JP5317162B2 - Plasma apparatus, plasma processing apparatus and plasma processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device efficiently generating uniform and high-density plasma over a wide range without contaminating a processing object. <P>SOLUTION: The device includes a wave-guide section 5 of a rectangular type mounted on a container to propagate microwaves of a free space wavelength &lambda;, a slot antenna 10 comprising a plurality of rectangular slots 12 formed on a wall of the wave-guide section 5 in a longitudinal direction of the wall at intervals of 1/2 a guide wavelength &lambda;g and a dielectric panel 11 disposed in contact with an outer surface of the wall having the slot antenna 10 to cover the slot antenna 10. The plurality of slots 12 (a) are alternately arranged with a longitudinal axis of the wall interposed, (b) are constant in distance from a central axis, (c) when n denotes the number of the plurality of slots 12 and m denotes the number obtained by dividing n&times;&lambda;g/2 by &lambda;/2, satisfy m-1&lt;n&lt;m and (d) are formed such that the impedance of the wave-guide part 5 is almost equal to the characteristic impedance or the impedance obtained when a second wave-guide 5 has no slot antenna 10. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a plasma apparatus that generates plasma using microwaves, a plasma processing apparatus that performs surface treatment on an object using the plasma apparatus, and a method thereof.

  Functional plastic films imparted with various functions by forming an inorganic thin film on the surface of the plastic film are used in various fields. Specific examples of the functional plastic film include a transparent conductive film used for a display, a solar cell, and the like, a flexible substrate used for home appliances, electrical equipment, and the like. Functional plastic films are also used for chemical and gas piping.

  Functional plastic films are often used in places where they are bent or stretched by taking advantage of their features. When the functional plastic film is bent, the inorganic thin film formed on the surface may be peeled off. In particular, under conditions of use where bending and stretching are repeated or temperature changes are large, the inorganic thin film is easily peeled off, which greatly affects the service life of the product. Therefore, it is a practically important issue to improve the adhesion between the inorganic thin film and the plastic film and make the inorganic thin film difficult to peel off.

  Therefore, in order to improve the adhesion, a technique for treating the surface of a plastic film forming an inorganic thin film has been proposed. As one of the surface treatment techniques, there is a technique of irradiating the surface of a plastic film with plasma (for example, see Patent Documents 1 to 3).

  In addition, the range of use of functional plastic films has expanded, and demand for large-area functional plastic films has increased. Therefore, in order to perform surface treatment on a large-area plastic film, techniques for generating uniform and high-density plasma over a wide range have been proposed (for example, Patent Documents 4 and 5).

The plasma processing apparatus described in Patent Document 4 includes a rectangular waveguide, a plurality of slots that are provided in the rectangular waveguide, and constitute a waveguide antenna, and a container, and is emitted from the slot into the container. Plasma is generated by electromagnetic waves and plasma treatment is performed. A plurality of rectangular waveguides are provided, and the rectangular waveguides are arranged in contact with each other. Further, the slots are uniformly distributed over the entire area to be plasma processed. Thus, a large area substrate (plastic film) is processed with a uniform plasma density. Patent Document 5 also describes a plasma processing apparatus having a generally similar configuration.
Japanese Patent Laid-Open No. 63-120163 JP 11-354292 A JP 2002-280196 A JP 2004-200390 A Japanese Patent Laid-Open No. 2005-268652

  However, there is room for reducing the propagation loss of the microwave propagating in the waveguide in the conventional technology. Further, in the conventional technique, the plasma generated from the slot is not necessarily uniform, and there is a problem that the plasma irradiated to the plastic film is also non-uniform. An object of this invention is to provide the apparatus which can generate | occur | produce a uniform and high-density plasma efficiently over a wide range, without contaminating a process target object with the material of a plasma electrode.

In order to achieve this object, the plasma apparatus according to the present invention provides
A plasma device for generating microwave plasma in a container,
A wall portion that forms a rectangular cross-sectional shape, a waveguide portion that is attached to the container and transmits microwaves having a free-space wavelength λ,
A slot antenna composed of a plurality of rectangular slots formed in the longitudinal direction of the waveguide section at intervals of ½ of the guide wavelength λg on the wall section;
A dielectric plate that is provided in contact with the outer surface of the wall portion having the slot antenna and covers the slot antenna;
The plurality of slots forming the slot antenna are
a) Alternatingly arranged across the central axis in the longitudinal direction of the wall portion having the slot antenna,
b) the distance from the central axis is constant;
c) When the number of the plurality of slots is n and the number obtained by dividing n × λg / 2 by λ / 2 is m, m-1 <n <m is satisfied,
d) The conditions of a) to d) that the impedance of the waveguide section viewed from the microwave power supply side is substantially equal to the characteristic impedance of the waveguide section viewed from the opposite power supply side are satisfied.
In addition, the present invention is not limited to such a plasma apparatus, but includes a plasma processing apparatus that includes the same configuration as the plasma apparatus and performs surface treatment on the object, and plasma processing that processes the object using the plasma apparatus Also includes a method.

  According to the present invention, since plasma is generated without using the electrode plate, the object to be treated is not contaminated by the material of the electrode plate. Moreover, since the impedance of the waveguide section having the slot antenna as a load from the power supply side matches the characteristic impedance of the waveguide viewed from the power supply side, the microwave power is uniformly distributed from a plurality of slots. Efficiently radiated and high concentration plasma can be generated uniformly. As a result, it becomes possible to irradiate the processing object with plasma substantially uniformly.

(Embodiment 1)
The plasma apparatus is an apparatus that efficiently generates plasma by cooperation of a group of devices connected by a waveguide. For example, as shown in FIG. 1, a plasma processing apparatus 1 that processes the surface of a plastic film. Prepared for. The plasma processing apparatus 1 includes a plasma apparatus 2 that generates microwave plasma, a container 3, and a table 7.

  The container 3 is a container that is filled with a predetermined gas and can maintain the internal pressure within a certain range. The container 3 is connected to an exhaust pump and a gas supply cylinder (not shown). The pressure inside the container 3 may be atmospheric pressure, but is preferably reduced to 5 Pa to 50 Pa. The gas is, for example, argon gas. In addition, in order to improve the effect of surface treatment, gas may be suitably selected according to the kind of plastic film, for example, oxygen gas etc. are mixed. Inside the container 3, a plasma generation unit 13, a plastic film 9, and a table 7 are provided.

  The stand 7 as a support part supports the plastic film 9 (processing object). The plastic film 9 is a plastic film piece cut into a predetermined size. The thickness of the plastic film 9 is preferably a thickness that is flexible and does not easily become wrinkles. The specific thickness of the plastic film 9 is, for example, preferably in the range of 5 to 500 μm, more preferably in the range of 8 to 300 μm, but is not limited to these thicknesses.

  The plastic film 9 is, for example, a film obtained by melting and extruding an organic polymer and then stretching, cooling, heat setting and the like in the longitudinal direction and / or the width direction as necessary. An organic polymer is dissolved in a solvent to make a dope, and the dope is cast on a moving support to form a cast film, and then dried by sending dry air to the cast film. A film obtained by peeling off the cast film and drying it may be mentioned. Organic polymers used as raw materials include polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate, nylon 6, nylon 4, nylon 66, nylon 12, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, wholly aromatic Group polyamide, polyamideimide, polyimide, polyetherimide, polysulfone, polyphenylene sulfide, polyphenylene oxide, triacetyl cellulose, polycarbonate, fluororesin, and the like, but are not limited thereto. These organic polymers may be copolymerized or blended with other organic polymers. Furthermore, additives having known functions such as ultraviolet absorbers, antistatic agents, plasticizers, lubricants, and colorants may be added to the organic polymer. Preferable specific examples include, for example, a biaxially stretched polyethylene terephthalate film (PET film), a biaxially stretched polyethylene naphthalate film (PEN film), a biaxially stretched polyphenylene sulfide film (PPS film), a biaxially stretched nylon 6 film ( NY6 film), biaxially stretched nylon MXD6 film (MXD6 film), biaxially stretched polypropylene film (PP film), biaxially stretched wholly aromatic polyamide film (aramid film), polyimide film (PI film) and the like. Such a plastic film may be formed of an organic polymer single layer or may be formed of multiple layers. For example, a plastic film formed by using an organic polymer with a plasticizer in the inner layer and a plasticizer removed on the surface layer, or a plastic film in which different organic polymers are laminated may be used. The surface of the plastic film may be coated. The processing object may be other than a plastic film, and may be, for example, glass, ceramic, paper, fiber, cloth, nonwoven fabric, metal, or the like.

  The plasma apparatus 2 includes a microwave power source 15, an isolator 17, a power meter 19, a matching unit 21, a plasma generation unit 13 that generates plasma, a first waveguide 4 </ b> A that connects them, and a tapered connection tube. 4B and a joint 4C.

  The microwave power source 15 outputs a microwave having a free space wavelength λ. The microwave output from the microwave power supply 15 is usually in any of a frequency band from 300 MHz to 100 GHz, and for example, 915 MHz or 2.45 GHz is often used for industrial use.

  The isolator 17 passes the microwave only in the direction from the microwave power source 15 toward the plasma generation unit 13 (incident direction, the direction indicated by the arrow parallel to the second waveguide 5 in FIGS. 1 and 2) to generate plasma. The microwave is not passed in the direction (reflection direction) from the unit 13 toward the microwave power source 15. As a result, the microwave reflected from the plasma generator 13 is prevented from returning to the microwave power source 15, and the microwave power source 15 is protected.

  The power meter 19 measures the power of the microwave propagating in each of the incident direction and the reflection direction.

  The matching unit 21 performs impedance matching between the power supply side and load side waveguides connected thereto. That is, the matching unit 21 matches the impedance of the waveguide connected from the device toward the microwave power supply 15 with the impedance of the waveguide connected from the device toward the plasma generator 3. Thereby, the reflection of the microwave is eliminated or reduced, and the reflected power of the microwave returning to the reflection direction can be eliminated or reduced. Therefore, the propagation efficiency of microwaves can be improved.

  The first waveguide 4A is a rectangular waveguide that transmits a microwave supplied from the microwave power source 15. The first waveguide 4A includes the microwave power source 15, the isolator 17, the power meter 19, and the matching unit 21 in order. Connecting. In addition, the tapered connecting tube 4B has a rectangular cross-sectional shape that connects the first waveguide 4A on the plasma generating unit 13 side connected to the matching unit 21 and the plasma generating unit 13 in a microwave transmission direction. It is a waveguide that changes to The first waveguide 4A and the tapered connecting tube 4B are connected by a flange joint (not shown). The joint portion 4C is a portion that connects the tapered connecting tube 4B and the plasma generating portion 13, and is, for example, a portion that is connected by a flange joint.

  As shown in the plan view of FIG. 2 and the side sectional view of FIG. 3, the plasma generator 13 is a part that is attached to the container 3 and generates plasma in the container 3, and is a second waveguide ( Waveguide section) 5, slot antenna 10, and dielectric plate 11. In the embodiment, an example in which the plasma generator 13 is mounted on the upper portion of the container 3 will be described. However, the plasma generation unit 13 may be mounted in the container 3.

The second waveguide 5 is connected to the first waveguide 4A by a tapered connecting tube 4B so that the microwave can be propagated with as little propagation loss as possible. The second waveguide 5 and the first waveguide 4A are connected so that the reflection at the joint 4C can be reduced as much as possible and the microwave can be propagated with a small propagation loss, as will be described later. The taper connection pipe 4B may be connected using a different method or a different method. The second waveguide 5 is attached to the upper part of the container 3. The 2nd waveguide 5 is a rectangular waveguide, Comprising: It has a wall part which forms a rectangular cross-sectional shape. It is known that the guide wavelength λg is 1 / λg ² = 1 / λ ² −1 / λc ^{2 where} the cutoff wavelength is λc. Here, when the height of the second waveguide 5 which is a rectangular waveguide is a and the width is b, the cutoff wavelength λc in the TEmn mode is expressed by Equation 1. Therefore, the guide wavelength λg is determined by the frequency of the microwave supplied by the microwave power supply 15 and the cross-sectional shape of the second waveguide 5.

  The slot antenna 10 is provided on the wall portion of the second waveguide 5 that faces the table 7 and is formed in the longitudinal direction of the second waveguide 5 at intervals of ½ of the guide wavelength λg. It consists of a plurality of rectangular slots 12. Details of the slot arrangement will be described later with reference to FIG.

The dielectric plate 11 is provided in contact with the outer surface of the wall portion having the slot antenna 10 and covers the slot antenna 10. Dielectric plate 11 is in contact with the outer surface of the wall portion having slot antenna 10 and has a mounting surface that covers slot antenna 10 and a plasma generation surface that faces the mounting surface. The thickness of the dielectric plate 11 is preferably not more than a quarter of the wavelength λ of the microwave. The material of the dielectric plate 11 is preferably a material having a low dielectric loss of microwaves and heat resistance, such as quartz (SiO ₂ ), alumina (Al ₂ O ₃ ) and the like.

  FIG. 4 is a view for explaining the arrangement of the plurality of slots 12 in the slot antenna 10 shown in FIGS. 2 and 3, and shows a state where the waveguide unit 5 having the slot antenna is turned upside down. The arrows in FIG. 4 indicate the microwave transmission direction, that is, the incident direction. Further, the second waveguide 5 has a rectangular cross-section hollow of width a and height b, and the wall thickness is t.

  The plurality of slots 12 in FIG. 4 is an example of the plurality of slots 12 in the TE10 mode, and is formed in two alternate rows across the long axis 23 of the wall portion having the slot antenna 10, and the second waveguide 6 shows an example in which six slots from the first slot 12 closest to the end of 5 to the sixth slot 12 are formed along the long axis 23 in order. Each slot 12 has an elongated rectangular shape with a length in the long side direction of l and a length in the short side direction of w. The long side direction of the slot 12 is provided in parallel with the long axis 23, and the center axis 25 in the long side direction of the slot 12 has a constant distance X1 from the long axis 23.

  The center in the long side direction of the first slot 12 is provided at a position where the guide wavelength is 3λg / 4 from the end of the second waveguide 5. When the second waveguide 5 is viewed in a direction parallel to the long axis 23, the interval between the slots 12 is half of the guide wavelength λg (λg / 2). In addition, when the second waveguide 5 is viewed in a direction perpendicular to the long axis 23, the length of the portion where the slot 12 is not formed is d. The center of the first slot 12 in the long side direction may be provided at a position where the inner waveguide wavelength is 3λg / 4 + n · λg / 2 (n: natural number) from the end of the second waveguide 5.

The slot width is narrow (2 log ₁₀ (l / w) >> 1), the slot circumference is near the first resonance (l + w≈λ / 2), the waveguide is a perfect conductor and infinitely thin (t≈0) Under the idealized condition, the equivalent conductance g of one slot normalized by the characteristic impedance of the second waveguide 5 is known to be expressed by (Equation 2) (" Microwave Antenna Theory and Design "edited by Samuel Silver, published by Boston Technical Lithographers, Inc. 1963).

  When the number of slots is n, by forming the slots so as to satisfy n · g = 1 (Equation 3), the impedance of the second waveguide 5 viewed from the microwave power source side is the second conductivity. It matches with the characteristic impedance of the second waveguide 5 when the wave tube 5 does not have the slot antenna 10. That is, when a waveguide having the same shape as that of the second waveguide 5 and having no slot antenna is joined to the plasma generation unit 13, the impedance when the microwave power source side is seen at the joined portion and the plasma generation unit 13 are The impedance seen from the load side is almost equal. Therefore, by forming the slot so as to satisfy the above (Equation 3), reflection at the input end of the plasma generation unit 13 is removed or reduced, and microwaves can be supplied efficiently. Further, when the impedance is matched, the output of the microwaves emitted from each slot becomes almost equal, and it becomes possible to generate a uniform plasma. When the waveguide connected from the junction 4C to the microwave power source is the first waveguide 4A having a cross-sectional shape different from that of the second waveguide 5, the characteristic impedance of both is different. Microwave reflection occurs at the joint. As one method of reducing this reflection, a method of providing a tapered connecting tube 4B having a rectangular cross section that smoothly connects the first waveguide portion 4A and the second waveguide 5 is effective. When the length of the tapered connecting tube 4B is made several times longer than the free space wavelength, the impedance of the tapered connecting portion 4B is changed from the characteristic impedance of the first waveguide 4A to the characteristic impedance of the second waveguide 5. Therefore, the reflection at the joint 4C can be reduced to a level that can be ignored in practice.

ｄは、スロットが存在しない間隔であるため、できるだけ小さい方が好ましい。ｄを小さくすることによって、第２導波管５の壁部の全体にマイクロ波を出力できるため、プラズマ発生部１３は均一なプラズマを発生することが可能になる。インピーダンスを整合しながら、できるだけｄを小さくするには、プラズマを発生させる領域長Ｌ（＝ｎ・λｇ／２）をλ／２で除した数ｎ´を越えないもっとも近い整数ｎでＬを除した長さの２倍をλｇに設定するとよい。すなわち、スロットの数をｎ、ｎ×λｇ／２をλ／２で除して得られる数をｍとした場合、ｍ−１＜ｎ＜ｍを満たす場合に、インピーダンスを整合しながら、ｄを小さくすることができる。 D is expressed by Equation 4.

Since d is an interval at which no slot exists, it is preferably as small as possible. By reducing d, microwaves can be output to the entire wall portion of the second waveguide 5, so that the plasma generator 13 can generate uniform plasma. In order to make d as small as possible while matching the impedance, L is divided by the nearest integer n not exceeding n ′ obtained by dividing the region length L (= n · λg / 2) for generating plasma by λ / 2. It is preferable to set λg to twice the length. That is, when the number of slots is n, and the number obtained by dividing n × λg / 2 by λ / 2 is m, d is set while matching impedance when m−1 <n <m is satisfied. Can be small.

  FIG. 5 shows a specific example that satisfies the above-described conditions of reducing the interval d where no slot exists and matching the impedance in the central axis direction of the wall portion having the slot of the waveguide. The example shown in FIG. 5 is an example in the case of 2.45 GHz, TE10 mode, where a = 150 mm, Xl = 48 mm (2 · Xl = 96 mm), w = 1 mm, l = 60 mm, and d = 7 mm. This is only one specific example, and the present invention is of course not limited thereto.

  With such a configuration, microwaves are supplied from the microwave power source 15. The microwave propagates through the first waveguide 4 </ b> A and the tapered connecting tube 4 </ b> B and propagates to the plasma generating unit 13 attached to the container 3 through the connecting unit 4 </ b> C. The microwave propagates through the container 3 through the slot 12 and the dielectric plate 11, and ionizes the gas to generate plasma. When the microwave power is low, the plasma is thin, and the microwave propagates as a volume wave in the vacuum vessel. When the power increases and the plasma density exceeds the cut-off density, the microwave is reflected by the plasma surface and becomes a surface wave that propagates along the surface of the dielectric plate. Electrons are accelerated by this strong electric field and discharge occurs. Occurs and plasma is maintained. The generated high density plasma irradiates the surface of the plastic film 9. In this way, the plastic film 9 is surface-treated.

(Embodiment 2)
FIG. 6 is a diagram showing the vicinity of the slot antenna 10 of the plasma generating unit 13 according to Embodiment 2 of the present invention. The plasma generation unit 13 in this figure is a perspective view from below showing the container 3 of the plasma apparatus according to Embodiment 2 by cutting away. The plasma generator 13 according to the second embodiment includes the second waveguide 5, the slot antenna 10, and the dielectric plate 11 as in the first embodiment. Furthermore, as shown in FIG. A plurality of permanent magnets 53 are provided in the vicinity of the plasma generation surface of the plate 11.

  FIG. 6 shows an example in which the permanent magnet 53 is provided in the vicinity of the position facing the vicinity of the slot 12 on the plasma generation surface, but the arrangement of the permanent magnet is not limited to this. The permanent magnet 53 may be provided, for example, so as to be sandwiched between the mounting surface of the dielectric plate 11, that is, the wall portion of the second waveguide 5 having the slot 12 and the dielectric plate 11. It may be provided on both the mounting surface of the plate 11 and the plasma generating surface. Further, the optimum shape, interval, arrangement, and the like of the permanent magnet 53 may be selected as appropriate. In addition, the direction of the magnetic pole of the permanent magnet 53 at the time of installation may be any, and an optimal one may be selected as appropriate. Further, instead of the permanent magnet 53, a magnet such as an electromagnet that can change the direction of the magnetic pole may be arranged, and in this case, the direction of the magnetic pole may be appropriately controlled.

  Thus, by providing the magnet on the dielectric plate, even if plasma is generated under a low pressure, the diffusion of the plasma is suppressed by the magnetic field of the magnet, and the occurrence of collision with the inner wall of the container is reduced. Therefore, it is possible to maintain the plasma at a relatively high concentration even under a low pressure that is about an order of magnitude lower than when there is no magnetic field. This also facilitates the construction of the environment in the container for surface treatment with plasma. Furthermore, as will be described later, after the surface treatment, for example, an inorganic thin film generation treatment is performed. However, since the plastic film is automatically moved from the plasma apparatus to the subsequent processing apparatus, the differential exhaust is little. , Improve practicality. Even in an environment where electron cyclotron resonance occurs, a high-density plasma can be maintained at a low pressure, and the above-described effects can be achieved.

(Embodiment 3)
Next, a thin film forming apparatus using the plasma apparatus described in Embodiment 1 as a plasma source in the thin film forming process will be described. FIG. 7 shows a thin film forming apparatus according to an embodiment of the present invention. The thin film forming apparatus is an apparatus that continuously forms an inorganic thin film on a long plastic film by using a surface treatment by plasma.

  The thin film forming apparatus irradiates plasma on the unwinding unit 31 for continuously unwinding the long plastic film 39 from the unwinding roll 41 through the guide roll 43 to the plasma processing unit 33a, and the plastic film 39. A plasma processing unit (plasma processing apparatus) 33a for surface treatment; a film forming unit 35 for forming an inorganic thin film by sputtering using a sputter target 47 on a plastic film 39 guided by a guide roll 43 and moved by a main roll 45; And a winding unit 37 for winding the plastic film 39 on which the inorganic thin film is formed on the winding roll 49 by the guide roll 43.

  The plasma processing unit 33a includes a container that is a casing of the plasma processing unit 33a. Similarly to the first embodiment, the vacuum for exhausting gas from the container in order to control the pressure and configuration of the gas in the container. A pump and a cylinder for supplying gas are connected (not shown). The plasma processing unit 33a includes a plasma generation unit 13 disposed in a container filled with gas at a predetermined pressure. The plasma generator 13 has a width that is approximately the same as or wider than the width of the plastic film 39, and, like the first embodiment, the second waveguide 5, the slot antenna (10) (not shown), and the dielectric. And a plate (11). The plasma generating surface of the dielectric plate is disposed so as to face the plastic film 39 that moves sequentially. The unwinding device 31 and the guide roll 43 of the film forming unit 35 support the plastic film 39 that moves sequentially as a support portion. Each unit constituting the thin film forming apparatus is a separate unit, and it is preferable that the pressure and gas configuration in each unit be controlled for each unit, but a plurality of units are integrated. May be.

  With the thin film forming apparatus having such a configuration, a long plastic film 39 is sent out from the unwinding roll 41 of the unwinding unit 31, and the surface treatment in the plasma processing unit 33a and the thin film forming process in the film forming unit 35 are made of plastic. After sequentially executing the film 39, the plastic film 39 on which the thin film is formed is wound on the winding roll 49 of the winding unit 37. Thereby, the elongate plastic film in which the inorganic thin film was formed can be manufactured. In addition, since the inorganic thin film is formed on the treated surface after the surface treatment with high-density plasma is performed in the plasma processing unit 33a, it is possible to manufacture a plastic film on which the inorganic thin film with high adhesion is formed. Become.

  In addition, although the film forming unit 35 decided to form a thin film by sputtering, the method of thin film formation is not restricted to this. The thin film in the film forming unit 35 may be formed by a method using other PVD (Physical Vapor Deposition) technology, CVD (Chemical Vapor Deposition) technology, or the like, for example. Also by these methods, it is possible to increase the adhesion between the thin film and the plastic film by forming the thin film on the surface treated by the plasma processing unit according to the present invention.

(Embodiment 4)
As shown in FIG. 8, the thin film forming apparatus of the present embodiment has the same configuration as the thin film forming apparatus of the third embodiment, except for the plasma processing unit 33b. The plasma processing unit 33 b includes a processing roll (supporting part) 51 that sends out a plastic film, a plurality of plasma generation units 13 that are disposed to face the surface of the processing roll 51, and a plastic film that is unwound from the unwinding unit 31. A guide roll 43 that guides 39 to the processing roll 51 and a guide roll 43 that guides the plastic film 39 fed from the processing roll 51 to the film forming unit 35 are provided. The plurality of plasma generation units 13 include a second waveguide 5 and a slot antenna (10) and a dielectric plate (11) (not shown) provided in the second waveguide 5. The plurality of plasma generating units 13 are arranged side by side in the rotation direction of the processing roll 51, and each plasma generating unit 13 has a width approximately equal to or wider than the width of the processing roll 51. The plasma generating surface of the dielectric plate of the plasma generating unit 13 faces the peripheral surface of the processing roll 51 that supports the plastic film 39.

  The distance between the plasma generation surface and the peripheral surface of the processing roll 51 is adjusted to an arbitrary distance within a certain range by a distance adjusting mechanism (not shown) that controls the position of the processing roll 51 and / or the plasma generation unit 13. it can. Thereby, the density of the plasma irradiated to the plastic film can be adjusted, and the degree of surface treatment applied to the plastic film can be adjusted. In addition, the plasma generation surface of the plasma generation unit 13 facing the processing roll 51 is preferably curved according to the shape of the peripheral surface of the processing roll 51 that supports the plastic film 39. Thereby, the distance between the plastic film 39 moving on the peripheral surface of the processing roll 51 and the plasma generation surface can be made constant at all times. Therefore, the plasma irradiated on the plastic film 39 during the movement of the processing roll 51 becomes uniform. As a result, the plasma dose can be easily adjusted.

  The processing roll 51 includes temperature adjusting means for controlling the temperature of the peripheral surface and thereby adjusting the temperature of the plastic film 39 supported on the peripheral surface (not shown). The temperature adjusting means includes, for example, a pipe through which the refrigerant circulates and a refrigerant control unit that controls the amount and / or temperature of the refrigerant that circulates the pipe. The temperature of the plastic film is preferably adjusted to about-(minus) 20 degrees to 40 degrees. In general, a plastic film is easily damaged by being deformed and denatured by heat. However, by providing a temperature adjusting means, it is possible to prevent the plastic film from being damaged by the heat of plasma irradiation.

  In addition, although the example which has two plasma generation parts 13 is shown in FIG. 8, the number of the plasma generation parts 13 is not restricted to this, Three or more may be sufficient. Thereby, since plasma can be generated in a wide range, sufficient surface treatment can be performed even if there is little plasma generated in each plasma generator 13. Therefore, rapid heating due to high-density plasma can be prevented, and the risk of damaging the plastic film by heat can be reduced.

  Hereinafter, although an example is shown and the effect of microwave plasma relevant to the present invention is explained concretely, the present invention is not limited to an example. The conditions of the plasma apparatus used in the examples will be described. The container is a metal, cylindrical container having a diameter of 30 cm and a height of 40 cm. The length of the rectangular waveguide provided in the container is 50 cm. The dielectric plate provided in the plasma generating part has a disc shape with a diameter of 30 cm.

Example 1
In Example 1, the gas was argon and the pressure was 13 Pa. The frequency of the supplied microwave is 2.45 GHz, and the power is 1 kW. The plastic film is a PET (polyethylene terephthalate) film (A4100, manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm and disposed at a position 50 mm from the plasma generation surface. The plasma irradiation time was 5 seconds. After the surface treatment under such conditions, the amount of various elements on the surface of the plastic film subjected to the surface treatment was measured by ESCA (Electron Spectroscopy for Chemical Analysis). The measurement results in Example 1 are shown in FIGS. 9 and 10 show the measurement results of silicon (Si) and fluorine (F), respectively. In FIG. 9, the position 61 shows the spectrum of SiO ₂ , the position 63 shows the spectrum of metal Si, and the dotted elliptical area 65 shows the spectrum of silicon. In FIG. 10, a dotted elliptical region 67 indicates a fluorine spectrum. Compared with untreated PET film, fluorine which is surface contamination is removed.

(Comparative Example 1)
In Comparative Example 1, plasma was generated by applying a DC voltage to a boron-doped silicon plate electrode applied with a magnetic field and installed in the apparatus. The gas was argon and the pressure was 0.6 Pa. DC power was supplied at 4.6 w / cm ² . The plastic film is a PET film (A4100, manufactured by Toyobo Co., Ltd.), which is disposed at a position of 95 mm from the electrode and has a thickness of 100 μm. Plasma irradiation was performed for 2.5 seconds. Although fluorine element is not detected as compared with the untreated film surface, it can be seen that silicon element as an electrode material is present as an impurity on the film surface.

(Example 2)
In Example 2, the gas was 100% argon and a mixed gas (90% argon, 10% oxygen), and the total pressure was 13 Pa. The frequency of the supplied microwave is 2.45 GHz, and the power is 0.5 kW. The plastic film is a PET (polyethylene terephthalate) film (A4100, manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm and disposed at a position 100 mm from the plasma generation surface. The plasma irradiation time was carried out at five levels of 0, 2, 5, 10, and 30 seconds. Under such conditions, after performing surface treatment for each gas by changing the plasma irradiation time, the contact angle with water was measured. FIG. 11 shows the measurement results. Example 2A shows the measurement results with 100% argon, and Example 2B shows the measurement results with the mixed gas. Just exposing to plasma for a few seconds decreased the contact angle, and the effect of surface treatment appeared. When a small amount of oxygen is added, the treatment effect is dramatically improved.

(Example 3)
In Example 3, compared with Example 2, the material of the plastic film was changed from a PET film to a polyimide film. Since the polyimide film has better heat resistance than the PET film, the microwave output is also increased. Specifically, in Example 3, the gas was 100% argon and a mixed gas (90% argon, 10% oxygen), and the total pressure was 13 Pa. The frequency of the supplied microwave is 2.45 GHz, and the power is 1 kW. The plastic film is a polyimide film (Kapton (registered trademark) manufactured by Toray DuPont Co., Ltd.) having a thickness of 50 μm and disposed at a position 50 mm from the plasma generation surface. The plasma irradiation time was carried out at five levels of 0, 2, 5, 10, and 30 seconds. Under such conditions, after the surface treatment was performed for each gas by changing the plasma irradiation time, the contact angle of water was measured. FIG. 12 shows the measurement results, Example 3A shows the measurement results with 100% argon, and Example 3B shows the measurement results with the mixed gas. Similar to the plasma treatment of PET film, the treatment effect appeared in a short time, and the effect was confirmed by adding oxygen.

Example 4
In Example 4, the gas was 100% argon and a mixed gas (90% argon, 10% oxygen), and the total pressure was 65 Pa. The frequency of the supplied microwave is 2.45 GHz, and the power is 1 kW. The plastic film is a polyimide film (Kapton (registered trademark) manufactured by Toray DuPont Co., Ltd.) having a thickness of 50 μm and disposed at a position 50 mm from the plasma generation surface. The plasma irradiation time is 5 seconds.

  After surface treatment under such conditions, carbon (C) and oxygen (0) on the surface of the surface-treated plastic film were measured by ESCA. 13 and 14 show the measurement results of carbon (C) and oxygen (O), respectively. In FIG. 13, position 69 is C═O, position 71 is C—OH, position 73 is C—O—C or C—N, and position 75 is C—C bond. In FIG. 14, a position 79 indicates C—O—C or C—OH, and a position 81 indicates C═O. Example 4A shows the measurement results with 100% argon, Example 4B shows the measurement results with the mixed gas, and Comparative Example 2 shows the measurement results with the untreated polyimide film. From these data, it was found that a C—OH bond was formed on the surface by the plasma treatment, and the chemical surface treatment proceeded.

  Moreover, after surface-treating on the said conditions, the surface roughness of the plastic film which surface-treated was measured. FIG. 15 shows the results of measuring the surface roughness of the treated surface of the polyimide film. The surface roughness is measured by using an AFM (Atomic Force Microscope) to measure the height of the surface irregularities, and the RMS (root mean square) is used as an index. Example 4A shows the measurement results with 100% argon, Example 4B shows the measurement results with the mixed gas, and Comparative Example 2 shows the measurement results with the untreated polyimide film. From this data, it can be seen that the plasma treatment increases the surface roughness and the physical treatment also proceeds. It has also been found that the treatment effect is greater when oxygen is added, both chemically and physically.

(Example 5)
In Example 5, the gas was argon and the pressure was 65 Pa. The frequency of the supplied microwave is 2.45 GHz, and the power is 1 kW. The plastic film is a polyimide film (PMDA-ODA) disposed at a position 100 mm from the plasma generation surface. The plasma irradiation time is 5 seconds. Next, a copper thin film was formed on the surface-treated polyimide film by a DC magnetron sputtering method. In the thin film formation process, the target was oxygen free copper, the distance between the target and the polyimide film was 100 mm, and the supplied power was 50 W in an argon atmosphere of 0.65 Pa. The formed thin film has a thickness of 100 nm. Subsequently, the polyimide film on which the thin film was formed was taken out from the apparatus, and a copper layer was further laminated by 20 μm by electroplating. Electroplating is a general method using copper sulfate as the plating solution and a copper plate for the anode. Based on JIS C6471, the copper layer laminated | stacked by sputtering method and electroplating was peeled off from the interface of a polyimide film and the copper layer by sputtering, and the adhesive force was measured by the 90 degree peeling angle. The results are shown in FIG.

(Example 6)
Example 6 is the same as Example 5 except that the gas is a mixed gas (argon 90%, oxygen 10%).
(Comparative Example 3)
In Comparative Example 3, plate electrode plasma was used instead of microwave plasma as a plasma generation source for plasma surface treatment. Copper was used for the electrode, the frequency of the supplied microwave was 13.56 MHz, the power was 200 W, the film was processed in argon plasma for 5 seconds, and a copper thin film was formed in the same manner as in Example 5 to form an adhesive force. Was measured. The results are shown in FIG.
(Comparative Example 4)
A surface treatment was not performed, a copper thin film was formed by the same method as in Example 5, and the adhesion was measured. The results are shown in FIG. Compared with each of Comparative Examples 3 and 4, Examples 5 and 6 in which surface treatment was performed using microwave plasma had an increased adhesion.

  INDUSTRIAL APPLICABILITY The present invention can be used for a plasma generator, and more specifically, an apparatus for generating plasma for surface treatment of a substrate as a pretreatment for forming an inorganic thin film such as FPC or ITO using a plastic film or the like as a substrate. Can be used for etc.

The figure which shows the outline | summary of a structure of the plasma processing apparatus which concerns on one embodiment of this invention. The top view of the 2nd waveguide which has the slot antenna which concerns on Embodiment 1 of this invention. The side sectional view of the 2nd waveguide which has the slot antenna concerning Embodiment 1 of the present invention. The figure which shows arrangement | positioning of the 2nd waveguide which has a slot antenna which concerns on Embodiment 1 of this invention. The figure which shows the specific example of arrangement | positioning of the waveguide part which has a slot antenna. The notch figure which shows the structure of the 2nd waveguide which has the slot antenna which concerns on Embodiment 2 of this invention. The figure which shows the outline | summary of a structure of the thin film forming apparatus provided with the plasma processing unit which concerns on Embodiment 3 of this invention. The figure which shows the outline | summary of a structure of the thin film forming apparatus provided with the plasma processing unit which concerns on Embodiment 4 of this invention. The figure which shows the silicon (Si) spectrum which measured the process surface of the plastic film by ESCA. The figure which shows the fluorine (F) spectrum which measured the process surface of the plastic film by ESCA. The figure which shows the relationship between the time which surface-treats a PET film, and the contact angle of water in a process surface. The figure which shows the relationship between the time which surface-treats a polyimide film, and the contact angle of the water in a process surface. The figure which shows the carbon (C) spectrum which measured the process surface of the polyimide film by ESCA. The figure which shows the oxygen (O) spectrum which measured the process surface of the polyimide film by ESCA. The figure which shows the result of having measured the surface roughness of the process surface of a polyimide film. The figure which shows the peeling strength of the copper layer formed in the process surface of a polyimide film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus, 2 Plasma apparatus, 3 Container, 4A 1st waveguide, 4B Tapered connection tube, 4C connection part, 5 2nd waveguide, 7 units | sets, 9 Plastic film, 10 Slot antenna, 11 Dielectric Plate, 12 slots, 13 Plasma generator, 31 Unwinding unit, 33a / 33b Plasma processing unit, 35 Film forming unit, 37 Winding unit, 39 Plastic film, 41 Unwinding roll, 43 Guide roll, 45 Main roll, 47 Sputter target, 49 winding roll, 51 processing roll, 53 permanent magnet

Claims (13)

A plasma device for generating microwave plasma in a container,
A wall portion that forms a rectangular cross-sectional shape, a waveguide portion that is attached to the container and transmits microwaves having a free-space wavelength λ,
A slot antenna composed of a plurality of rectangular slots formed in the longitudinal direction of the waveguide section at intervals of ½ of the guide wavelength λg on the wall section;
A dielectric plate that is provided in contact with the outer surface of the wall portion having the slot antenna and covers the slot antenna;
The plurality of slots forming the slot antenna are
a) Alternatingly arranged across the central axis in the longitudinal direction of the wall portion having the slot antenna,
b) the distance from the central axis is constant;
c) When the number of the plurality of slots is n (excluding n = 1) and n × λg / 2 is divided by λ / 2 and m is obtained, m−1 <n <m is satisfied. ,
d) Satisfying the relationship of Equations 1 and 2, and the impedance of the waveguide portion viewed from the microwave power supply side is substantially equal to the characteristic impedance of the waveguide portion viewed from the opposite power supply side,
A plasma apparatus characterized by satisfying the conditions a) to d).

g: Equivalent conductance of one slot normalized by the characteristic impedance of the waveguide section under idealized conditions
a: Height of the waveguide section
b: width of the waveguide section
x1: Distance from the central axis in the longitudinal direction of the wall to the central axis in the longitudinal direction of the slot A waveguide for transmitting microwaves from the microwave power source to the waveguide section;
A tapered connecting pipe for smoothly connecting the waveguide and the waveguide section;
The plasma apparatus according to claim 1, further comprising: A plasma processing apparatus for processing the surface of an object by irradiating the object to be processed with plasma in a container,
A plasma generator for generating microwave plasma in the container;
A support part for supporting the object in a state facing the plasma generation part,
A waveguide section that has a wall section that forms a rectangular cross-sectional shape, is mounted on the container, and transmits microwaves having a free-space wavelength λ;
A slot antenna composed of a plurality of rectangular slots formed in the longitudinal direction of the waveguide section at intervals of ½ of the guide wavelength λg on the wall section;
A dielectric plate that is provided in contact with the outer surface of the wall portion having the slot antenna and covers the slot antenna;
The plurality of slots forming the slot antenna are
a) Alternatingly arranged across the central axis in the longitudinal direction of the wall portion having the slot antenna,
b) the distance from the central axis is constant;
c) When the number of the plurality of slots is n (excluding n = 1) and n × λg / 2 is divided by λ / 2 and m is obtained, m−1 <n <m is satisfied. ,
d) Satisfying the relationship of Equations 1 and 2, and the impedance of the waveguide portion viewed from the microwave power supply side is substantially equal to the characteristic impedance of the waveguide portion viewed from the opposite power supply side,
The plasma processing apparatus characterized by satisfying the conditions a) to d).

g: Equivalent conductance of one slot normalized by the characteristic impedance of the waveguide section under idealized conditions
a: Height of the waveguide section
b: width of the waveguide section
x1: Distance from the central axis in the longitudinal direction of the wall to the central axis in the longitudinal direction of the slot   The plasma processing apparatus according to claim 3, further comprising a plurality of permanent magnets on the dielectric plate or in the vicinity thereof on the side facing the object. The object is a long plastic film,
The plasma processing apparatus according to claim 3, wherein the support part continuously moves the plastic film.   The plasma processing apparatus according to any one of claims 3 to 5, wherein the support part has a temperature adjusting means for adjusting the temperature of the plastic film supported by the support part.   The plasma processing apparatus according to claim 3, further comprising a distance adjustment mechanism that adjusts a distance between the plasma generation unit and the object.   8. The plasma generating unit according to claim 3, wherein the plasma generating unit is curved according to a shape of a surface of the support unit that supports the plastic film so that a distance from the plastic film is constant. 2. The plasma processing apparatus according to item 1.   The plasma processing apparatus according to claim 3, wherein a plurality of the plasma generation units are provided along a moving direction of the plastic film.   The plasma processing apparatus according to any one of claims 3 to 9, wherein the support portion is a roll that is rotatable and sequentially moves the plastic film by rotating. A waveguide for transmitting microwaves from the microwave power source to the waveguide section;
A tapered connecting pipe for smoothly connecting the waveguide and the waveguide section;
The plasma processing apparatus according to claim 3, further comprising: A waveguide section that has a wall section that forms a rectangular cross-sectional shape, is mounted on a hollow container, and transmits microwaves having a free-space wavelength λ;
A slot antenna composed of a plurality of rectangular slots formed in the longitudinal direction of the waveguide section at intervals of ½ of the guide wavelength λg on the wall section;
A dielectric plate that is provided in contact with the outer surface of the wall portion having the slot antenna and covers the slot antenna;
The plurality of slots forming the slot antenna are
a) Alternatingly arranged across the central axis in the longitudinal direction of the wall portion having the slot antenna,
b) the distance from the central axis is constant;
c) When the number of the plurality of slots is n (excluding n = 1) and n × λg / 2 is divided by λ / 2 and m is obtained, m−1 <n <m is satisfied. ,
d) Satisfying the relationship of Equations 1 and 2, and the impedance of the waveguide portion viewed from the microwave power supply side is substantially equal to the characteristic impedance of the waveguide portion viewed from the opposite power supply side,
A surface treatment method for performing a surface treatment of an object using a plasma generating part that satisfies the conditions a) to d),
Radiating microwaves from a slot antenna formed on the wall of the waveguide section;
Generating a plasma on the surface of the dielectric plate provided in the plasma generator by the microwave;
Irradiating the object with the generated plasma. A plasma processing method comprising:

g: Equivalent conductance of one slot normalized by the characteristic impedance of the waveguide section under idealized conditions
a: Height of the waveguide section
b: width of the waveguide section
x1: Distance from the central axis in the longitudinal direction of the wall to the central axis in the longitudinal direction of the slot A waveguide for transmitting microwaves from the microwave power source to the waveguide section;
A tapered connecting pipe for smoothly connecting the waveguide and the waveguide section;
The plasma processing method according to claim 12, further comprising:

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