plasma to the plasma processing section T. The main differences from the apparatus of FIG. 1 are as follows. The direction in which the plasma flow P is bent by the magnetic field is 20 to 80 ° (preferably 30 to 60 °) with respect to the plasma emission axis of the plasma generating unit E, and the tip end of the droplet collecting unit D1 is closed. The cylindrical body 32 is provided with an opening 32a facing the discharge direction of the droplet, and is curved in a direction that does not interfere with the magnetic field bending direction of the plasma.

That is, the angle of inclination (intersection angle) of the plasma generating section E with respect to the plasma emission axis with respect to the plasma emission axis may be about 90 ° or larger than 90 ° as shown in FIG. Smaller, ie 8
By setting the angle to 0 ° or less, the intensity of the applied magnetic field in the plasma guide portion G can be reduced (that is, in the case of an electromagnetic coil, power consumption can be reduced). This is because, since the bending angle of the plasma is small, the narrowing energy for bending the plasma is small.

Also, as shown in FIG.
From the viewpoint that the escape (loss) of the plasma to the droplet collecting portion D1 is reduced as compared with the case where the plasma is moved by bending at an angle greater than 0 °, the plasma transfer efficiency to the plasma processing portion T ( Transport efficiency) is increased. If the bending angle is too small (less than 20 °), the amount of droplets mixed into the plasma guide portion G increases, and the efficiency of droplet removal decreases.

Further, as shown in the example, by forming the vacuum chamber for forming the droplet collecting portion D1 with the curved cylindrical body 32, the plasma of the solid droplet can be reduced as compared with the above configuration shown in FIG. Can be reduced.

The molten liquid droplets are transferred to the cylindrical body 32.
1 is attached to the inner wall of the cylindrical body (collector), the solid droplet repeatedly reflects irregularly on the inner peripheral wall of the cylindrical body (collector) 32, and proceeds deep into the collector. Eventually, it loses kinetic energy and stops at the end of the tubular body 32.
Therefore, this configuration is effective in the case of a graphite cathode that generates solid droplets.

In particular, when the cylindrical body 32 has a structure in which the radius is continuously reduced (for example, a horn shape or a square shape) or the radius is reduced stepwise (stepwise), a solid droplet is used. Movement in the direction of plasma flow due to repeated reflection of light is less likely to occur. Therefore, when the cylindrical body 32 has such a structure, it can be more reliably prevented from being mixed into the plasma flow.

The cylindrical body 32 may be oriented in the horizontal direction on a plane, but it is more desirable that the cylindrical body 32 be bent downward because the sedimentation action of gravity can be used.

Further, in FIG. 2, plasma bending is performed by applying a magnetic field for increasing the speed of the plasma flow to the plasma guide portion G around the outer periphery of the base portion of the cylindrical body 32 which is the connection portion of the droplet collection portion. An auxiliary magnetic field generator (magnet) 34 is provided. The auxiliary magnetic field generator 34 applies a magnetic field in the opposite direction to the magnetic field (magnetic field) generated by the plasma bending magnetic field generator 28, and forms a cusp-shaped magnetic field pair therebetween. By the action of the cusp magnetic field pair, the plasma is diffused in the direction of the bent flow and contributes to an increase in the plasma density. That is, the plasma transfer (transport) efficiency can be further improved.

In FIG. 3, the droplet collecting portion D2 is formed of a substantially square cylindrical body (box-like body) 33, and the inlet (droplet collecting port) 33a of the chamber 33 is formed.
And a reflecting plate 3 for bending the droplet into the cylindrical body.
9 and a droplet energy absorber (hereinafter, referred to as a “droplet absorber”) 40 for absorbing the kinetic energy of the droplet is provided on the opposite surface side and the bottom side of the box-shaped body 33 in the droplet advancing direction. It was done. The solid-state droplet d coming straight from the plasma generation unit E by the reflection plate 39 is collected by the droplet collection unit D2.
Can be reliably guided to In addition, the droplet absorber 40
Accordingly, it is possible to prevent the droplet d from being mixed into the plasma due to the rebound of the droplet (diffuse reflection). It is desirable that the energy absorber (buffer) 40 has heat resistance and can capture droplets.
Ceramic / quartz / carbon wool, carbon fiber, carbon microcoil, sponge-like carbon, porous carbon / ceramic and the like can be mentioned.

The droplet absorber 40 may be merely arranged in layers on the side of the droplet advancing surface and / or on the bottom side as shown in the figure, but the tubular bodies (box-like bodies) 32, 3
3 may be formed in a layer on the entire peripheral wall, or may be formed in the entire space of the droplet absorbing portions D and D1. In the case of forming a layer, the thickness is usually 2 to 10 mm.

FIGS. 4, 5, and 6 show model diagrams of a plasma processing apparatus according to still another embodiment of the present invention.

These plasma processing methods are described in FIGS.
Basically, the point different from 3 is that the plasma flow is diffused by the induced magnetic field so as to be directed to the donut-shaped plasma processing portion T1. And the droplet collecting unit D
2 (D3) is provided at a position facing the plasma generating portion E, that is, at a position inside the donut-shaped plasma processing portion T1 similarly to the case shown in FIGS. As described above, the plasma generation unit and the droplet collection unit may be arranged in parallel in the horizontal direction. However, as shown in the figure, the arrangement in the vertical direction together with the plasma processing unit T1 makes use of gravity when collecting droplets. It is desirable because it can.

The plasma generating section E1 is the same as the apparatus shown in FIG. The difference is that the plasma generation section E1 and the plasma processing section T1 are directly connected without passing through the plasma guide section, and that the droplet collection sections D1 and D2 are directly connected to the plasma processing section T1.

The arc plasma generated in the plasma generating section E1 is subjected to a plasma diffusion arranged at the boundary between the plasma processing section and the droplet collecting section D3 with respect to the magnetic field generated by the stabilizing magnetic field generator 18 in the plasma generating section E1. By forming a cusp magnetic field pair in which the magnetic field generated by the magnetic field generator 36 is in the opposite direction, the magnetic field is diffused and the plasma flow spreads in a flat cylindrical shape. That is, the result is that the plasma flow flows toward the cylindrical plasma processing portion T1. At this time,
Since the droplet flow is a straight (downward) flow, the droplet flies inside the cylindrical plasma processing portion T1 and exists, but the droplet-free plasma region and the plasma processing portion T1 exist in the outer peripheral region. Can be formed. If the substrate (substrate to be processed) 30 is arranged at the outer peripheral position of the plasma, it is possible to perform processing without being affected by droplets.

When the vacuum chamber 10A (10B) of the plasma processing section T1 is connected to the anode side of the arc power supply 22 and is set to the same potential as the anode 14, the plasma spreads in a flat columnar shape (disk shape). As the plasma density increases, the plasma processing (surface treatment) process becomes more efficient.

The plasma diffusion magnetic field generator 36 may be provided outside the vacuum chamber as shown in FIG. Further, in this embodiment, as shown in the figure, a plasma diffusion auxiliary magnetic field generator 38 for controlling the spread of plasma can be provided. The auxiliary magnetic field generator 38 forms a mirror-shaped applied magnetic field pair in the same direction with respect to the magnetic field of the plasma stabilizing magnetic field generator 18, and applies a cusp-shaped applied field in the opposite direction to the magnetic field of the plasma diffusion magnetic field generator 36. Form a magnetic field pair.
Therefore, by increasing the magnetic velocity density of the auxiliary magnetic field generator 38, the plasma diffusion force of the cusp magnetic field pair can be adjusted.

The droplet collecting portion D2 in FIG. 3 is formed of a tapered cylindrical body (a cone, a polygonal pyramid, or the like) that is continuously reduced in diameter and closed continuously to the peripheral wall of the vacuum chamber forming the plasma processing portion. . Due to the shape, irregular reflection of the solid droplet to the plasma processing portion T1 can be reduced. The taper angle at this time is 60 ° or less, preferably 45 ° or less with respect to the chamber axis (vertical axis). This is because the upward reflection (bounce) of the droplet that has proceeded straight in the substantially axial direction is likely to be directed upward. That is, at 60 °, the reflection angle is upward by 30 °, and at 45 °, it is horizontal. The degree of taper angle is not particularly limited, but is set to about 30 ° from the viewpoint of compactness of the apparatus and the capacity of collecting droplets.

FIG. 5 shows a simplified type of the apparatus shown in FIG. 4, in which the droplet collecting section D3 is also used as the flat bottom wall section 10b of the vacuum chamber 10B forming the plasma processing section T1. 10, a magnetic field generator 36 for plasma diffusion (deflection) is arranged below the outside of the apparatus. When the droplets generated from the cathode 12 are only liquid and the droplets are not reflected on the inner wall of the vacuum chamber, the droplet collecting portion can be replaced by a part of the inner wall of the vacuum chamber 10B forming the plasma processing portion T1. Such shapes are available. In the case of this configuration, it is easy to arrange the magnetic field generator 36 for forming the plasma into a column shape outside the container, and the apparatus becomes simpler.

It is desirable to dispose the above-described droplet absorber on the flat bottom wall 10. This is because the positions of the droplet collecting unit D4 and the plasma processing unit T1 are close to each other, and the droplets are likely to be mixed into the plasma due to diffuse reflection.

[0075]

[Experimental example] Using a conventional commercially available vacuum arc deposition apparatus and a plasma processing apparatus (vacuum arc deposition apparatus) shown in FIG.
Cathode: Ti, anode: copper , introduction gas as O ₂ ,
A TiO ₂ film was formed on a general-purpose glass substrate.

The chamber pressure was 0.5 Pa, the arc current was 50 A, and the film formation time was 5 min.

With respect to the TiO ₂ films obtained above,
When observed with an optical microscope photograph, droplets were observed in the conventional one, whereas almost no droplets were observed in the present embodiment.

[Brief description of the drawings]

FIG. 1 is a schematic model diagram showing one embodiment of a plasma processing apparatus (vacuum arc deposition apparatus) using the present invention for a plasma processing method.

FIG. 2 is a partially omitted main part model diagram of an apparatus obtained by improving a part of the plasma processing apparatus (a droplet collecting section and the like) in FIG.

FIG. 3 is a partially omitted main part model diagram of another improved device.

FIG. 4 is a schematic model diagram showing another embodiment of a plasma processing apparatus using the present invention for a plasma processing method.

FIG. 5 is a schematic model diagram showing a simplified type in FIG. 4;

6 is an arrangement plan view of a substrate (workpiece) in a plasma processing unit of the apparatus of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Vacuum chamber 12 Cathode 14 Anode 16 Trigger electrode 18 Arc stabilizing magnetic field generator 22 Arc power supply 28 Plasma guide magnetic field generator (plasma induction magnetic field generator) 30 Substrate (workpiece) 32 Cylindrical body 34 Plasma bending auxiliary magnetic field generator (plasma induction magnetic field generator) 36 Plasma diffusion magnetic field generator (plasma induction magnetic field generator) 38 Plasma diffusion auxiliary magnetic field generator (plasma induction magnetic field generator) 39 droplet reflector 40 droplet energy Absorber E Plasma generator D, D1, D2, D3, D4 Droplet collector G Plasma guide T Plasma processing P Plasma

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K029 BA17 BA48 CA04 CA10 DD06 EA06 4K030 AA09 AA14 AA18 CA17 FA01 FA14 JA04 KA30 KA34 4K057 DD01 DE20 DM21

Claims (13)

[Claims] 1. A vacuum arc discharge is performed in a vacuum atmosphere into which a reactive gas is introduced as necessary, to generate plasma, and the plasma is caused to flow into a plasma processing section, and an object to be processed arranged in the plasma processing section is generated. A surface treatment process using plasma, wherein the plasma flow from the plasma generation unit is bent or diffused in a direction not facing the plasma generation unit by magnetic field induction to flow into the plasma processing unit, and the plasma generation is performed. A plasma processing method comprising collecting cathode material fine particles (hereinafter, referred to as “droplets”) by-produced from a cathode when plasma is generated at a position facing a portion. 2. The method according to claim 1, wherein the bending angle of the plasma flow is approximately 20 to 80 with respect to the plasma emission axis of the plasma generating unit.
2. The plasma processing method according to claim 1, wherein the angle is set to degrees. 3. A droplet collecting port is provided at a position facing the plasma generating section, and the droplet is collected by a cylindrical body continuous with the droplet collecting port. 2. The plasma processing method according to 2. 4. The plasma processing method according to claim 1, wherein the plasma flow is bent by a magnetic field so as to be directed to a donut-shaped plasma processing portion. 5. The method according to claim 5, wherein the reactive gas is N_Two , O_Two , H
_Two , CH_Four , C_Two H _Two , C_Two H_Four , C_Two H₆ , CO and
CO_Two Using one or more selected from the group of
The pressure of the vacuum atmosphere is 10 to 10^-FiveTo be Pa
The plasma processing according to claim 1, 2, 3, or 4, wherein
Law. 6. A vacuum chamber, comprising: a plasma generating section; a plasma processing section; and a droplet collecting section at a portion not interfering with the plasma processing section, wherein a plasma flow from the plasma generating section is subjected to the plasma processing. And a plasma induction magnetic field generator for generating an induction magnetic field that bends or diffuses toward the portion. 7. The plasma processing apparatus according to claim 6, wherein the plasma processing unit is disposed at a position orthogonal to the plasma generating unit, and the droplet collecting unit is disposed at a position facing the plasma processing unit. . 8. The plasma guide section connecting the plasma generating section and the plasma processing section has an intersection angle of 20 to 80 ° with respect to a plasma emission axis of the plasma generating section, and the droplet collecting section has a tip end. 7. The plasma processing apparatus according to claim 6, wherein the cylindrical body is formed as a closed cylindrical body, and the cylindrical body has a droplet collecting port at a position facing the plasma generating portion. 9. The plasma processing apparatus according to claim 8, wherein a reflector that bends the droplet into the cylindrical body is disposed at the droplet collecting port. 10. A plasma induction magnetic field generator (plasma diffusion magnetic field generator) for diffusing plasma so that a plasma flow is directed to the plasma processing unit, wherein the plasma processing unit is arranged in a donut shape. The plasma processing apparatus according to claim 6, wherein a collecting unit is disposed inward of the donut-shaped plasma processing unit. 11. A tapered cylinder in which the plasma diffusion magnetic field generator is disposed in the vacuum chamber on the bottom side of the plasma processing section, and the diameter of the plasma diffusion magnetic field generator is reduced downward and continuous with a peripheral wall of the vacuum chamber forming the plasma processing section. The plasma processing apparatus according to claim 10, wherein the droplet collecting portion is formed in a shape. 12. The droplet collecting section also serves as a flat bottom wall of a vacuum chamber forming a plasma processing section, and the plasma diffusion magnetic field generator is disposed below and outside the flat bottom wall. The plasma processing apparatus according to claim 11, wherein: 13. A droplet energy absorber for absorbing kinetic energy of a droplet is disposed in the droplet collecting section. 13. The plasma processing apparatus according to item 12.