JP2003080060A - Discharge plasma treating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge plasma treating apparatus capable of coping even with the treatment of a large surface area base material, or the like, by moderating the drift of a gas introduced between electrodes in the remote type discharge plasma treating apparatus. SOLUTION: In the discharge plasma treating apparatus in which glow discharge plasma is produced by introducing a treating gas between the opposed electrodes and applying electric field, the introduction of the treating gas between the opposed electrodes is uniformly performed by using a flow straightening mechanism provided with a rotary blade.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge plasma processing apparatus, and more particularly to an electric discharge plasma processing apparatus having an apparatus capable of uniformly introducing a processing gas between electrodes.

[0002]

2. Description of the Related Art Various methods have been developed for manufacturing a semiconductor device by forming a thin film on a substrate by a chemical vapor deposition (CVD) method or the like, but a uniform reaction gas flow is formed on a substrate surface. It is known to affect the homogeneity of thin films,
In particular, when forming a thin film on a large area substrate, the flow velocity and concentration of the reaction gas have a great influence on the formation of the thin film.

As a method for making the reaction gas uniform with respect to the surface of the substrate, for example, a method using a shower plate using a porous material, as described in JP-A-8-209349, A method using a rectifying fin as described in 2001-140078 can be mentioned. However, it cannot be said that the gas introduction flow and the gas introduction method have been sufficiently solved.
Furthermore, a sufficient effect is not exerted on the nonuniform flow of gas, and in particular, in the thin film forming method by the plasma discharge treatment, it was necessary to solve the nonuniform flow problem.

Further, in a general atmospheric pressure plasma processing method, JP-A-6-2149 and JP-A-7-85997 are used.
As described in Japanese Laid-Open Patent Publication No. 2004-242, mainly, inside the processing tank, the object to be processed is installed between the parallel plate electrodes covered with the solid dielectric, etc., and the processing gas is introduced into the processing tank, and between the electrodes. A method of applying a voltage and treating the object to be treated with the generated plasma is adopted. According to such a method, the entire object to be processed is placed in the discharge space, and there is a problem that the object to be processed is likely to be damaged.

In order to solve such a problem, a plasma gas blow-out port is provided at the tip as an apparatus which can easily perform plasma treatment only on a specific portion of an object to be treated and can continuously treat the object to be treated. A remote type plasma processing apparatus having the same has been developed. For example, JP-A-11-251304 and JP-A-11-2605.
In Japanese Patent Publication No. 97, a cylindrical reaction tube having an outer electrode and an inner electrode are provided inside the reaction tube, cooling means is provided at both electrodes, glow discharge is generated inside the reaction tube, and plasma is generated from the reaction tube. A plasma processing apparatus has been disclosed in which a jet is blown and blown onto an object to be processed, and a remote type plasma processing apparatus in which a long nozzle is provided at the tip of a parallel plate type electrode capable of processing a larger area substrate has been developed. ing.

However, in the above remote type plasma processing apparatus, particularly when the plasma generated between the parallel plate type electrodes is used to process the surface of a large area substrate from a long nozzle, the processing gas introduced between the electrodes is changed. If the flow rate and the flow velocity are distributed and the gas introduction flow becomes uneven, the plasma flow blown toward the base material will have density variations, which will affect the uniformity of the thin film formed on the base material surface. There was a problem of exerting it.

[0007]

DISCLOSURE OF THE INVENTION In view of the above problems, the present invention is a remote type discharge plasma processing apparatus, in which a nonuniform flow of gas introduced between electrodes is mitigated to enable processing of a large area substrate or the like. An object is to provide a plasma processing apparatus.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has provided a rotating vane (propeller) mechanism in a gas rectifying unit in order to alleviate a nonuniform flow of gas introduced between electrodes. The inventors have found that by stirring a biased gas flow, the local gas flow can be made to flow over the entire rotating blade, and the gas can be uniformly introduced between the electrodes, and the present invention has been completed.

That is, the first aspect of the present invention is a discharge plasma processing apparatus configured to introduce a processing gas between opposed electrodes and apply an electric field to generate glow discharge plasma. The discharge plasma processing apparatus is characterized in that the processing gas can be uniformly introduced between the electrodes by a rectifying mechanism using a rotating blade.

The second invention of the present invention is described in the first invention, wherein the counter electrode is an electrode in which at least one of the counter surfaces of the counter electrode is covered with a solid dielectric. It is a discharge plasma processing apparatus.

A third invention of the present invention is the discharge plasma processing apparatus according to the first or second invention, wherein glow discharge plasma is generated under a pressure near atmospheric pressure. .

Further, a fourth invention of the present invention is characterized in that the counter electrode is a parallel plate type electrode, and the generated discharge plasma is sprayed onto a substrate to be processed placed outside the discharge space. The discharge plasma processing apparatus according to any one of the first to third inventions.

In a fifth aspect of the present invention, the electric field has a voltage rise time of 10 μs or less and an electric field intensity of 10 to 1
The discharge plasma processing apparatus according to any one of the first to fourth inventions, which is a pulsed electric field of 000 kV / cm.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The discharge plasma processing apparatus of the present invention is a discharge plasma adapted to generate glow discharge plasma by introducing a processing gas between opposed electrodes and applying an electric field, preferably a pulsed electric field. In the processing apparatus, in particular, in a remote type plasma processing apparatus in which discharge plasma generated between parallel plate type electrodes is sprayed from a long nozzle onto the surface of a substrate to be processed, the flow rate and flow velocity of the processing gas in the processing gas introduction part Introducing a rectifying mechanism with rotating blades to alleviate the uneven flow that causes the distribution, the gas flow introduced between the electrodes is made uniform, and the plasma flow blown toward the substrate to be processed is made uniform. It is a device. The details will be described below.

The discharge plasma processing apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a perspective view of an example of the device of the present invention. In FIG. 1, the processing gas is introduced into the gas introduction chamber 5 through the gas blowing port 6, and the gas introduction chamber 5
Parallel plate type electrode 1
And 2 is blown into the discharge space 3 from the slit-shaped gas blowing port 7 corresponding to the length of the discharge space 3. The processing gas blown into the discharge space 3 is excited and turned into plasma, and is sprayed from the plasma outlet 4 onto the surface of the substrate 20 to be processed.

FIG. 2 is a side sectional view of an example of the gas introducing chamber provided with the flow regulating mechanism used in the present invention, and FIG. 3 is a schematic perspective view partially seen from the lower side of the gas introducing chamber. The gas introduction chamber 5 is divided into a primary chamber 10 and a secondary chamber 11, a plurality of primary gas outlets 12 are provided from the primary chamber 10 to the secondary chamber 11, and a primary gas outlet 12 is provided on the secondary chamber side. Corresponding to the above, a plurality of rotary blade mechanisms in which a plurality of rotary blades 13 are attached to the rotary shaft 14 are provided. The processing gas is introduced into the primary chamber 10 through the gas blowing port 6, is made substantially uniform in the primary chamber, and then the plurality of primary gas blowing ports 1 are provided.
2 is introduced into the secondary chamber 11. The processing gas introduced into the secondary chamber collides with the rotating blade 13 and rotates the rotating blade 13, and at the same time, the processing gas is agitated and rectified by the rotating blade 13 into the discharge space 3 from the slit-shaped gas outlet 7. Sent in.

The rotary vane mechanism is provided corresponding to the primary gas outlet 12 on the secondary chamber side, and is rotated without using power by the gas flow flowing from the primary gas outlet 12 into the secondary chamber. Even if it is designed to
It may be configured to rotate by power, or may have a mechanism in which the rotating shaft swings its head. Rotating blade 1
The number 3 is attached to the rotary shaft 14, but the number of the number 3 is not limited, and it is preferable that the number 3 can be attached and detached according to the kind of the processing gas to be used. The mounting angle of the rotary blade 13 to the rotary shaft 14 is 0 to 90.
It is attached so that it can be changed appropriately within the range of °.
Further, the material of the rotary blade 13 is not particularly limited,
Depending on the type of processing gas used, polytetrafluoroethylene resin, nylon resin, metal, etc. may be mentioned.

The primary chamber and the secondary chamber may be provided with a baffle plate, a perforated plate, an air flow direction changing function plate, etc. for promoting uniformization and flow rectification of the gas flow of the processing gas. Further, the shape of the primary gas outlet 12 may be a nozzle shape that can accelerate the rotation of the rotary blades. In particular, when using a plurality of types of processing gas or when using a mixed gas of a processing gas and a diluent gas, it is preferable that the device is devised so as to avoid non-uniformity at the time of supply, especially in a large area. When applied to an object to be processed or when a plurality of gases having large differences in specific gravity are used, the apparatus of the present invention is effective because it tends to become non-uniform.

In the discharge plasma processing apparatus of the present invention,
The processing pressure for generating the discharge plasma is preferably under atmospheric pressure, and specifically, 1.333 × 10 5.
A pressure of ^{4 to} 10.664 × 10 ⁴ Pa is preferable. Above all, pressure adjustment is easy and the device is simple.
The range of 10 ^{4 to} 10.397 × 10 ⁴ Pa is particularly preferable.

Examples of the material of the counter electrode used in the apparatus of the present invention include those made of simple metals such as copper and aluminum, alloys such as stainless steel and brass, and intermetallic compounds. The counter electrodes preferably have a structure in which the distance between the counter electrodes is substantially constant in order to avoid occurrence of arc discharge due to electric field concentration. Examples of the electrode structure that satisfies this condition include a parallel plate type, a cylinder facing flat plate type, a sphere facing flat plate type, a hyperboloid facing flat plate type, and a coaxial cylindrical type structure. It is preferable to use an electrode having a remote type structure in which the plasma generated in the discharge space is sprayed onto the substrate to be processed installed outside the discharge space. With such a structure, the substrate to be treated is not directly exposed to the high electric field plasma space, and the gas in the plasma state is carried only to the surface to perform the treatment, thereby reducing the electrical and thermal load. To be done.

The solid dielectric covering the electrodes is placed on one or both of the facing surfaces of the electrodes. At this time, the solid dielectric and the electrode on the installed side are in close contact with each other, and the facing surface of the contacting electrode is completely covered. If there is a portion where the electrodes directly face each other without being covered with the solid dielectric, arc discharge easily occurs from there.

The solid dielectric may have a sheet shape or a film shape, but preferably has a thickness of 0.01 to 4 mm. If it is too thick, a high voltage is required to generate discharge plasma, and if it is too thin, dielectric breakdown occurs when a voltage is applied and arc discharge easily occurs.

As the material of the solid dielectric, for example,
Examples thereof include plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, metal oxides such as silicon dioxide, aluminum oxide, zirconium dioxide and titanium dioxide, complex oxides such as barium titanate, and those having a multilayer structure. To be

The solid dielectric material preferably has a relative dielectric constant of 2 or more (in a 25 ° C. environment, the same applies hereinafter).
Specific examples of the dielectric material having a relative dielectric constant of 2 or more include polytetrafluoroethylene, glass, metal oxide film and the like. In order to stably generate high-density discharge plasma, it is preferable to use a fixed dielectric having a relative dielectric constant of 10 or more. Although the upper limit of the relative permittivity is not particularly limited, it is known that the actual dielectric constant is about 18,500. As the solid dielectric having a relative dielectric constant of 10 or more, for example, a metal oxide film mixed with 5 to 50% by weight of titanium oxide and 50 to 95% by weight of aluminum oxide, or a metal oxide film containing zirconium oxide. Those consisting of are preferred.

The distance between the electrodes coated with the solid dielectric is appropriately determined in consideration of the thickness of the solid dielectric, the magnitude of the applied voltage, the purpose of utilizing plasma, etc.
It is preferably 50 mm, more preferably 5 mm
It is the following. When it exceeds 50 mm, it is difficult to generate uniform discharge plasma.

An electric field is applied to the counter electrode to generate plasma, and it is particularly preferable to apply a pulsed electric field.

The rise time and fall time of the pulsed electric field are preferably 10 μs or less. If it exceeds 10 μs, the discharge state easily shifts to an arc and becomes unstable, and it becomes difficult to obtain a high-density plasma state by a pulsed electric field. Further, the shorter the rise time and the fall time are, the more efficiently the gas is ionized at the time of plasma generation, but it is difficult to realize the pulse electric field having the rise time of less than 40 ns. More preferably, it is 50 ns to 1 μs. Note that the rising time referred to here means the time when the voltage (absolute value) continuously increases, and the falling time means the time when the voltage (absolute value) continuously decreases.

Further, it is preferable that the fall time of the pulsed electric field is also steep, and the same 10 μm as the rise time.
It is preferable that the time scale is s or less. For example, in the power supply device used in the embodiment of the present invention, the rise time and the fall time can be set to the same time, although it depends on the pulse electric field generation technique.

The electric field strength of the pulse electric field is 10 to 10
00 kV / cm, preferably 20 to 300 kV /
cm. If the electric field strength is less than 10 kV / cm, the treatment takes too long, and if it exceeds 1000 kV / cm, arc discharge is likely to occur.

The frequency of the pulsed electric field is 0.5 kHz.
The above is preferable. If it is less than 0.5 kHz, the plasma density is low and the treatment takes too long. The upper limit is not particularly limited, but is commonly used 13.56M
A high frequency band such as Hz or a test-use 500 MHz may be used. Considering the ease of matching with the load and the handling property, the frequency is preferably 500 kHz or less. By applying such a pulsed electric field, the processing speed can be greatly improved.

Further, one pulse duration in the above pulsed electric field is preferably 200 μs or less, more preferably 3 to 200 μs. 200 μs
When it exceeds, it becomes easy to shift to arc discharge. Here, one pulse duration is an example shown in FIG. 9, but refers to the continuous ON time of one pulse in a pulse electric field consisting of repeated ON and OFF.

The processing gas used in the discharge plasma processing apparatus of the present invention is not particularly limited as long as it is a gas which generates plasma by applying an electric field, preferably a pulsed electric field, and various gases are used depending on the processing purpose. it can.

For example, as the processing gas, CF ₄ , C
_A water-repellent surface can be obtained by using a fluorine-containing compound gas such as ₂ F ₆ , CClF ₃ , or SF ₆ .

Oxygen element-containing compounds such as O ₂ , O ₃ , water and air, nitrogen element-containing compounds such as N ₂ and NH ₃ and sulfur element-containing compounds such as SO ₂ and SO ₃ are used as processing gases. Then, a hydrophilic surface can be obtained by forming hydrophilic functional groups such as carbonyl group, hydroxyl group and amino group on the surface of the base material to increase the surface energy. Further, the hydrophilic polymer film can be deposited by using a polymerizable monomer having a hydrophilic group such as acrylic acid or methacrylic acid.

Further, using a processing gas such as a metal-hydrogen compound, a metal-halogen compound, a metal alcoholate of a metal such as Si, Ti or Sn, SiO ₂ , TiO ₂ , SnO is used.
A metal oxide thin film such as ₂ is formed and is electrically and
Optical function can be given, and halogen gas is used for etching and dicing, oxygen gas is used for resist treatment and removal of organic contaminants, and inert gas such as argon and nitrogen is used. Surface cleaning and surface modification can also be performed with plasma.

From the viewpoint of economy and safety, it is preferable that the processing gas is processed in an atmosphere diluted with a diluent gas as described below, rather than in a single atmosphere. As the diluent gas, helium, neon, argon,
Examples include rare gases such as xenon, nitrogen gas, and the like. You may use these individually or in mixture of 2 or more types. When a diluting gas is used, the concentration of the processing gas is preferably 0.001 to 10% by volume in the mixed gas of the processing gas and the inert gas, and more preferably 0.001 to 0.3%.
% By volume.

Examples of the substrate to be treated by the discharge plasma treatment apparatus of the present invention include polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, polytetrafluoroethylene, plastics such as acrylic resin, glass, ceramic, metal and the like. To be Examples of the shape of the substrate include a plate shape and a film shape, but are not particularly limited thereto. According to the surface treatment method of the present invention, it is possible to easily deal with the treatment of substrates having various shapes.

In the atmospheric pressure discharge using a pulsed electric field using the device of the present invention, it is possible to directly generate the discharge between the electrodes under the atmospheric pressure without depending on the gas species, and it is further simplified. It is possible to realize high-speed processing with an electrode structure, an atmospheric pressure plasma device by a discharge procedure, and a processing method. In addition, parameters related to processing can be adjusted by parameters such as pulse frequency, voltage, and electrode interval.

[0039]

EXAMPLES The present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1 (1) Flow velocity distribution Using the gas introduction chamber (rectifier) shown in FIGS. 2 and 3, the flow velocity distribution when the rectified gas was fed into the discharge space was measured. In FIG. 2, the gas introduction chamber 5 provided with the gas injection port 6 of 5 mmφ has a width of 100 mm, a length of 140 mm, and a height of 200.
mm, it is divided into a primary chamber 10 and a secondary chamber 11, six primary gas outlets 12 are provided with a pitch of 2 mmφ and a pitch of 20 mm, and eight propellers of 10 mmφ rotate at an angle of 45 degrees on the secondary chamber side. Three rotary vane mechanisms attached to the shaft were attached corresponding to the primary gas blowout ports 12, and the gas blowout ports 7 had a slit shape of 5 mm × 100 mm. As gas, 10 L / min of air was introduced into the primary chamber 10 through the gas blowing port 6, and the flow velocity at each position in the length direction of the gas blowing port 7 was measured. The result is shown in FIG. 4 together with the flow velocity in the case of the comparative example in which the propeller is not attached.

As is apparent from FIG. 4, by providing the propeller mechanism in the secondary chamber, the flow velocity at each position of the gas outlet 7 became almost constant. On the other hand, when the propeller mechanism was not provided in the secondary chamber, the flow velocity distribution at each position of the gas outlet 7 was greatly disturbed.

(2) Discharge plasma treatment Next, the size of the gas outlet 7 of the rectifier is set to 2 mm.
Change to a slit of × 100mm and use parallel plate type electrodes
Plasma gas treatment by introducing the treatment gas into the discharge space
went. For the electrode, use 1 alumina as a solid dielectric
300 mm long × 100 mm wide sprayed to a thickness of mm
2 mm of SUS304 parallel plate type electrodes with a thickness of 20 mm
Installed in parallel at intervals of
Silicon nitride film formed at a position 5 mm away 100 mm ×
A wafer of 100 mm × 50 μm in thickness is used as a substrate to be processed.
Installed. 1.333 × 1 for the entire device with an oil rotary pump
0 ²Evacuate to Pa and then fill with argon gas.
10.13 × 10^FourAfter setting to Pa, with the processing gas
And then CH₃Si (OCH₃)₃0.2%, CH_Four0.2%
Gas injection of mixed gas diluted with argon gas
Introduced through the mouth 6, turned into plasma in the discharge space and placed on the wafer
When sprayed and film-formed, siloxane-based thin film on the substrate
Visually confirm that the film is evenly and uniformly formed.
It was The electric field conditions are pulse rising speed 5 μs,
Frequency 10 kHz, peak-peak voltage 20 kV, 95
It was set under kPa (under atmospheric pressure).

[0043]

According to the discharge plasma processing apparatus of the present invention, since the processing gas rectified into discharge air can be introduced, a stable and uniform discharge plasma can be generated, and a large area substrate can be produced. Can be effectively used for processing such as.

[Brief description of drawings]

FIG. 1 is a schematic perspective view illustrating a discharge plasma processing apparatus of the present invention.

FIG. 2 is a side sectional view of a gas introduction chamber.

FIG. 3 is a schematic perspective view of a part of the gas introduction chamber seen from below.

FIG. 4 is a diagram showing a result of a flow velocity distribution in the example.

[Explanation of symbols]

1 and 2 electrodes 3 discharge space 4 Plasma outlet 5 Gas introduction chamber 6 gas inlet 7 gas outlet 10 Primary gas chamber 11 Secondary gas chamber 12 Primary gas outlet 13 Propeller (rotary blade) 14 rotation axis 20 substrate

Continued front page    F-term (reference) 4G075 AA24 BC01 BC04 BD03 CA14                       CA16 DA02 EB01 EB42 ED02                       ED06 ED08 FC15                 4K030 EA03 FA03 JA09 JA11 JA13                       JA14 KA12 KA14 KA15 KA47                 5F045 AA08 AC01 AC07 AE25 BB01                       EE20 EF13 EH08 EH13 EH18                       EH19

Claims (5)

[Claims] 1. In a discharge plasma processing apparatus configured to introduce a processing gas between opposed electrodes and apply an electric field to generate glow discharge plasma, the processing gas is introduced between the opposed electrodes by rotating blades. A discharge plasma processing apparatus characterized in that it can be uniformly introduced between electrodes by a rectifying mechanism. 2. The discharge plasma processing apparatus according to claim 1, wherein the counter electrode is an electrode in which at least one of the counter surfaces of the counter electrode is covered with a solid dielectric. 3. The glow discharge plasma is generated under a pressure near atmospheric pressure.
The discharge plasma processing apparatus according to. 4. The counter electrode is a parallel plate type electrode, and the generated discharge plasma is blown onto a substrate to be processed placed outside the discharge space. The discharge plasma processing apparatus according to item 1. 5. The electric field has a voltage rise time of 10 μs.
The discharge plasma processing apparatus according to any one of claims 1 to 4, wherein the electric field strength is a pulsed electric field having an electric field intensity of 10 to 1000 kV / cm.