JP2001156046A - Plasma processing apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly execute plasma processing in the width direction, without fluctuations, and moreover to easily manufacture a reaction vessel at a low cost. SOLUTION: A cylindrical reaction vessel 1 and a pair of electrodes 2, 3 are provided. A plasma generating gas is then supplied to the reaction vessel 1. The glow discharge is generated under the atmospheric pressure, to generate the plasma P from the plasma generation gas by applying an AC field into the reaction vessel 1, at the position corresponding to the area between the electrodes 2, 3. The plasma P is then supplied to the surface of an object 7 to be processed. A blowing port 4 for blowing the plasma P, generated within the reaction vessel 1 to the processing object 7 in the form of plasma jet, is formed in the reaction vessel 1. At least one of a pair of electrodes 2, 3 is provided at the external side of the reaction vessel 1. A sheet member 6, composed of a conductive material, is provided between the electrodes 2, 3 provided at the external side of the reaction vessel 1 and the reaction vessel 1. The sheet member 6 is provided in close contact with the external surface of the reaction vessel 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cleaning of foreign substances such as organic substances present on the surface of an object to be processed, peeling of resist, improvement of adhesion of an organic film, reduction of metal oxide,
The present invention relates to a plasma processing apparatus for generating plasma used for plasma processing such as film formation and surface modification, and a plasma processing method using the same. Particularly, the present invention relates to a surface of an electronic component requiring precise bonding. It is preferably applied to the cleaning of.

[0002]

2. Description of the Related Art Conventionally, attempts have been made to perform plasma processing under atmospheric pressure. For example, Japanese Unexamined Patent Publication No.
No. 1, JP-A-3-241739 and JP-A-1-241.
Japanese Patent No. 306569 discloses a method in which a pair of electrodes are arranged in a discharge space in a reaction vessel, a dielectric is provided between the electrodes, and the discharge space is mainly composed of a rare gas such as He (helium) or Ar (argon). There is disclosed a plasma processing method in which an object to be processed is filled with a gas for plasma generation and an AC electric field is applied between electrodes while an AC electric field is applied between electrodes on which a dielectric is arranged. Is applied to stably generate a glow-like discharge, and the glow-like discharge excites a plasma generation gas to generate plasma in a reaction vessel, and the plasma is used to process an object to be processed. It was made.

[0003] Japanese Patent Application Laid-Open Nos. 4-334543 and 5-202481 also describe that plasma treatment is performed under atmospheric pressure. In these publications, a plasma treatment is performed on the outer periphery of a cylindrical reaction tube. A plurality of electrodes are provided, an AC voltage is applied between the electrodes, plasma is generated in the reaction tube, and the object is introduced into the reaction tube where the plasma is generated to process the object. .

However, in the method described in the above publication, there is a problem that it is difficult to locally perform the plasma processing only on a specific portion of the processing object, and the processing time is long.
Therefore, plasma processing is performed by blowing plasma (particularly, active species of plasma) generated by glow-like discharge under atmospheric pressure into an object to be processed in the form of a jet. It has been proposed in JP-A-4-212253, JP-A-6-108257 and the like. The methods described in these publications are configured to locally jet plasma of an object to be processed by blowing out a jet-like plasma in a spot manner and spraying the plasma on the object.

However, the method of blowing out the plasma in a spot-like manner and spraying it on the object to be processed has a problem that it takes a long time to perform plasma processing on a large area of the object to be processed. Japanese Patent Application Laid-Open No. 4-358076 describes that plasma generated under atmospheric pressure is supplied to an object to be processed in a certain width to perform plasma processing. In this method, a pair of dielectric-coated electrodes having a solid dielectric disposed on the surface are arranged to face each other, a plasma generating gas is introduced from above from between the dielectric-coated electrodes, and a high voltage is applied to the dielectric-coated electrodes. Is applied to generate plasma from the plasma generation gas, and this plasma is supplied to the object to be processed downstream from between the dielectric coated electrodes. Also,
The specification and drawings attached to the application of Japanese Patent Application No. Hei 11-303117 also describe that plasma generated under atmospheric pressure is supplied to a workpiece with a certain width to perform plasma processing. . In this method, a reaction vessel is formed from an insulating material such as quartz glass, a slit-shaped wide outlet is formed on the lower surface of the reaction vessel, and a pair of electrodes are arranged outside the reaction vessel so as to face each other. By introducing a plasma generating gas into the reactor and applying a high voltage to the electrodes, plasma is generated from the plasma generating gas into the reaction vessel, and this plasma is blown out from the outlet and supplied downstream to the workpiece. Is what you do.

[0006]

However, in the above-described method of performing plasma processing by supplying plasma generated at atmospheric pressure to a workpiece with a certain width, the plasma processing is performed uniformly in the width direction. There was a problem that it was difficult. It is considered that this is because the adhesion between the solid dielectric or the reaction vessel and the electrode is low. That is, since the solid dielectric and the reaction vessel are formed by heating and fusing an insulating material (glass material) such as quartz glass, it is very difficult to keep the thickness of the solid dielectric and the reaction vessel uniform. In addition, the surface in contact with the electrode is formed to be uneven or curved. On the other hand, since the electrode is formed by machining metal or the like, the surface in contact with the solid dielectric or the reaction vessel is formed to be flat with almost no irregularities or curvature. Therefore, in the width direction of the solid dielectric or the reaction vessel,
Some parts of the solid dielectric or the surface of the reaction vessel are in contact with the electrode and some parts of the reaction vessel are not in contact with each other. As a result, the plasma processing was uneven in the width direction.

As one of the methods for solving such a problem, it is conceivable to control the thickness of the solid dielectric or the reaction vessel. In order to make the thickness uniform, polishing is performed after heat welding. And so on, and it is very difficult and expensive to produce a solid dielectric or a reaction vessel.

The present invention has been made in view of the above points, and enables plasma processing to be performed almost uniformly without unevenness. In particular, plasma processing in the width direction can be performed almost uniformly without unevenness. Moreover, it is another object of the present invention to provide a plasma processing apparatus that can easily and inexpensively produce a reaction vessel.

Another object of the present invention is to provide a plasma processing method capable of performing plasma processing substantially uniformly in the width direction without unevenness.

[0010]

A plasma processing apparatus according to a first aspect of the present invention includes a cylindrical reaction vessel 1 and a pair of electrodes 2 and 3, and the reaction vessel 1 contains an inert gas or an inert gas. A glow-like discharge is generated under atmospheric pressure by introducing a plasma-generating gas composed of a mixture of gas and a reaction gas and applying an AC electric field to the reaction vessel 1 at a position corresponding to between the electrodes 2 and 3. The plasma P is generated from the plasma generation gas, and the plasma P is
A plasma processing apparatus for supplying plasma P generated in the reaction vessel 1 to the object to be treated 7 in the form of a jet in the reaction vessel 1. At least one of the electrodes 2 and 3 is provided outside the reaction vessel 1, and a sheet member 6 made of a conductive material is interposed between the electrodes 2 and 3 provided outside the reaction vessel 1 and the reaction vessel 1. Is provided in close contact with the outer surface of the reaction vessel 1.

A plasma processing apparatus according to a second aspect of the present invention is characterized in that, in addition to the configuration of the first aspect, both electrodes 2 and 3 are provided outside the reaction vessel 1. .

According to a third aspect of the present invention, there is provided a plasma processing apparatus according to the first or second aspect, further comprising:
On the outer surface of the reaction vessel 1.

A plasma processing apparatus according to a fourth aspect of the present invention is characterized in that, in addition to any one of the first to third aspects, the outlet 4 is formed wide.

A plasma processing apparatus according to a fifth aspect of the present invention is characterized in that, in addition to any one of the first to fourth aspects, the sheet resistance of the sheet member 6 is set to 20 mΩ or less. is there.

According to a sixth aspect of the present invention, there is provided a plasma processing apparatus according to any one of the first to fifth aspects, wherein the thickness of the sheet member 6 is controlled by adjusting the frequency of the high frequency voltage applied to the electrodes 2 and 3. Characterized by being formed to have a skin depth equal to or greater than the skin depth.

According to a seventh aspect of the present invention, there is provided a plasma processing method according to any one of the first to sixth aspects, wherein the object to be processed 7 is disposed below the outlet 4 of the plasma processing apparatus. It is characterized in that the plasma P is blown out and supplied to the workpiece 7.

[0017]

Embodiments of the present invention will be described below.

FIG. 1 shows an example of the plasma processing apparatus of the present invention. The plasma processing apparatus is formed by providing a pair of electrodes 2 and 3 in contact with each other over the entire outer circumference of the reaction vessel 1 and arranging the electrodes 2 and 3 so as to face each other up and down. A discharge space 15 is formed inside the reaction vessel 1 at a position corresponding to between the electrode 2 and the electrode 3. One of the pair of electrodes 2 and 3 is formed as a high-voltage electrode to which a high voltage is applied by being connected to a power supply 18 for generating a high frequency, and the other electrode 3 is formed as a ground electrode to be grounded. Have been.

The reaction vessel 1 is formed of an insulating material (dielectric material) having a high melting point. The dielectric constant of the insulating material constituting the reaction vessel 1 is an important factor in lowering the temperature of the plasma in the discharge space 15, and is preferably 2000 or less. Specifically, as an insulating material, quartz, alumina,
Vitreous materials such as yttria partially stabilized zirconium and ceramic materials can be exemplified.

As shown in FIGS. 2 (a), 2 (b) and 2 (c), the reaction vessel 1 has a pair of side walls 1a facing each other side by side in the thickness direction (the thickness direction is indicated by an arrow B). A pair of side walls 1b facing each other side by side in the width direction (the width direction is indicated by an arrow A), and a rectangular (rectangular when viewed from the bottom) bottom 1c constituting the lower surface of the reaction vessel 1 are formed into a bottomed rectangular cylindrical shape. Is formed. The upper surface of the reaction vessel 1 is open almost entirely as a gas inlet 16 and the lower surface of the reaction vessel 1, which is the outer surface of the bottom 1c, is formed as a substantially flat surface.
Then, as shown in FIG. 2B, a long and wide outlet 4 is formed in a direction parallel to the longitudinal direction (width direction) of the reaction vessel 1 at a substantially central portion of the lower surface of the reaction vessel 1 in the thickness direction. Have been. The outlet 4 has a slit shape and penetrates through the bottom 1 c of the reaction vessel 1 and communicates with the discharge space 15 inside the reaction vessel 1.

The reaction vessel 1 has a flat shape whose width is much larger than its thickness, and has an inner dimension in the thickness direction (narrow direction) of the reaction vessel 1, that is, the thickness direction of the reaction vessel 1 (thickness direction). It is preferable that the interval between the inner surfaces of the pair of side walls 1a facing each other (in the narrow direction) is 0.1 to 5 mm. By setting the inner size in the thickness direction of the reaction vessel 1 to 0.1 to 5 mm in this manner, the volume of the discharge space 15 becomes relatively small, and the power per unit space in the discharge space 15 can be increased. In other words, the discharge space density in the discharge space 15 can be increased, and the power consumption and gas flow can be reduced.
In addition, the plasma generation efficiency is increased, and the capability of plasma processing can be improved.

If the inner size of the reaction vessel 1 is less than 0.1 mm, the blowing port 4 becomes too small, so that the plasma blowing range is narrowed, and the range in which plasma processing can be performed may be reduced. The strength of the reaction vessel 1 may be reduced. On the other hand, the inner size of the reaction vessel 1 is 5 mm
If it becomes larger, the outlet 4 becomes too large, the flow rate of the jet-like plasma blown out from the outlet 4 becomes small, and the speed of the plasma processing may be reduced, and the volume of the discharge space 15 becomes large. As a result, the input power per unit volume (AC electric field) in the discharge space 15 becomes small, the efficiency of plasma generation is reduced, and the speed of plasma processing may be reduced. The only solution to these problems is to increase the gas flow rate and power. However, as a result, a large amount of gas and power are consumed, and the cost performance may decrease. Therefore, it is preferable that the inner size of the reaction vessel 1 is formed to be 0.1 to 5 mm.

On the outer surface of the reaction vessel 1 (outer surfaces of the side walls 1a and 1b), a sheet member 6 is formed over the entire circumference.
The sheet member 6 is formed of a conductive material,
Specifically, it can be formed of gold, silver, copper, an alloy containing these, or the like. The sheet member 6 is provided in close contact with the outer surface of the reaction vessel 1. The sheet member 6 may be formed into a thin sheet shape with a conductive material and then attached to the outer surface of the reaction vessel 1.
The sheet member 6 may be formed by applying (coating) a conductive material to the outer surface of the sheet member 6. In order to increase the adhesion between the sheet member 6 and the outer surface of the reaction vessel 1, it is preferable to form the sheet member 6 by adhesion.
In forming the sheet member 6 by adhesion, a paste-like conductive material can be provided on the outer surface of the reaction vessel 1 by printing or coating, and the paste-like conductive material can be fired and cured. Alternatively, a sheet material 6 may be formed by plating an outer surface of the reaction vessel 1 with a conductive material. The sheet member 6 is formed as a pair, which is vertically arranged.
This is the part where is arranged.

The sheet resistance of the sheet member 6 is preferably 20 mΩ or less. The sheet resistance of the sheet member 6 is 2
If it is larger than 0 mΩ, resistance loss due to heat generation in the sheet member 6 increases, and a potential distribution occurs in the sheet member 6, which may cause uneven discharge in the discharge space 15 of the reaction vessel 1. The lower the sheet resistance of the sheet member 6 is, the more preferable it is. Therefore, the lower limit is not particularly set, but the sheet resistance of the currently available sheet member 6 is 0.1 mΩ or more. Note that the sheet resistance ρ
_s is used instead of the resistivity ρ of the sample when the sample (the sheet member 6 in the present invention) is a thin film and the thickness is not clear or when evaluating the surface conductivity of the sample, Assuming that the width of the sample is w, the thickness of the sample is d, and the length of the sample is L, the cross-sectional area S of the sample is S = wd. Therefore, the resistance value R of the sample is R = ρ _s × (L / w),
Therefore, it is represented by the equation ρ _s = ρ / d.

The thickness of the sheet member 6 is preferably formed to be equal to or greater than the skin depth corresponding to the frequency of the high-frequency voltage applied to the electrodes 2 and 3. When the thickness of the sheet member 6 is less than the skin depth corresponding to the frequency of the high-frequency voltage to be applied, a voltage drop occurs when a high-frequency current flows through the sheet member 6, and as a result, a power loss occurs at the sheet member 6 portion There is fear.

The skin depth is an index indicating a so-called skin effect in which a high-frequency current flows through a conductor only near the surface of the conductor, and is defined by the following equation (1).

[0027]

(Equation 1)

In the upper part of the reaction vessel 1, a gas homogenization chamber 5 is integrally formed. The gas homogenization chamber 5 is formed in a box shape thicker than the reaction vessel 1, and a gas pipe section 10 provided with a gas supply port 19 is formed on the upper surface of the gas homogenization chamber 5 and protrudes. The lower portion of the uniformizing chamber 5 is formed as a narrowed portion 11 whose thickness becomes smaller toward the lower side. , 1b. Further, a cylindrical flange portion 14 projecting into the gas equalizing chamber 5 is formed at a joint portion of the throttle portion 11,
The upper surface of the flange 14 is opened as a gas inlet 16 of the reaction vessel 1.

The electrode 2 and the electrode 3 have the same shape and are formed in a square shape (square ring) in plan view. That is, an insertion hole 17 penetrating vertically is formed substantially at the center of the electrodes 2 and 3. The size of the insertion hole 17 is
And the shape of the insertion hole 17 in plan view is substantially the same as the outer shape of the reaction vessel 1. Further, the electrode 2 and the electrode 3 are made of a metal material having high thermal conductivity, such as copper, in order to increase the cooling efficiency.
Aluminum, brass, corrosion-resistant stainless steel (SUS
304 etc.). Also, electrodes 2, 3
It is also effective to plate the surface with gold or the like, which has higher corrosion resistance and good propagation of high frequency. Then, by forming the electrodes 2 and 3 in a rectangular shape in plan view, the electrodes 2 and 3 can be arranged over the entire circumference of the reaction vessel 1. 3 and the contact area between the reaction vessel 1 and the contact vessel can be improved,
This facilitates generation of the plasma P.

Then, by inserting the reaction vessel 1 into the insertion hole 17, the electrodes 2, 3
Is attached to the outer periphery of the reaction vessel 1 and the electrodes 2 and 3
Is arranged so as to be in contact with the sheet member 6 formed on the outer peripheral surface (outer surfaces of the side walls 1a and 1b) of the reaction vessel 1 so that the sheet member 6 is disposed between the reaction vessel 1 and the electrodes 2, 3. The power supply 18 for generating an AC electric field is connected to the electrode 2 and the electrode 3 is grounded, whereby the plasma processing apparatus as shown in FIG. 1 can be formed. Here, the electrode 3 to be grounded is located below the electrode 2 to which a high voltage is applied, that is, the electrode 3 is located closer to the outlet 4 than the electrode 2. By arranging the electrode 3 closer to the outlet 4 than the electrode 2 in this way, the electrode 3 is positioned closer to the workpiece to be disposed below the outlet 4 than the electrode 2. That is, the electrode 2 having a high voltage is located farther from the workpiece than the electrode 3, so that arc discharge does not easily fly from the electrode 2 to the workpiece, and the workpiece is damaged by the arc discharge. Can be prevented.

The distance between the electrodes 2 and 3 (the distance between the lower end of the electrode 2 and the upper end of the electrode 3) is preferably set to 3 to 20 mm. If the distance between the electrode 2 and the electrode 3 is less than 3 mm, a short circuit may occur between the electrode 2 and the electrode 3 outside the reaction vessel 1 and no discharge may occur in the discharge space 15. There is a possibility that it becomes difficult to efficiently generate plasma because of the narrowing. On the other hand, if the distance between the electrode 2 and the electrode 3 exceeds 20 mm, it becomes difficult for discharge to occur in the discharge space 15 and it may be difficult to efficiently generate plasma. In addition, you may make it cool the electrodes 2 and 3 with a refrigerant | coolant.

In the plasma processing apparatus formed as described above, an inert gas (rare gas) is used as a plasma generating gas.
Alternatively, a mixed gas of an inert gas and a reaction gas is used. As the inert gas, helium, argon, neon, krypton, or the like can be used, but it is preferable to use argon or helium in consideration of discharge stability and economy. The type of the reaction gas can be arbitrarily selected depending on the content of the treatment. For example, when performing cleaning of an organic substance present on the surface of the object to be processed, stripping of a resist, etching of an organic film, etc., oxygen, air,
It is preferable to use an oxidizing gas such as CO ₂ and N ₂ O.
In addition, a fluorine-based gas such as CF ₄ can be appropriately used as a reaction gas, and it is effective to use the fluorine-based gas when etching silicon or the like. In the case of reducing a metal oxide, a reducing gas such as hydrogen or ammonia can be used. The amount of the reaction gas added is 10% by weight or less, preferably 0.1 to 5% by weight, based on the total amount of the inert gas. If the addition amount of the reaction gas is less than 0.1% by weight, the treatment effect may be reduced, and if the addition amount of the reaction gas exceeds 10% by weight, the discharge may be unstable.

In performing plasma processing using the plasma processing apparatus formed as described above, first, as shown by an arrow, a plasma generating gas is introduced into the gas homogenizing chamber 5 from the gas supply port 19. The gas for plasma generation is caused to flow downstream to the gas inlet 16, and thereafter, the gas
A gas for plasma generation is introduced into the reaction vessel 1 from above, and the gas for plasma generation is flowed from the top to the bottom inside the reaction vessel 1, and a high frequency voltage is applied to the electrode 2 from the power source 18, and the electrode 2 and the electrode A high-frequency AC electric field is applied to the discharge space 15 during the period 3. The glow-like discharge is generated in the discharge space 15 under the atmospheric pressure by applying the AC electric field, and the plasma for generating the plasma is generated by the glow-like discharge to generate the plasma containing the plasma active species. A jet-shaped plasma P having a width like a curtain is continuously discharged downward, and the plasma P is blown onto the surface of the processing target 7 arranged below the outlet 4. In this way, the plasma processing of the processing object P can be performed. Further, in order to perform the plasma processing on the entire surface of the substrate 7 which is a flat substrate and which is to be processed, the substrate or the plasma processing apparatus is moved in a direction orthogonal to the longitudinal direction of the blowing port 4 while blowing the plasma P. Let
The plasma P is scanned and sprayed on the entire surface of the substrate. Furthermore, the plasma processing apparatus or the workpiece 7
Is vibrated in a direction perpendicular to the moving direction of the processing target 7, whereby the plasma P is repeatedly sprayed on the processing target 7, so that the uniformity of the plasma processing can be improved.

In the present invention, the frequency of the AC electric field applied to the discharge space 15 is preferably set to 1 kHz to 200 MHz. If the AC frequency is less than 1 kHz, the discharge in the discharge space 15 cannot be stabilized, and the plasma processing may not be performed efficiently. If the AC frequency exceeds 200 MHz, the temperature of the plasma in the discharge space 15 rises remarkably, and the life of the reaction vessel 1, the electrode 2, and the electrode 3 may be shortened, and the plasma processing apparatus becomes complicated. And there is a fear that the size becomes large. In the present invention, the discharge space 15
The density of the applied power applied to is 20 to 3500 W / cm
^It is preferably set to ³ . If the density of the applied power applied to the discharge space 15 is less than 20 W / cm ³ , plasma cannot be sufficiently generated, and conversely, the density of the applied power applied to the discharge space 15 becomes 3500 W / c.
Beyond m ^3, it may be impossible to obtain a stable discharge. The density of the applied power (W / cm ³ )
(Applied power / discharge space volume).

In this embodiment, a sheet member 6 made of a conductive material is interposed between the electrodes 2, 3 provided outside the reaction vessel 1 and the outer surface of the reaction vessel 1, and the sheet member 6 is connected to the reaction vessel 1. Because it is provided in close contact with the outer surface of 1,
The high-frequency power (AC power) supplied from the electrodes 2 and 3 can be uniformly applied to the reaction vessel 1 through the sheet member 6, and the discharge space 15 inside the reaction vessel 1 is less sparse and dense in the discharge direction. Thus, the plasma processing can be performed almost uniformly without unevenness. In addition, there is no need to perform polishing or the like after heat welding when manufacturing the reaction vessel 1, and the reaction vessel 1 can be easily and inexpensively manufactured.

The reaction vessel 1 is formed such that the lines of electric force are formed along the inner surfaces of the side walls 1a and 1b of the reaction vessel 1.
The electrode 2 and the electrode 3 are arranged so as not to face each other, so that lines of electric force are less likely to be generated in the vertical direction of the inner surface of the reaction container 1, and the deterioration of the reaction container 1 due to the lines of electric force can be reduced. This makes it difficult for the constituent material to jump out from the inner surfaces of the side walls 1a and 1b of the container 1, thereby reducing contamination of the processing object 7 with impurities.

In the above-described embodiment, since the outlet 4 for blowing the jet-shaped plasma having a width is formed on the lower surface of the reaction vessel 1, the plasma having a width like a curtain is blown out. By moving the substrate or the plasma processing apparatus in a direction perpendicular to the longitudinal direction of the blow-out port 4 while blowing the plasma from the base 4, and scanning and blowing the plasma over the entire surface of the substrate, the processing to be performed is smaller than that in which the spot-like plasma is blown. A large area of an object can be plasma-processed at a time, and the processing time can be reduced when processing the entire surface of a substrate such as a BGA substrate.

Further, in the above embodiment, since both the electrodes 2 and 3 for applying an AC electric field to the discharge space 15 are provided outside the reaction vessel 1, both the electrodes 2 and 3 are plasma P The electrode 2 and the electrode 3 can be prevented from being sputtered by the reaction gas while being not directly exposed to the plasma and being prevented from being sputtered by the plasma P. The plasma P is not damaged and the life can be extended. Moreover, since no impurities are generated by sputtering or corrosion, the object 7 can be prevented from being contaminated by the impurities even when used for a long time. Note that one electrode 2 may be provided inside the reaction vessel 1 and the other electrode 3 may be provided outside the reaction vessel 1.

In the above-described embodiment, the electrodes 2 and 3 are arranged so as to face each other in the direction of introduction of the plasma generating gas, that is, the electrodes 2 and 3 are arranged vertically and opposed to each other. The direction of the AC electric field (the direction of the electric lines of force) generated in the discharge space 15 can be substantially matched with the flow direction of the plasma generating gas and the plasma P.
The active species of the plasma P can be efficiently generated, and the size of the discharge space 15 can be easily changed by changing the distance between the electrode 2 and the electrode 3. Can be easily adjusted.

Further, by supplying the gas for plasma generation to the reaction vessel 1 by passing the gas through the gas homogenization chamber 5, the gas for plasma generation is agitated by the flange portion 14 and is not biased to a part in the reaction vessel 1. Reaction vessel 1
Can be supplied at a uniform concentration throughout the inside, and a uniform plasma P can be efficiently generated.
Processing unevenness can be reduced.

The glow discharge plasma generating electrode formed by interposing a metal mesh between the electrode and the dielectric is disclosed in
It is disclosed in 199995. However, in this electrode, a wire mesh is used as a member corresponding to the sheet member 6 of the present invention, and the dielectric and the wire mesh are in line contact with each other. It does not make it. Therefore, in Japanese Patent Application Laid-Open No. 6-119995, arc discharge is apt to occur and uniform plasma is hardly generated.

[0042]

The present invention will be described below in detail with reference to examples.

Example A plasma processing apparatus having the structure shown in FIG. 1 was formed. As the reaction vessel 1, the one made of quartz glass shown in FIG. 2 was used, and the inner dimension in the width direction was 55 m.
m, the inner dimension in the thickness direction is 1 mm, the outer dimension in the width direction is 57 mm, and the outer dimension in the thickness direction is 3
mm. The size of the outlet 4 is the same as the above inner size (55 mm × 1 mm).
The electrodes 2, 3 arranged above and below the outlet 4 are made of copper. Further, a sheet member 6 was interposed between the outer peripheral surface of the reaction vessel 1 and the inner peripheral surfaces of the electrodes 2 and 3. Sheet member 6
Is formed to a thickness of 50 μm.
Has a sheet resistance of 5 mΩ. The sheet member 6 is made of a conductive material (“MICRO-LOCKPd / Ag CONDUCTOR” manufactured by ES L Japan Co., Ltd.).
9601 ", a palladium-silver paste) is printed on the outer surface of the reaction container 1 by screen printing, and thereafter, a conductive material is baked to form the conductive material.

As the object 7 to be processed, a silicon substrate coated with a negative resist of 1 μm was used. The gas for plasma generation was 2 liters / min of helium and 1 liter of argon.
A mixture obtained by mixing 0 liter / minute and oxygen at a rate of 0.4 liter / minute was supplied to the reaction vessel 1 by flowing. Then, a high-frequency electric field of 13.56 MHz at 700 W is applied to the discharge space 15 to generate plasma P, which is blown out from the outlet 4 in a wide jet shape and supplied to the surface of the processing object 7 to perform plasma processing (resist). Etching). The skin depth at this time is 20 μm, and the sheet member 6 is formed thicker than this skin depth.

(Comparative Example) A plasma processing apparatus was formed in the same manner as in the embodiment except that the sheet member 6 was not provided, and the workpiece 7 was subjected to plasma processing in the same manner as in the embodiment.

FIG. 3 is a graph showing the relationship between the position in the width direction of the reaction vessel 1 and the plasma processing performance (etching depth) in each of the example and the comparative example. In the example, the plasma processing was performed almost uniformly at any position, whereas in the comparative example, there were places where the plasma processing was insufficient and places where the plasma processing was performed excessively. The variation (dispersion / average × 100) of the plasma processing of the example was about 6%, whereas the variation of the plasma processing of the comparative example was about 25%, and the example was better than the comparative example. Also, the variation in the plasma treatment was significantly small.

It should be noted that even when gold having a thickness of 50 μm is formed as a sheet member 6 on the outer surface of the reaction vessel 1 by plating instead of the palladium-silver paste, uniform plasma processing is realized in the same manner as in the above embodiment. We were able to.

[0048]

As described above, the invention of claim 1 of the present invention comprises a cylindrical reaction vessel and a pair of electrodes, and the reaction vessel contains an inert gas or a mixed gas of an inert gas and a reaction gas. By introducing an AC electric field into the reaction vessel at a position corresponding to between the electrodes, a glow-like discharge is generated under atmospheric pressure to generate plasma from the plasma generating gas. A plasma processing apparatus for supplying the plasma to the surface of the workpiece,
An outlet for ejecting plasma generated in the reaction vessel in a jet shape toward the object to be processed is formed in the reaction vessel, at least one of a pair of electrodes is provided outside the reaction vessel, and outside the reaction vessel. Since a sheet member made of a conductive material is interposed between the provided electrode and the reaction container and the sheet member is provided in close contact with the outer surface of the reaction container, the sheet member is applied to the electrode provided outside the reaction container by the interposition of the sheet member. AC power can be uniformly supplied to the reaction vessel, and the discharge in the reaction vessel can be performed almost uniformly without unevenness, and plasma processing can be performed on the object to be processed without unevenness. The plasma processing in the width direction can be performed almost uniformly without unevenness. In addition, there is no need to perform polishing or the like after heat welding when producing the reaction vessel, and the reaction vessel can be produced simply and inexpensively.

According to the invention of claim 2 of the present invention, since both electrodes are provided outside the reaction vessel, both electrodes are not directly exposed to plasma so that they are not subjected to sputtering by plasma. Can be done,
Both electrodes can be prevented from being corroded by the reaction gas, and the electrodes can be prevented from being damaged by the plasma and the life can be extended. In addition, since no impurities are generated by sputtering or corrosion, the object to be processed can be prevented from being contaminated by the impurities even when used for a long time.

According to the invention of claim 3 of the present invention, since the sheet member is attached to the outer surface of the reaction vessel, the adhesion of the sheet member to the reaction vessel is increased, and the electrode provided outside the reaction vessel and the reaction vessel. The plasma treatment can be performed almost uniformly without unevenness in the discharge in the reaction vessel, and the plasma treatment can be carried out almost uniformly. The processing can be performed almost uniformly without unevenness.

According to the invention of claim 4 of the present invention, since the outlet is formed wide, a wide plasma can be supplied to the object to be processed, and the plasma processing in the width direction is performed almost uniformly without unevenness. In addition, a large area of the object can be plasma-treated in a short time.

According to the invention of claim 5 of the present invention, since the sheet resistance of the sheet member is set to 20 mΩ or less, the resistance loss due to heat generation in the sheet member can be reduced, and a potential distribution is generated in the sheet member. This makes it possible to prevent the occurrence of unevenness in the discharge inside the reaction vessel due to the difficulty.

According to the invention of claim 6 of the present invention, the thickness of the sheet member is formed to be equal to or greater than the skin depth corresponding to the frequency of the high-frequency voltage applied to the electrode, so that no power loss occurs in the sheet member. It is possible to increase the plasma generation efficiency.

Further, the invention of claim 7 of the present invention is directed to claim 1
7. An object to be processed is arranged below the outlet of the plasma processing apparatus according to any one of the above items 6 to 6, and plasma is blown out from the outlet and supplied to the object to be processed. AC power applied to the electrode can be uniformly supplied to the reaction vessel, and the discharge in the reaction vessel can be performed without unevenness and plasma processing can be performed almost uniformly on the workpiece. In particular, plasma processing in the width direction can be performed almost uniformly without unevenness. In addition, there is no need to perform polishing or the like after heat welding when producing the reaction vessel, and the reaction vessel can be produced simply and inexpensively.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an embodiment of the present invention.

FIG. 2 shows a reaction container of the above, (a) is a front view,
(B) is a side view, and (c) is a bottom view.

FIG. 3 is a graph showing plasma processing performance of an example and a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction container 2 Electrode 3 Electrode 4 Outlet 6 Sheet member 7 Workpiece P Plasma

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keiichi Yamazaki 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Kazuya Kitayama 1048 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Works (72) Inventor Masaharu Yasuda 1048 Kadoma, Kadoma, Osaka Pref. Matsushita Electric Works, Ltd. (72) Inventor Yoshiyuki Nakazono 1048 Kadoma, Kazuma, Kadoma, Osaka Pref. DA16 DB06 DD01 DD08 DK03 DM06 DM08 DM09 DM28 DM35 DN01 5F004 AA01 AA14 BA03 BA06 BB13 BB29 BD01 CA02 DA22 DA23 DA26 DB26

Claims (7)

[Claims] An apparatus comprising: a tubular reaction vessel and a pair of electrodes;
By introducing an inert gas or a plasma-generating gas consisting of a mixture of an inert gas and a reaction gas into the reaction vessel and applying an AC electric field to the reaction vessel at a position corresponding to between the electrodes, the reaction vessel is maintained at atmospheric pressure. A plasma processing apparatus that generates a glow-like discharge to generate plasma from a plasma generating gas and supplies the plasma to the surface of the processing object, and the plasma generated in the reaction vessel is applied to the processing object. An outlet for jetting toward the jet is formed in the reaction container, at least one of the pair of electrodes is provided outside the reaction container, and a conductive material is provided between the electrode and the reaction container provided outside the reaction container. A plasma processing apparatus comprising a sheet member interposed therebetween and a sheet member closely attached to an outer surface of the reaction vessel. 2. The plasma processing apparatus according to claim 1, wherein both electrodes are provided outside the reaction vessel. 3. The plasma processing apparatus according to claim 1, wherein a sheet member is attached to an outer surface of the reaction vessel. 4. The plasma processing apparatus according to claim 1, wherein the outlet is formed wide. 5. The plasma processing apparatus according to claim 1, wherein the sheet resistance of the sheet member is set to 20 mΩ or less. 6. The plasma processing apparatus according to claim 1, wherein the thickness of the sheet member is equal to or greater than the skin depth corresponding to the frequency of the high-frequency voltage applied to the electrode. . 7. An object to be processed is arranged below an outlet of the plasma processing apparatus according to claim 1;
A plasma processing method, characterized in that plasma processing is performed by blowing out plasma from an outlet and supplying the plasma to an object to be processed.