JP2009302566A - Plasma surface processor with balanced-unbalanced transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that in a plasma surface processor, particularly in a high-speed film forming plasma CVD apparatus, supply of high-frequency electricity to electrodes causes waste of large amount of the electricity in parts other than the electrodes and in addition an abnormal rise of temperatures of electricity supplying circuit components in a vacuum container, while resulting in reduction of operation rate of the plasma CVD apparatus due to degradation and burnout of the electricity supplying circuit components and quality deterioration of products. <P>SOLUTION: An balanced-unbalanced transformer and a temperature controller are placed in a vacuum container so that the temperature of the balanced-unbalanced transformer is controlled at a value between 50°C to 150°C, wherein a plurality of coaxial cables are used as windings of a toroidal core in the transformer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface treatment apparatus and a surface treatment method for performing a predetermined treatment on a surface of a substrate using plasma. The present invention particularly relates to a thin film silicon solar cell and a plasma CVD apparatus and method for manufacturing a TFT (thin film transistor), which require high quality and high speed film formation.

  Manufacturing various electronic devices by applying various treatments to the surface of the substrate using plasma is the process of LSI (Large Scale Integrated Circuit), LCD (Liquid Crystal Display) TFT (Thin Film Transistor), amorphous silicon solar cell and microcrystalline silicon. It has already been put into practical use in fields such as solar cells.

In recent years, as one of the important needs regarding a plasma surface treatment apparatus and a plasma surface treatment method, application to the production of thin film silicon solar cells is increasing.
In the field of thin-film silicon solar cells, integrated tandem thin-film solar cells combining amorphous silicon and microcrystalline silicon are attracting attention, and their practical application aiming at full-scale popularization is rapidly progressing.
An integrated tandem thin film silicon solar cell has a transparent electrode layer, an amorphous silicon photoelectric conversion unit layer, a function of reflecting short wavelength light and transmitting long wavelength light to a light transmissive substrate (for example, glass). Is formed by sequentially laminating an intermediate layer, a crystalline silicon photoelectric conversion unit layer, and a back electrode layer.
The amorphous silicon photoelectric conversion unit layer is composed of a p-type semiconductor layer, an i-type semiconductor layer, an n-type semiconductor layer, and the like, and the thickness of the entire pin layer is about 0.3 μm.
The crystalline silicon photoelectric conversion unit layer is composed of a p-type microcrystalline semiconductor layer, an i-type microcrystalline semiconductor layer, an n-type microcrystalline semiconductor layer, etc., and the thickness of the entire pin layer is about 2.5 to 5 μm. . Note that the i-type microcrystalline semiconductor layer has a thickness of about 2 to 4 μm.
The production line for manufacturing solar cells combining amorphous silicon and crystalline silicon called so-called integrated tandem thin-film solar cells is expected to be able to manufacture high-efficiency modules with a photoelectric conversion efficiency of 10 to 13%. ing.

However, the integrated tandem-type thin film solar cell has the merit that the photoelectric conversion efficiency can be easily improved, but the i-type microcrystalline semiconductor of the crystalline silicon photoelectric conversion unit layer that requires a thickness of about 2 to 4 μm. A great deal of time is required to produce the layer. Therefore, it is necessary to install a plurality of i-type microcrystalline semiconductor layer manufacturing apparatuses, which has a demerit that production cost increases.
In recent years, in order to eliminate this disadvantage, development of a technique for improving the deposition rate of an i-type microcrystalline semiconductor layer and development of a plasma CVD apparatus capable of manufacturing a large area with high quality and good uniformity have been carried out. It has been broken.
Recently, as a technique for improving the film forming speed of the i-type microcrystalline semiconductor layer, a method using a VHF (very high frequency band: 30 MHz to 300 MHz) plasma CVD apparatus is diluted with a large amount of hydrogen as a film forming condition. This can be realized by using silane gas (SiH4) and supplying high power at high pressure.
However, when plasma generation is performed under high-speed film conditions, the output power of the high-frequency power source, that is, the high-frequency power of the HF region frequency (3 MHz to 30 MHz) or VHF region (30 MHz to 300 MHz) When supplying the electrodes, power is consumed at a place or member other than the pair of electrodes. Consumption of power at a place or member other than the pair of electrodes suffers a great power loss, and at the same time, unnecessary plasma is generated at an unnecessary place, which is a problem in terms of plasma control. Since the power consumption other than the pair of electrodes is great, it is a wasteful use of the supplied power, which is one of the causes of an increase in product cost.
Furthermore, the consumption of power other than the pair of electrodes causes an abnormal increase in temperature of the power supply circuit components in the vacuum vessel, causing deterioration and burnout of the power supply circuit components.
As a result, the operating rate of the plasma CVD apparatus is lowered and the quality of manufactured products is lowered.
Furthermore, in the plasma CVD apparatus for manufacturing thin film silicon solar cells and TFTs (thin film transistors) that are generally used at production sites, the film forming chambers are arranged in either an inline type, a multi-chamber type, or a parallel type. However, the arrangement of the power supply line for generating plasma is often limited due to the balance with the substrate transfer device and the like. As a result, it is necessary to change the power propagation direction to an acute angle in the coaxial cable wiring, which is one of the components of the power supply line. In this case, an L-shaped connector for a coaxial cable is used. In this case, there is the following problem.
That is, the structure of the L-shaped connector used in the atmosphere includes, for example, a linear coaxial cable 100 composed of a core wire 105, an outer conductor 106, and a dielectric 107, a core wire 108, and an outer conductor 109, as shown in FIG. It has a structure in which a linear coaxial cable 101 made of a dielectric 110 is connected by a portion 111 bent in an L shape. The vicinity of the core wire of the L-shaped bent portion 111 is a gap. Therefore, the characteristic impedance at the bent portion is significantly different from that of the straight portion of the coaxial cable. In addition, since the speed of the power wave propagating inside the coaxial cable is determined by the characteristics (dielectric constant and permeability) of the dielectric used in the coaxial cable, the power is bent in an L shape in the power transmission path. In order to bend based on the same principle as the prism placed in the light propagation path, the distribution of the characteristics (dielectric constant and permeability) of the dielectric of the L-shaped part, for example, to have a prismatic distribution Therefore, it is necessary to make sure that there is no unreasonable power propagation. However, since it is difficult to give the dielectric of a coaxial cable, for example, a prismatic distribution, it has not been realized yet.
Further, in the case of the structure in which the vicinity of the core wire of the bent portion of the L-shaped connector used in the atmosphere is filled with a dielectric, for example, in the case of the L-shaped connector for vacuum as shown in FIG. 10, the characteristic impedance at the bent portion Is significantly different from the straight section of the coaxial cable. That is, the characteristic impedance of the linear coaxial cable portion 100 comprising the core wire 105, the outer conductor 106 and the dielectric 107 shown in FIG. 10 and the linear coaxial cable portion 101 comprising the core wire 108, the outer conductor 109 and the dielectric 110 are shown. The characteristic impedance at the bent portion 111 is significantly different. Even in the form of power propagation, the speed of the power wave propagating through the coaxial cable is determined by the characteristics (dielectric constant and permeability) of the dielectric used in the coaxial cable. In the case of bending, the distribution of the characteristics (dielectric constant and permeability) of the L-shaped dielectric so that it bends based on the same principle as that of the prism placed in the light propagation path, for example, prismatic distribution It is necessary to make it impossible to propagate power by providing That is, the radio wave 112 propagating outside the core wire in the L-shaped portion shown in FIG. 10 propagates at a high speed, and the radio wave 113 propagating inside thereof is impossible unless propagated at a low speed. However, even in the coaxial cable for vacuum, since it is difficult to give the dielectric of the coaxial cable, for example, a prismatic distribution, it has not been realized yet.
That is, when power is transmitted using a coaxial cable having an acute bend as shown in FIGS. 9 and 10, strong power reflection occurs due to a discontinuous change in impedance at the bend, and the inner side of the core wire. A large amount of Joule heat is generated due to an increase in electrical resistance due to the difference in the power transmission path between the outside and the outside.
Therefore, problems in the field of plasma surface treatment apparatuses such as the above plasma CVD apparatus include problems of deterioration and burnout of power supply circuit components in the vacuum vessel due to power consumption in places and members other than between the pair of electrodes, There is a problem of power loss and burning that occur in the L-shaped connector portion of the coaxial cable installed in the vacuum vessel.

Non-Patent Document 1 discloses a technique relating to high-quality and high-speed film formation of a crystalline i-layer film for an integrated tandem thin-film solar cell by VHF plasma CVD using parallel plate electrodes.
That is, as experimental conditions, parallel plate electrode size: diameter 10 cm, source gas: high hydrogen diluted SiH4, pressure: 2-4 Torr (133-532 Pa), substrate temperature: 250 ° C., power supply frequency: 60 MHz, input power: film formation It is shown that high-quality microcrystalline Si can be obtained by setting the speed to 2.54 W / cm 2 at a speed of 1.7 nm / s and 3.4 W / cm 2 at 2.5 nm / s.
It has also been shown that high-quality microcrystalline Si can be obtained by using VHF plasma CVD with a frequency of 60 MHz even under high-speed film forming conditions of 1.7 to 2.5 nm / s.
The input power is 2.54 W / cm 2 when the film forming speed is 1.7 nm / s, and 3.4 W / cm 2 when the film forming speed is 2.5 nm / s, which means that very large power is required. For example, in the case where the substrate area is 110 cm × 140 cm (15400 cm 2), if proportional calculation is simply performed, 39.1 kW is necessary when the film forming speed is 1.7 nm / s, and 52.4 kW is necessary when the film forming speed is 2.5 nm / s. It means that.

On the other hand, Non-Patent Document 2 shows the results of research on power consumption in plasma generation using parallel plate electrodes.
That is, an N2 plasma generation experiment was conducted by applying 13.56 MHz power to a parallel plate electrode (size: diameter 15 cm, electrode interval: 5 cm) installed in a vacuum vessel having a diameter of 30 cm through an impedance matching device. It is shown that the amount of power consumed is measured.
As a result of the measurement, about 52% of the power output (300W) is consumed between the parallel plate electrodes, and the remaining 48% is consumed elsewhere (impedance matching device 12%, transmission circuit 24%, electrode and vacuum vessel It is shown that the ineffective plasma generation between the inner walls is 12%).
The above means that in an RF plasma CVD apparatus using parallel plate electrodes, about 52% of the power supplied from the power source is consumed between the target electrodes.

Patent Document 1 discloses a semi-rigid coaxial cable having a bent portion whose power propagation direction is bent at an acute angle in a power supply line inside a vacuum vessel.
Further, in Patent Document 1, a cylinder, a discharge electrode stored in the cylinder, a substrate installed opposite to the electrode, and the electrode opposite to the substrate are opposed to the electrode. An electrode connecting connector for electrically connecting the electrode and a feeding cable that supplies power to the cylinder from a high-frequency power source installed outside the cylinder, A vacuum plasma processing apparatus is shown in which a connection point between a power feeding cable and the electrode connector is installed on the opposite side of the electrode with respect to the deposition preventing plate.

Patent Document 2 shows a power supply circuit having a heat medium supply pipe through which a heat medium for cooling flows in an electric power supply line inside a vacuum vessel and having an L-shaped bent portion.
Further, in Patent Document 2, the impedance on the output side can be matched, and a first matching unit that transmits the supplied first power and one end connected to the first matching unit to transmit the first power. A first feeding transmission line that mediates, a discharge electrode that is connected to the other end of the first feeding transmission line and that receives the first power, and a counter electrode facing the discharge electrode; A thin film manufacturing apparatus having a characteristic impedance of a transmission line of 20Ω to 300Ω is shown.
In the thin film manufacturing apparatus, the first power transmission line is provided in a tubular shape inside the first outer conductor, apart from the hard tubular first outer conductor and the inner peripheral surface of the first outer conductor. And a first inner conductor provided inside the first insulator and spaced from the inner peripheral surface of the first insulator, the first outer conductor and the first insulator. And the distance between the first insulator and the first outer conductor are 0.1 mm or more and 1 mm or less, respectively.

Patent Document 3 discloses an apparatus and a method related to a technique for installing a balance-unbalance conversion device between an impedance matching unit and a feeding point on an electrode in a power supply circuit.
That is, the technique described in Patent Document 3 is an impedance matching between a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for plasma generation, and a high-frequency power source. And a substrate holding means for arranging a substrate to be plasma-processed, and used for a plasma surface processing apparatus for processing the surface of the substrate using the generated plasma. A balanced transmission circuit in which two outer conductors of coaxial cables having substantially the same length are short-circuited at both ends, and each core wire at one end of the two coaxial cables is input. A balanced transmission circuit having a configuration in which each core wire at the other end is used as an output unit.
In addition, the technique described in Patent Document 3 includes impedance matching between a vacuum vessel provided with an exhaust system, a discharge gas supply system that supplies a discharge gas into the vacuum vessel, an electrode for plasma generation, and a high-frequency power source. And a substrate holding means for arranging a substrate to be plasma-processed, and used for a plasma surface processing apparatus for processing the surface of the substrate using the generated plasma. A balanced transmission circuit, in which two outer conductors of coaxial cables having substantially the same length are short-circuited by other conductors at both ends, and one end of each of the two coaxial cables The balanced transmission circuit has a configuration in which the core wire is used as an input unit, and each core wire at the other end is used as an output unit.
Further, the technique described in Patent Document 3 includes a vacuum vessel provided with an exhaust system, a discharge gas supply system that supplies a discharge gas into the vacuum vessel, and first and second electrodes that generate plasma. A pair of electrodes, a power supply point for the pair of electrodes, a power supply system including a high-frequency power source, an impedance matching device, and a balance-unbalance converter, a substrate holding means for arranging a substrate to be plasma-treated, An apparatus configuration of a power supply circuit that supplies a power from the power supply system to the pair of electrodes in a plasma surface treatment apparatus that includes a balanced transmission circuit having a configuration and processes the surface of a substrate using generated plasma. The high-frequency power supply, the impedance matching device, the balance-unbalance conversion device, the balanced transmission circuit, and the power supply point are arranged in the order from the upstream side to the downstream side of the power flow. A plasma surface treatment apparatus.
Patent Document 3 discloses that a conventional plasma CVD apparatus using a parallel plate electrode and a plasma CVD apparatus using a ladder-type electrode generate a leakage current in a power feeding portion to the electrode used in the apparatus. It has been pointed out that abnormal discharge or arcing occurs, and that plasma is generated at a place other than the pair of electrodes, making uniform film formation difficult.
That is, in the conventional plasma CVD apparatus, the connection portion between the coaxial cable for supplying power and the electrode has a shape in which lines having different structures are connected to each other, and a leakage current is generated at the connection portion. The coaxial cable is a transmission system in which the inner conductor (core wire) and the inner surface of the outer conductor are the forward path and the return path, respectively, and the pair of electrodes has a structure corresponding to two parallel lines.

Patent Document 4 discloses an apparatus and a method related to a technique for installing a balance-unbalance conversion device between an impedance matching unit and a feeding point on an electrode in a power supply circuit.
In Patent Document 4, in a surface treatment apparatus that treats the surface of a substrate placed in a vacuum vessel using plasma, a pair of electrodes opposed to each other in the vacuum vessel and power to the pair of electrodes are respectively supplied. A coaxial cable to be supplied, a power supply point that is installed on each of the pair of electrodes and connected to a core wire of the coaxial cable, and power is supplied from the coaxial cable, and power is supplied to one electrode of the pair of electrodes. The other conductor that connects the outer conductor of the coaxial cable to be supplied and the outer conductor of the coaxial cable that supplies power to the other electrode in the vicinity of the respective feeding points, and is supplied to the pair of electrodes. Further, there is described a surface treatment apparatus characterized in that the phase difference of the voltage of the electric power is 180 °.
Further, Patent Document 4 discloses a pair of electrodes opposed to each other in a vacuum vessel, a coaxial cable that supplies power to each of the pair of electrodes, and a core wire of the coaxial cable that is installed on each of the pair of electrodes. Are connected, a feeding point to which power is supplied from the coaxial cable, an outer conductor of the coaxial cable that supplies power to one electrode of the pair of electrodes, and the coaxial cable that supplies power to the other electrode Using a surface treatment apparatus provided with other conductors that connect the outer conductors in the vicinity of the respective feeding points, a substrate is disposed between the pair of electrodes, and the surface of the substrate is removed using plasma. In the surface treatment method to be processed, the method includes the steps of exhausting the inside of the vacuum vessel, supplying a discharge gas into the vacuum vessel, and supplying power to both the pair of electrodes, Serial describes a surface treatment wherein the phase difference between the voltage of the pair of the power supplied to the electrode is 180 °.

JP 2006-206935 A (FIGS. 3 and 6) JP-A-2006-278777 (FIG. 5) Japanese Patent No. 3590955 (Figs. 1-8 and 15-17) Japanese Patent No. 3810748 (Fig. 1-5)

M.M. Kondo, M .; Fukawa, L .; Guo, A.A. Matsuda: High rate growth of microcrystalline silicon at low temperatures, Journal of Non-Crystalline Solids 266-269 (2000), 84-89. J. et al. A. Baggerman, R.A. J. et al. Visser, and E.M. J. et al. H. Collart: Power distribution measurements in a low-pressure N2 radio-frequency discharge, J. Biol. Appl. Phys. Vol. 76, no. 2, 15 July 1994, 738-746.

When the high frequency power of the above-mentioned two problems, that is, the frequency of the HF region (3 MHz to 30 MHz) or the frequency of the VHF region (30 MHz to 300 MHz) is supplied to the pair of electrodes for plasma generation, other than the pair of electrodes In addition to the wasteful power consumption consumed by places and members, power consumption other than the pair of electrodes causes an abnormal increase in temperature of power supply circuit components in the vacuum vessel, and the power Since it causes deterioration and burnout of supply circuit components, it causes the first problem that the operating rate of the plasma CVD apparatus is lowered and the quality of the manufactured product is lowered, and the frequency of the HF region (3 MHz to 30 MHz). Alternatively, when supplying high frequency power having a frequency in the VHF region (30 MHz to 300 MHz) to a pair of electrodes for plasma generation, a coaxial cable is arranged. When the L-shaped connector is used above, the second problem of reflection of electric power generated in the L-shaped connector portion and power consumption (power loss) due to Joule heat generation and occurrence of burning out of the L-shaped connector portion. There is. This second problem is regarded as a problem in particular in the field of thin-film silicon solar cells as one of the factors that cause a reduction in the operating rate of the apparatus.
That is, when using a plasma CVD apparatus at the production site, it is difficult to reduce the product manufacturing cost due to the waste of power that cannot be controlled in operation of the apparatus, and the reactive power that does not contribute to film formation. It is an important issue to solve the problem that the operating rate of the apparatus is inevitably lowered due to burning or deterioration of the power supply circuit due to the occurrence of abnormalities and abnormal temperature rise.
An object of the present invention is to create an idea that can solve the above two problems and to create a means that can realize the idea.
That is, an object of the present invention is to provide a technique capable of suppressing power loss in a power supply circuit used in a plasma surface treatment apparatus.

Means for solving the problem will be described below, but the present inventor has intensively studied where the cause of the problems of the prior art is. As a result, the following matters were found to be the root of the problem. That is, it has been found that it is sufficient to create means for solving the following problems.
(A) Problems related to grounding of the high-frequency power supply, the vacuum vessel, and the electrodes, and more particularly, problems related to leakage current that occurs in power transmission using a coaxial cable. That is, the high-frequency power source 115, the impedance matching unit 117, the vacuum vessel 120, the non-ground electrode 121, the ground electrode 122, the coaxial cables 116 and 118 shown in FIG. 11, and the current introduction terminal including the core wire 119a, the dielectric 119b, and the external conductor 119c. In the plasma surface treatment apparatus having 119 as a constituent member, even if the electrode 121 is insulated from the ground 130 in terms of direct current, there is an influence of grounding in terms of high frequency. The problem is that the output of the high frequency power supply 115 supplied via the impedance matching unit 117 and the coaxial cable is strongly influenced by, for example, the ground lines 127, 128, and 129. That is, since the coaxial cables 116 and 118 that are unbalanced transmission lines are used as the high-frequency power transmission means, at least the impedance matching unit 117, the coaxial cable 118, and the current introduction terminal 119 are affected by the ground. Specifically, the output current of the impedance matching unit 117 flows through the core wire of the coaxial cable 118, the inner side of the outer conductor, the outer side of the outer conductor, and the ground 130. Conceptually, there is a current I flowing through the core wire and the outer conductor of the coaxial cable 118 shown in FIG. 11 and a current Ix flowing through the ground 130. It should be noted that the current I is preferably called a differential current or a balanced transmission system current I (the way in which the amplitudes of the forward and return currents are equal and the phases are 180 ° different). On the other hand, the current Ix shown in FIG. 11 is called leakage current or common-mode current. This leakage current Ix is a cause of generating plasma generated other than between the electrodes 121 and 122, for example, unnecessary plasmas 124, 125, and 126 shown in FIG.
(Ii) When a coaxial cable used in the atmosphere and in a vacuum vessel is installed at an acute angle, for example, bent in an L shape, it propagates through the coaxial cable as shown in FIGS. Since radio waves do not bend smoothly, there is a problem that a large loss of power occurs at the L-shaped bent portion. This problem has a problem that another means must be selected unless an idea is considered in consideration of the essential properties of wave propagation, similar to a prism used in the optical field.
Therefore, it is important to create means for solving the above problems (a) and (ii).

In order to achieve the above object, the present invention provides the following means.
A plasma surface treatment apparatus according to a first aspect of the present invention, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, In a plasma surface treatment apparatus comprising a power supply system comprising an impedance matching unit and a balance-unbalance conversion device and substrate holding means for placing a substrate to be plasma-treated, and processing the surface of the substrate using the generated plasma In addition, a transformer-type balanced / unbalanced converter is disposed as the balanced / unbalanced conversion device.

  A plasma surface treatment apparatus according to a second aspect of the present invention comprises a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, and a high frequency power source Surface processing apparatus for processing the surface of the substrate using the generated plasma, comprising: a power supply system comprising an impedance matching unit and a balance-unbalance conversion device; and a substrate holding means for arranging a substrate to be plasma-processed In the apparatus configuration of the power supply system, two conductors of a high-frequency power source, an impedance matching unit, a transformer-type balanced / unbalanced converter, and an ungrounded line are used as power lines from the upstream side to the downstream side of the power flow. They are arranged in the order of current introduction terminals.

  According to a third aspect of the present invention, there is provided a plasma surface treatment apparatus comprising: a vacuum vessel provided with an exhaust system; a discharge gas supply system for supplying a discharge gas into the vacuum vessel; an electrode for generating plasma; Surface processing apparatus for processing the surface of the substrate using the generated plasma, comprising: a power supply system comprising an impedance matching unit and a balance-unbalance conversion device; and a substrate holding means for arranging a substrate to be plasma-processed The balance-unbalance converter includes a transformer-type balance-unbalance converter in which a coaxial cable is used for the winding.

  According to a fourth aspect of the present invention, there is provided a plasma surface treatment apparatus comprising: a vacuum vessel provided with an exhaust system; a discharge gas supply system for supplying a discharge gas into the vacuum vessel; an electrode for generating plasma; In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, a power supply system comprising an impedance matching unit and a substrate holding means for arranging a substrate to be plasma-processed is provided. A transformer-type balanced / unbalanced converter is disposed at a bent portion of the power transmission path in FIG.

  According to a fifth aspect of the present invention, there is provided a plasma surface treatment apparatus comprising: a vacuum vessel provided with an exhaust system; a discharge gas supply system for supplying a discharge gas into the vacuum vessel; an electrode for generating plasma; Surface processing apparatus for processing the surface of the substrate using the generated plasma, comprising: a power supply system comprising an impedance matching unit and a balance-unbalance conversion device; and a substrate holding means for arranging a substrate to be plasma-processed The transformer-type balanced / unbalanced converter in which a single toroidal core and a plurality of coaxial cables are used for the winding wound around the toroidal core, and these are connected in parallel as the balanced / unbalanced conversion device. It is characterized by being arranged.

  According to a sixth aspect of the present invention, there is provided a plasma surface treatment apparatus comprising: a vacuum vessel provided with an exhaust system; a discharge gas supply system for supplying a discharge gas into the vacuum vessel; an electrode for generating plasma; Surface processing apparatus for processing the surface of the substrate using the generated plasma, comprising: a power supply system comprising an impedance matching unit and a balance-unbalance conversion device; and a substrate holding means for arranging a substrate to be plasma-processed In the present invention, a plurality of transformer-type balanced / unbalanced converters including one toroidal core and one coaxial cable are arranged as the balanced / unbalanced converter, and the plurality of transformer-type balanced / unbalanced converters are arranged in parallel. It is characterized by connecting.

  According to a seventh aspect of the present invention, there is provided a plasma surface treatment apparatus according to any one of the first to fourth plasma surface treatment apparatuses according to the present application, wherein the winding of the component member of the transformer type unbalanced converter is started. It has a structure in which the direction of the part of the line and the direction of the line at the end of the winding are substantially orthogonal to each other.

  According to an eighth aspect of the present invention, there is provided a plasma surface treatment apparatus of the fifth or sixth plasma surface treatment apparatus according to the present application, wherein the core wire of the coaxial cable winding start portion of the component of the transformer type balun And the direction of the core wire at the end of the winding are substantially orthogonal to each other.

  A plasma surface treatment apparatus according to a ninth aspect of the present invention is the plasma surface treatment apparatus according to any one of the first to eighth plasma surface treatment apparatuses according to the present application, wherein the temperature of the transformer type unbalanced converter is 50 ° C to 150 ° C. A temperature control device set to an arbitrary value in the range is arranged.

  A plasma surface treatment apparatus according to a tenth aspect of the present invention is the plasma surface treatment apparatus according to any one of the first to ninth plasma surface treatment apparatuses according to the present application, wherein the transformer-type balun is disposed inside the vacuum vessel. It is characterized by that.

  According to an eleventh aspect of the present invention, there is provided a plasma surface treatment apparatus comprising: a vacuum vessel provided with an exhaust system; a discharge gas supply system for supplying a discharge gas into the vacuum vessel; an electrode for generating plasma; Surface processing apparatus for processing the surface of the substrate using the generated plasma, comprising: a power supply system comprising an impedance matching unit and a balance-unbalance conversion device; and a substrate holding means for arranging a substrate to be plasma-processed The power supply system configuration is arranged in the order of a high-frequency power source, a balanced impedance matching device, a transformer-type balanced-unbalanced converter, and a balanced-type current introduction terminal from the upstream side to the downstream side of the power flow. It is characterized by being.

According to the present invention, the above-mentioned two problems that are the problems to be solved by the present invention, namely, firstly, the high frequency power of the frequency of the HF region (3 MHz to 30 MHz) or the frequency of the VHF region (30 MHz to 300 MHz). When supplying to a pair of electrodes for plasma generation, in addition to the wasteful power consumption consumed in places and members other than the pair of electrodes, power consumption other than the pair of electrodes is Since the temperature of the power supply circuit component in the vacuum vessel is abnormally increased, which causes deterioration and burnout of the power supply circuit component, the operating rate of the plasma CVD apparatus is decreased and the quality of the manufactured product is decreased. And secondly, the high frequency power of the frequency of the HF region (3 MHz to 30 MHz) or the frequency of the VHF region (30 MHz to 300 MHz) When an L-shaped connector is used on the coaxial cable wiring when supplying to a pair of electrodes for generation, power consumption due to reflection of power generated at the L-shaped connector portion and generation of Joule heat (power) Loss) and the problem of burning out of the L-shaped connector portion can all be solved.
That is, when using a plasma CVD apparatus at the production site, it is difficult to reduce the product manufacturing cost due to the waste of power that cannot be controlled in operation of the apparatus, and the reactive power that does not contribute to film formation. It is possible to effectively solve the problem that the operating rate of the apparatus is inevitably lowered due to burning or deterioration of the power supply circuit due to the occurrence of abnormalities and abnormal temperature rise.
That is, in an application field of HF plasma and VHF plasma capable of processing a high quality film at high speed, in addition to being able to suppress wasteful power consumption, manufacturing due to abnormal discharge and burning and failure of the power transmission member It is possible to drastically improve the deterioration of the performance quality of the products to be used and the reduction of the equipment operation rate.
Therefore, the present invention is used for production lines in fields such as the manufacture of integrated tandem-type thin film solar cell modules and the manufacture of various devices applying microcrystalline silicon films, thereby increasing productivity due to improved availability. The effect of reducing the manufacturing cost by improving the yield is remarkably large. Moreover, the effect of improving the product performance is remarkably large by suppressing the ineffective discharge plasma. In addition, it is expected that the manufacturing cost can be reduced by minimizing the use of electric power.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In each figure, the same code | symbol is attached | subjected to the same member and the overlapping description is abbreviate | omitted.
In the following description, as an example of a plasma surface treatment apparatus and a plasma surface treatment method, a plasma CVD apparatus and method for producing an amorphous silicon semiconductor layer for solar cells are described. It is not limited to examples.

Example 1
A plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer-type balance-unbalance conversion apparatus according to the first embodiment of the present invention will be described with reference to FIGS. explain.

  FIG. 1 is a schematic view showing an entire plasma surface processing apparatus (plasma CVD apparatus) provided with a transformer-type balance-unbalance conversion apparatus according to the first embodiment of the present invention, and FIG. 2 is a first embodiment of the present invention. FIG. 3 is a schematic diagram showing the entire first transformer-type balanced / unbalanced conversion apparatus according to FIG. 3, and FIG. 3 shows a first balanced / unbalanced converter as a component of the first transformer-type balanced / unbalanced conversion apparatus shown in FIG. FIG. 4 is an explanatory diagram relating to the basic electric circuit of the first transformer type balanced / unbalanced conversion device shown in FIG. 2, and FIG. 5 is an explanatory diagram relating to the electric circuit of the first transformer type balanced / unbalanced converting device. FIG.

First, the configuration of a plasma surface treatment apparatus (plasma CVD apparatus) provided with a transformer-type balance-unbalance conversion apparatus according to the first embodiment of the present invention will be described.
1 to 5, reference numeral 1 denotes a vacuum container. The vacuum vessel 1 includes a discharge gas mixing box 6 to be described later, a pair of electrodes 2 and 3 for plasmaizing a discharge gas to be described later, that is, a non-ground electrode 2, a ground electrode 3 having a substrate heater (not shown), A first transformer-type balance-unbalance conversion device 4 to be described later is disposed.
The non-grounded electrode 2 is installed in the vacuum vessel 1 through insulating support members 5a and 5b and a discharge gas mixing box 6. The ground electrode 3 incorporates a substrate heater for adjusting the temperature of the substrate, which will be described later, and the temperature of the substrate can be set to an arbitrary value within a range of 100 ° C to 350 ° C.
The discharge gas mixing box 6 is used in combination with the rectifying plate 7, the gas supply pipe 8 and the non-grounded electrode 2, and discharges the discharge gas uniformly between the pair of electrodes 2 and 3 from the gas discharge holes 9. In addition, the diameter of the gas ejection hole 9 is about 0.2-1.5 mm, for example, 0.8 mm.
Reference numerals 10a and 10b are exhaust pipes, and the gas in the vacuum vessel 1 is discharged by a vacuum pump (not shown).
Reference numeral 11 denotes a substrate to be plasma-processed. The substrate 11 is placed on the ground electrode 3 by opening and closing a gate valve (not shown). Then, it is heated and maintained at a predetermined temperature by a substrate heater (not shown).

  The pressure in the vacuum vessel 1 is monitored by a pressure gauge (not shown), and is automatically adjusted and set to a predetermined value by a pressure adjustment valve (not shown). In this embodiment, when the discharge gas has a flow rate of about 200 sccm to 1,500 sccm, the pressure can be adjusted to about 0.01 Torr to 10 Torr (1.33 Pa to 1,330 Pa). The vacuum ultimate pressure of the vacuum vessel 1 is about 2 to 3E-7 Torr (2.66 to 3.99E-5 Pa).

Reference numeral 25 denotes a high-frequency oscillator that generates a sine wave signal having a frequency of 10 MHz to 30 MHz (HF band) or 30 MHz to 300 MHz (VHF band), for example, a 60 MHz sine wave signal.
Reference numeral 26 denotes a power amplifier that amplifies the output of the upstream high-frequency transmitter 25. For example, the output is in the range of 0.5 to 10 KW, and power of an arbitrary magnitude is adjusted and output. The output is transmitted to an impedance matching unit 27 described later by a coaxial cable. The power amplifier 26 is provided with a power value monitor of a traveling wave and a reflected wave (not shown), and the values of the traveling wave and the reflected wave power output from the power amplifier 26 can be known.
Reference numeral 27 is an impedance matching unit that matches the output impedance of the upstream power amplifier 26 with the impedance of the downstream load. The impedance between the electrodes 2 and 3 depends on the structure of the electrode, the type of discharge gas, the pressure, etc., but there are many unclear points. The output of the impedance matching unit 27 is supplied to the electrodes 2 and 3 via the coaxial cable 28, the first balance-unbalance conversion device 4 described later, and the connection lines 35 and 36. It should be noted that the reflected wave of the supplied power is generated upstream of the impedance matching unit 27 as much as possible by using the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26 in combination. It can be reduced. However, it is generally difficult to make the reflected wave zero.
Here, as the impedance matching device 27, an unbalanced impedance matching device is used from the viewpoint of manufacturing cost and ease of use in application, but a balanced impedance matching device is used in terms of an electric circuit. It may be used.
Reference numeral 31 is a balanced transmission type current introduction terminal. The balanced-transmission-type current introduction terminal 31 is a current introduction terminal in which two or two conductors are attached to a tubular conductor via a dielectric. For example, the current introduction terminal described in Japanese Patent Application Laid-Open No. 2008-294465 can transmit power in a balanced manner. An output of a first balance-unbalance conversion device 4 to be described later is connected to the input side of the current introduction terminal 31, and connection lines 35 and 36 are connected to the output side.

Reference numeral 4 denotes a first transformer-type balanced / unbalanced converter, and power transmitted from the upstream side via the coaxial cable 28 is supplied to a first transformer-type balanced / unbalanced converter 33 (to be described later) and a first current introduction. This is supplied to the electrodes 2 and 3 via the terminal 31 and the connection lines 35 and 36. The first balance-unbalance conversion device 4 includes a cylindrical body 4 a, a lid 4 b, a coaxial cable 28, a first balance-unbalance converter 33, and a current introduction terminal 31.
Reference numeral 33 denotes a first transformer type balanced / unbalanced converter, which is a coaxial cable 28, a coaxial cable winding start portion 29 a described later, a toroidal core 30, a winding portion 29 that is a part of the coaxial cable 28, It is comprised by the winding end part 29b of the below-mentioned coaxial cable. Note that the temperature is set to an arbitrary value in the range of 50 ° C. to 150 ° C., for example, 80 degrees by a toroidal core temperature control device (not shown) that controls the temperature of the toroidal core 30 to be equal to or lower than the Curie temperature.
The material of the toroidal core 30 is, for example, a carbonyl iron (Fe (Co) 5) system having a magnetic permeability of 10 or less, a manganese / zinc (Mn—Zn) system, or a nickel / zinc (Ni—Zn) system.

2 and 3, the core wire of the winding start portion 29 a that is a part of the coaxial cable 28 of the first transformer type unbalanced transducer 33 and the core wire of the winding end portion 29 b that is a part of the coaxial cable 28 are as follows. The direction of the core wires is set so as to have a relationship of about 90 degrees. This means that an angle of about 90 degrees is set between the core wire of the winding start portion 29a and the core wire of the winding end portion 29b. As shown in FIG. 3, the coaxial cable wound on the toroidal core 30 is wound with about 1 to 6 windings. The method of winding the coaxial cable shown in FIG. 3 is referred to herein as bifilar winding.
Note that the trifiler winding, which is well known in the field of wireless engineering, may be wound, but the winding method is complicated, and thus the description is omitted here.

  However, since it is difficult to predict the optimum inductance and mutual inductance in the production of the first transformer-type balanced / unbalanced converter 33, the number of turns is set to 1 to 6, and 1 to 6 turns in advance. Prepare one with a different length.

Here, for example, one piece of one volume having different lengths, for example, one piece of 115 cm and 88 cm (length equal to a quarter of the wavelength), and one of two volumes having different lengths are used. One by one, for example 115 cm and 88 cm (length equal to one quarter of the wavelength), one by one with three different lengths, for example 115 cm and 88 cm (quarter wavelength) (One length equal to one), one each with four different lengths, for example, one with 115 cm and 88 cm (length equal to one quarter of the wavelength), one long 1 each of 5 volumes of different lengths, for example 115 cm and 88 cm (length equal to one quarter wavelength), 1 of 6 volumes of different lengths, for example about 115cm and about 88cm (length equal to a quarter of the wavelength) , It is prepared.
Then, as will be described later, the plasma is actually generated using them, and the optimum result is selected by comparing the results.

The specifications of the first transformer-type balanced / unbalanced converter 33 produced in the above 1 to 6 volumes are roughly as follows. The concept of the first transformer type balun converter 33 is as shown in FIG.
A coaxial cable having a winding number of 1 and a coaxial cable length of 114 cm (referred to herein as the first transformer type balanced / unbalanced converter 33-1). The toroidal core 30 is, for example, FT-240 manufactured by Amidon. (Permeability 40, outer diameter 61.0 mm × inner diameter 35.6 mm × height 12.7 mm), the coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U, and the length is an arbitrary value, for example, 114 cm. The winding method is bifilar winding using a wire rod for a coaxial cable.
A coaxial cable having one winding and a coaxial cable length of 87.5 cm (referred to herein as the first transformer type balanced / unbalanced converter 33-1-a)... FT-240 (magnetic permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28 and 29 are, for example, coaxial cable RG-188A / U, and the length is 87.5 cm. The length 87.5 cm is equal to a quarter of the wavelength when propagating in the coaxial cable of a radio wave having a power frequency of 60 MHz to be used (wavelength reduction rate: 70%). The winding method is bifilar winding.

A coaxial cable having two turns and a coaxial cable length of 114 cm (referred to herein as the first transformer type balanced / unbalanced converter 33-2). The toroidal core 30 is, for example, FT-240 manufactured by Amidon. (Permeability 40, outer diameter 61.0 mm × inner diameter 35.6 mm × height 12.7 mm), the coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U, and the length is an arbitrary value, for example, 114 cm. The winding method is bifilar winding using a wire rod for a coaxial cable.
A coaxial cable having two turns and a coaxial cable length of 87.5 cm (referred to here as the first transformer type balanced / unbalanced converter 33-2-a). FT-240 (magnetic permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28 and 29 are, for example, coaxial cable RG-188A / U, and the length is 87.5 cm. The length 87.5 cm is equal to a quarter of the wavelength when propagating in the coaxial cable of a radio wave having a power frequency of 60 MHz to be used (wavelength reduction rate: 70%). The winding method is bifilar winding.

A coaxial cable having three turns and a coaxial cable length of 114 cm (referred to here as the first transformer type balanced / unbalanced converter 33-3). The toroidal core 30 is, for example, FT-240 manufactured by Amidon. (Permeability 40, outer diameter 61.0 mm × inner diameter 35.6 mm × height 12.7 mm), the coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U, and the length is an arbitrary value, for example, 114 cm. The winding method is bifilar winding using a wire rod for a coaxial cable.
A coaxial cable having a winding number of 3 and a coaxial cable length of 87.5 cm (herein referred to as a first transformer type balanced / unbalanced converter 33-3-a)... FT-240 (permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U and have a length of 87.5 cm. . The length 87.5 cm is equal to a quarter of the wavelength when propagating in the coaxial cable of a radio wave having a power frequency of 60 MHz to be used (wavelength reduction rate: 70%). The winding method is bifilar winding.

A coaxial cable having four turns and a coaxial cable length of 114 cm (referred to herein as the first transformer type balanced / unbalanced converter 33-4). The toroidal core 30 is, for example, FT-240 manufactured by Amidon. (Permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), the coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U, and the length is an arbitrary value, for example, 114 cm. The winding method is bifilar winding using a wire rod for a coaxial cable.
A coaxial cable having 4 turns and a coaxial cable length of 87.5 cm (herein referred to as a first transformer-type balanced / unbalanced converter 33-4-a)... FT-240 (permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U, and the length is 87.5 cm. . The length 87.5 cm is equal to a quarter of the wavelength when propagating in the coaxial cable of a radio wave having a power frequency of 60 MHz to be used (wavelength reduction rate: 70%). The winding method is bifilar winding.

Coaxial cable having 5 turns and a coaxial cable length of 114 cm (herein referred to as first transformer type balanced / unbalanced converter 33-5). The toroidal core 30 is, for example, FT-240 manufactured by Amidon. (Permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), the coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U, and the length is an arbitrary value, for example, 114 cm. The winding method is bifilar winding using a wire rod for a coaxial cable.
Coaxial cable with 5 turns and a coaxial cable length of 87.5 cm (herein referred to as first transformer type balanced / unbalanced converter 33-5-a)... FT-240 (permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U, and the length is 87.5 cm. . The length 87.5 cm is equal to a quarter of the wavelength when propagating in the coaxial cable of a radio wave having a power frequency of 60 MHz to be used (wavelength reduction rate: 70%). The winding method is bifilar winding.

A coaxial cable having 6 turns and a coaxial cable length of 114 cm (referred to here as the first transformer type balanced / unbalanced converter 33-6). The toroidal core 30 is, for example, FT-240 manufactured by Amidon. (Permeability 40, outer diameter 61.0 mm × inner diameter 35.6 mm × height 12.7 mm), the coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U, and the length is an arbitrary value, for example, 114 cm. The winding method is bifilar winding using a wire rod for a coaxial cable.
A coaxial cable having 6 turns and a coaxial cable length of 87.5 cm (herein referred to as a first transformer-type balanced / unbalanced converter 33-6-a)... FT-240 (permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28 and 29 are, for example, coaxial cables RG-188A / U and have a length of 87.5 cm. . The length 87.5 cm is equal to a quarter of the wavelength when propagating in the coaxial cable of a radio wave having a power frequency of 60 MHz to be used (wavelength reduction rate: 70%). The winding method is bifilar winding.

  When the first balance-unbalance conversion device 4 shown in FIG. 2 is used in the plasma surface treatment apparatus (plasma CVD apparatus) provided with the transformer-type balance-unbalance conversion device according to the first embodiment shown in FIG. 4 and FIG. 5, the output of the impedance matching device 27, that is, the high frequency power supply (high frequency transmitter 25 and power amplifier 26) supplied to the electrodes 2 and 3 via the impedance matching device 27 and the coaxial cable 28. The output passes through a line composed of the core wire 29c and the outer conductor 29d of the winding portion 29 which is a part of the coaxial cable 28 which is a component of the first transformer type balun converter 33, and the output side core wire 29e, It is supplied to the electrodes 2 and 3 via the external conductor 29f, the connection line 35 and the connection line 36.

Since the first transformer-type balanced / unbalanced converter 33 has a function of an isolation transformer, the current Ix flowing through the ground shown in FIGS. The effect of allowing the current I flowing through to pass through can be exhibited. Note that the differential current is a transmission mode in which, in a power transmission circuit composed of two conductors, the amplitudes of currents flowing through both lines as the forward path and the return path are equal and the phases are 180 ° different. Here, the current Ix flowing through the ground is referred to as an in-phase current Ix or a leakage current.
4 and 5, the current I flowing through the core wire 28a of the coaxial cable 28 and the outer conductor 28b of the input portion of the first transformer type balun converter 33 flows in the form of a differential current. Similarly, the current I flowing through the core wire 29e of the coaxial cable 28 at the output portion of the first transformer type balun converter 33 and the outer conductor 29f flows in the form of a differential current. A current I flowing through the core wire 29e of the coaxial cable 28 and the outer conductor 29f flows through the connection lines 35 and 36 for supplying power to the electrodes 2 and 3.
This is because the common-mode current Ix (shown by the symbol Ix in FIGS. 4 and 5) flowing through the member of the vacuum vessel 1 connected to the ground electrode 3 is converted by the first transformer type balun converter 33. It means that it is blocked and does not flow. That is, the power to the electrodes 2 and 3 supplied via the impedance matching device 27 and the first transformer type balun converter 33 is not the current I in the form of the differential current shown in FIGS. Means no.

  Therefore, it is possible to suppress the common-mode current Ix, that is, the leakage current shown in FIGS. This means that it is possible to suppress the generation of leakage current, which is a cause of plasma generation other than between the pair of electrodes 2 and 3.

Next, when the amorphous Si for an a-Si solar cell is formed using the plasma surface treatment apparatus having the above-described configuration, a characteristic selection test (selection process) of the first transformer type unbalanced converter 33 that is performed in advance Will be described.
Here, specifically, the following 12 first transformer type unbalanced converters 33-1, 33-1-a, 33-2, 33-2-a, 33-3, 33- 3-a, 33-4, 33-4-a, 33-5, 33-5-a, 33-6, 33-6-a suitable for the following amorphous Si film formation conditions Select what you have.
The film formation conditions for amorphous Si are as follows.
(Film forming conditions)
Discharge gas: SiH4, H2 (SiH4 / H2 = 1.3)
● Flow rate: SiH4: 200 sccm, H2: 154 sccm,
● Pressure: 0.5 Torr (66.5 Pa),
● Electrode size: 40cm x 20cm,
● Electrode spacing: 2.5cm,
● Power supply frequency: 60 MHz
● Power: 300W
-Substrate temperature: 180 ° C.

The characteristic selection test (referred to as a selection process) of the first transformer-type balanced / unbalanced converter 33 adapted to the amorphous Si film-forming conditions is first described. First, the first transformer-type balanced / unbalanced converter 33-1 is selected. Is incorporated into the first balance-unbalance conversion device 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When the first transformer-type balanced / unbalanced converter 33-1 is used, for example, when the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is 300W at 60 MHz, for example, the traveling wave 170W, the reflected wave Data of wave 130W is obtained.

Next, the first transformer-type balanced / unbalanced converter 33-1-a is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When the first transformer-type balanced / unbalanced converter 33-1-a is used, for example, when the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is 300W at 60 MHz, for example, the traveling wave 190W , Data of reflection 110W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-2 is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface processing apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When the first transformer-type balanced / unbalanced converter 33-2 is used, for example, when the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is 300W at 60 MHz, for example, the traveling wave 220W, the reflected wave Data of wave 80W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-2-a is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When this first transformer type balanced / unbalanced converter 33-2-a is used, for example, when the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is 300 W at 60 MHz, for example, the traveling wave is 240 W. Data of reflected wave 60W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-3 is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface processing apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When the first transformer-type balanced / unbalanced converter 33-3 is used, for example, when the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is, for example, 300W at 60 MHz, the traveling wave 210W, the reflection Data of wave 90W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-3-a is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When this first transformer type balanced / unbalanced converter 33-3-a is used, for example, when the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is 300 W at 60 MHz, for example, the traveling wave is 230 W. Data of reflected wave 70W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-4 is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When the first transformer-type balanced / unbalanced converter 33-4 is used, for example, when the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is 300W at 60 MHz, for example, the traveling wave is 180 W, the reflection Data of wave 120W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-4-a is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When this first transformer type balanced / unbalanced converter 33-4-a is used, for example, when the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is 300 W at 60 MHz, for example, the traveling wave 190 W Data of reflected wave 110W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-5 is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface processing apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When the first transformer-type balanced / unbalanced converter 33-5 is used, for example, when the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is, for example, 300W at 60 MHz, the traveling wave 80W, the reflection Data of wave 220W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-5-a is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When this first transformer type balanced / unbalanced converter 33-5-a is used, for example, when the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is 300 W at 60 MHz, for example, the traveling wave is 90 W. Data of reflected wave 210W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-6 is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface processing apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When the first transformer-type balanced / unbalanced converter 33-6 is used, for example, when the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is, for example, 300W at 60 MHz, the traveling wave 40W, the reflection Data of wave 260W is obtained.

Similarly, the first transformer-type balanced / unbalanced converter 33-6-a is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface processing apparatus (plasma CVD apparatus) shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the output is the impedance matching device 27, the coaxial cable 28, the first balance-unbalance conversion device 4, and This is supplied to the electrodes 2 and 3 via connection lines 35 and 36. In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When this first transformer type balanced / unbalanced converter 33-6-a is used, for example, when the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is 300 W at 60 MHz, for example, the traveling wave 50 W Data of reflected wave 250W is obtained.

In the selection step, the twelve first transformer-type baluns 33, that is, 33-1, 33-1-a, 33-2, 33-2-a, 33-3, 33-3. -A, 33-4, 33-4-a, 33-5, 33-5-a, 33-6, 33-6-a, the output of the impedance matching unit 27 is the most in the electrodes 2 and 3 Since the first transformer type balanced / unbalanced converter 33-2-a can be used, the first transformer type balanced / unbalanced converter 33 can be supplied to the first transformer type balanced / unbalanced converter 33. It is determined that the converter 33-2-a is optimal. In this case, the output of the high frequency power source is 60 MHz, 300 W, traveling wave 240 W, and reflected wave 60 W.
Further, when the first transformer type balanced / unbalanced converter 33-3-a is used, the output of the high frequency power source is 60 MHz, 300 W, traveling wave 230 W, and reflected wave 70 W, which are also the first transformer type. It is determined that the balance-unbalance converter 33 is a sub-optimal first transformer-type balance-unbalance converter 33 candidate.
Therefore, by obtaining the above result, the specifications of the first transformer type balun converter 33 can be selected.

Next, in response to the result of the selection process of the first transformer type unbalanced converter 33, the process proceeds to the film forming process. In the above case, the first transformer-type balanced / unbalanced converter 4 includes the first transformer-type balanced / unbalanced converter 33-2-a.
The substrate 11 is set on the electrode 3 in advance, and a vacuum pump (not shown) is operated to remove the impurity gas and the like in the vacuum vessel 1. While supplying at a pressure of 0.5 Torr (66.5 Pa), high-frequency power, for example, power with a frequency of 60 MHz, for example 300 W, is supplied to the pair of electrodes 2 and 3. The substrate temperature is kept in the range of 80 to 350 ° C., for example, 180 ° C.

That is, in FIGS. 1 to 3, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is set to 300 W at 60 MHz, for example, and the impedance matching unit 27, the coaxial cable 28, And it supplies to the electrodes 2 and 3 via the connection lines 35 and 36.
By using the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26 in combination, the reflected wave of the supplied power is reduced on the upstream side of the impedance matching unit 27. Can be.
However, when viewed from the impedance matching unit 27 side, there is a load consisting of plasma generated between the first balance-unbalance conversion device 4 on the downstream side and the electrodes 2 and 3 under the amorphous Si film forming conditions. When impedance matching is not good, a certain amount of reflected wave returns. Here, as described above, the reflected wave is 60 W, that is, about 20% with respect to the output 300 W of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26.

In the film forming process, when SiH 4 gas is turned into plasma, radicals such as SiH 3, SiH 2, and SiH existing in the plasma diffuse due to a diffusion phenomenon and are adsorbed on the surface of the substrate 11. Accumulates.
It is a well-known technique that microcrystalline Si, thin-film polycrystalline Si, or the like can be formed by optimizing the flow ratio, pressure, and power of SiH4 and H2 in the film forming conditions.

Here, a-Si having a film forming speed of 1 to 2 nm / s is formed on a glass substrate 11 having a size of 40 cm × 20 cm (thickness 3 mm). The film forming conditions are as follows.
(Film forming conditions)
Discharge gas: SiH4, H2 (SiH4 / H2 = 1.3)
● Flow rate: SiH4: 200 sccm, H2: 154 sccm,
● Pressure: 0.5 Torr (66.5 Pa),
● Electrode size: 40cm x 20cm,
● Electrode spacing: 2.5cm,
● Power supply frequency: 60 MHz
● Power: 500W
-Substrate temperature: 180 ° C.

When plasma is generated under the above film forming conditions, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is transmitted to the first balance-unbalance conversion device 4 via the impedance matching device 27 and the coaxial cable 28, Since the transmitted power is supplied to the electrodes 2 and 3 through the connection line in the form of a differential current while suppressing the common-mode current, generation of leakage current that is a cause of plasma generation other than between the pair of electrodes Is suppressed.
Therefore, the effective power to the generated plasma is increased, and it is possible to realize power supply with less power loss than in the past. As a result, the film-forming speed of a-Si to be formed becomes faster than conventional. Numerically, an a-Si film can be formed at a film forming speed of 1 to 2 nm / s.

Note that, as shown in FIG. 4, in the power transmission circuit composed of two conductors, the differential type current is such that the amplitudes of the currents flowing through the two lines as the forward path and the return path are equal and the phases differ by 180 °. It is a transmission form.
The first transformer type unbalanced converter 33 used in this embodiment is a toroidal core having a permeability of about 40, and can be obtained at a low cost. In addition, by using a coaxial cable as a wire rod for winding. The winding is easy.

Moreover, it can be said that the present Example has the following characteristics on the structure of an apparatus.
1stly, the vacuum vessel provided with the exhaust system, the discharge gas supply system which supplies the gas for discharge in this vacuum vessel, the electrode which produces | generates plasma, a high frequency power supply, an impedance matching device, and a balance-unbalance converter In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, a transformer is provided as the balance-unbalance conversion apparatus. It is characterized by the arrangement of a type balance-unbalance converter.
Second, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device A plasma surface treatment apparatus that treats the surface of the substrate using the generated plasma, the apparatus comprising: a power supply system comprising: a power supply system comprising: Along the upstream side to the downstream side of the power flow, a high-frequency power source, an impedance matching device, a transformer-type balanced / unbalanced converter, and a current introduction terminal having two ungrounded conductors as power lines are arranged in this order. It is characterized by.
Third, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, the power supply system comprising: a substrate holding means for arranging the substrate to be plasma processed; It is characterized by having a transformer type balun using a coaxial cable for winding.
Fourth, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a power supply system comprising a high frequency power source and an impedance matching device, And a substrate holding means for arranging a substrate to be plasma-treated, and a plasma surface treatment apparatus for treating the surface of the substrate by using the generated plasma. A transformer is provided at a bent portion of the power transmission path inside the vacuum vessel. A type balance-unbalance converter is arranged.
Fifth, the transformer type unbalanced transducer is disposed inside the vacuum vessel.

Further, in this embodiment, since the feeding point is set to one point (a pair) at one end of the electrode in feeding power to the electrodes 2 and 3, the substrate size is limited to about 40 × 20 cm, but if the number of feeding points is increased. Of course, the size range can be expanded.
In addition, if a plurality of pairs of electrodes are installed and a plurality of the above-described power supply systems are arranged according to the number of the electrodes, it is natural that the width of the substrate size can be expanded.

In the manufacture of a-Si solar cells, thin film transistors, and photosensitive drums, there is no problem in reducing the cost of manufactured products as long as the film forming speed is 1 nm / s or more. Although the power supply frequency of 60 MHz is used in the above embodiment, it is naturally possible to use 13.56 MHz.
This means that the industrial value related to productivity improvement and cost reduction in the manufacturing field of a-Si solar cells, thin film transistors, and photosensitive drums is remarkably large.

(Example 2)
FIG. 1, FIG. 2 and FIG. 6 show a plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer type balance-unbalance conversion apparatus according to the second embodiment of the present invention. The description will be given with reference.
FIG. 6 shows a second transformer used in a plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer type balance-unbalance conversion apparatus according to the second embodiment of the present invention. It is explanatory drawing of a type | mold balance-unbalance conversion apparatus. However, although the cylindrical body 51a and the lid | cover 51b similar to the cylindrical body 4a and the lid | cover 4b which are the structural members of the 1st unbalance conversion apparatus 4 shown in FIG. 2 are required, they are not shown in FIG.

In FIG. 6, reference numeral 52 denotes a second transformer type balun. The second transformer type balanced / unbalanced converter 52 winds a part of the two coaxial cables 28-1 and 28-2 connected to the output of the impedance matching unit 27 around the toroidal core 30, and introduces current at the end thereof. It has a structure of connecting to the terminal 31.
Here, as the impedance matching device 27, an unbalanced impedance matching device is used from the viewpoint of manufacturing cost and ease of use in application, but a balanced impedance matching device is used in terms of an electric circuit. It may be used.
In FIG. 6, the impedance matching unit 27 includes, for example, a coil 40 and variable capacitance capacitors 41 and 42 connected to both ends of the coil 40. On the input side of the impedance matching unit 27, the core wire of the coaxial cable that transmits power from the upstream side is connected to one terminal of the coil 40 and one terminal of the variable capacitance capacitor 41, and the outer conductor of the coaxial cable and the capacitance The other terminal of the variable capacitor 41 is connected by a connection line 45. The outer conductor of the coaxial cable is grounded.
Further, on the output side of the impedance matching unit 27, the terminal of the variable capacitance capacitor 42 and the core wires of the coaxial cables 28-1 and 28-2 are connected. The outer conductors of the coaxial cables 28-1 and 28-2 are grounded by the connection line 44.
The second balance / unbalance converter 52 includes a cylinder 51a (not shown), a lid 51b, two coaxial cables 28-1, 28-2, a toroidal core 30, two coaxial cables 28-1, 28-2, winding start portions 28-1-a and 28-2-a, winding portions 29-1 and 29-2, winding end portions 29b-1 and 29b-2, and winding end portions that are part of 28-2 29b-1 and 29b-2 core wires 29f-1, 29f-2 and a current introduction terminal 31.
The core wires at the upstream ends of the two coaxial cables 28-1 and 28-2 are connected to the output line 43 of the impedance matching device 27, and the upstream ends of the two coaxial cables 28-1 and 28-2. The outer conductor at the end on the side is connected to the ground portion of the impedance matching unit 27 by a connection line 44.
Further, the core wires 29f-1 and 29f-2 of the winding end portions 29b-1 and 29b-2 of the coaxial cable of the second flat transformer type unbalanced converter 52 are connected to the conductor 32a of the current introduction terminal 31. The outer conductors of the winding end portions 29b-1 and 29b-2 of the coaxial cable are connected by a conductor 46 and connected to the conductor 32b of the current introduction terminal 31 through a connection line 29e.

In FIG. 6, the core wires of the winding start portions 28-1-a and 28-2-a of the toroidal 30 portion of the coaxial cables 28-1 and 28-2 of the second transformer type unbalanced transducer 52, The positional relationship of the core wires of the winding end portions 29b-1 and 29b-2 is set so that the directions of the core wires are about 90 degrees. This means that there is an angle of about 90 degrees between the core wires of the winding start portions 28-1-a and 28-2-a and the core wires of the winding end portions 29b-1 and 29b-2.
Further, as in the case of the first embodiment, the temperature is adjusted to an arbitrary value in the range of 50 ° C. to 150 ° C. by a toroidal core temperature control device (not shown) that controls the temperature of the toroidal core 30 to be equal to or lower than the Curie temperature, for example, 80 degrees. Set to
The material of the toroidal core 30 is, for example, a carbonyl iron (Fe (Co) 5) system having a magnetic permeability of 10 or less, a manganese / zinc (Mn—Zn) system, or a nickel / zinc (Ni—Zn) system.

  However, here, since it is difficult to predict the optimum inductance and mutual inductance of the coil in the production of the second transformer type balanced / unbalanced converter 52, The number of coaxial cables is 2 to 5, and the length of the coaxial cable is prepared in advance so as to have a length equal to a quarter of the wavelength of power to be used.

  That is, the specifications of the second transformer type unbalanced converter 52 are roughly as follows. Two coaxial cables with two turns and a coaxial cable length of 87.5 cm (herein referred to as a second transformer type balanced / unbalanced converter 52-2 in parallel)... Toroidal core 30 For example, FT-240 manufactured by Amidon (permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28-1, 28-2, 29-1, 29-2 are, for example, Coaxial cable RG-188A / U, the length is 87.5cm. The length 87.5 cm is equal to a quarter of the wavelength when the radio wave having a power frequency of 60 MHz used is propagated through the coaxial cable (wavelength reduction rate: 70%). The winding method is as shown in FIG.

  Three coaxial cables with two turns and a coaxial cable length of 87.5 cm (herein referred to as a second transformer type balanced / unbalanced converter 52-3 in parallel)... Toroidal core 30 For example, FT-240 manufactured by Amidon (permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28-1, 28-2, 29-1, 29-2 are, for example, Coaxial cable RG-188A / U, the length is 87.5cm. The length 87.5 cm is equal to a quarter of the wavelength when the radio wave having a power frequency of 60 MHz used is propagated through the coaxial cable (wavelength reduction rate: 70%). The winding method is as shown in FIG.

  Four coaxial cables with two turns and a coaxial cable length of 87.5 cm (herein referred to as a second transformer type balanced / unbalanced converter 52-4 in parallel)... Toroidal core 30 For example, FT-240 manufactured by Amidon (permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28-1, 28-2, 29-1, 29-2 are, for example, Coaxial cable RG-188A / U, the length is 87.5cm. The length 87.5 cm is equal to a quarter of the wavelength when the radio wave having a power frequency of 60 MHz used is propagated through the coaxial cable (wavelength reduction rate: 70%). The winding method is as shown in FIG.

  The number of coaxial cables is 5 and the number of turns is 2 and the length of the coaxial cable is 87.5 cm (herein referred to as the second transformer type balanced / unbalanced converter 52-5 in parallel)... For example, FT-240 manufactured by Amidon (permeability 40, outer diameter 61.0 mm x inner diameter 35.6 mm x height 12.7 mm), coaxial cables 28-1, 28-2, 29-1, 29-2 are, for example, Coaxial cable RG-188A / U, the length is 87.5cm. The length 87.5 cm is equal to a quarter of the wavelength when propagating through the coaxial cable of the radio wave having a power frequency of 60 MHz to be used (wavelength reduction rate: 70%). The winding method is as shown in FIG.

Next, as in the case of the first embodiment, the second transformer-type balanced / unbalanced converter 52-2 is parallel, the second transformer-type balanced / unbalanced converter 52-3 is parallel, and the second transformer-type balanced / unbalanced converter 52-2 is parallel. A selection test (referred to as a selection step) is performed for the balanced converter 52-4 in parallel and the second transformer-type balanced / unbalanced converter 52-5 in parallel. The plasma generation conditions during the selection test are as follows.
(Plasma generation conditions)
Discharge gas: SiH4, H2 (SiH4 / H2 = 1.3)
● Flow rate: SiH4: 500 sccm, H2: 384 sccm,
● Pressure: 0.5 Torr (66.5 Pa),
● Electrode size: 40cm x 20cm,
● Electrode spacing: 2.5cm,
● Power supply frequency: 60 MHz
● Power: 900W
-Substrate temperature: 180 ° C.

The characteristic selection test (referred to as a selection process) of the second transformer-type balanced / unbalanced converter 52 that conforms to the amorphous Si film-forming conditions will be described. First, the second transformer-type balanced / unbalanced converter 52-2 will be described. The parallel is incorporated in the first transformer type balance-unbalance conversion device 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. However, the impedance matching unit 27 and the second transformer type balun converter 52 are connected according to the arrangement shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1, 2, and 6, the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is set to 900 W at 60 MHz, for example, and the output is the impedance matching device 27 and the second transformer type balun converter 52. Is supplied to the electrodes 2 and 3 via the first balance-unbalance conversion device 4 and the connection lines 35 and 36.
In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When the second transformer type balanced / unbalanced converter 52-2 is used in parallel, for example, when the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is 900W at 60 MHz, the traveling wave 800W, Data of reflected wave 100W is obtained.

Next, the second transformer-type balanced / unbalanced converter 52-3 in parallel is incorporated into the first balanced / unbalanced converting apparatus 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. However, the impedance matching unit 27 and the second transformer type balun converter 52 are connected according to the arrangement shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1, 2, and 6, the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is set to 900 W at 60 MHz, for example, and the output is the impedance matching device 27 and the second transformer type balun converter 52. Is supplied to the electrodes 2 and 3 via the first balance-unbalance conversion device 4 and the connection lines 35 and 36.
In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When this second transformer type balanced / unbalanced converter 52-3 is used in parallel, for example, when the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is 900 W at 60 MHz, the traveling wave 820 W, Data of reflected wave 80W is obtained.

Similarly, the second transformer-type balanced / unbalanced converter 52-4 in parallel is incorporated in the first balanced / unbalanced converting apparatus 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. However, the impedance matching unit 27 and the second transformer type balun converter 52 are connected according to the arrangement shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1, 2, and 6, the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is set to 900 W at 60 MHz, for example, and the output is the impedance matching device 27 and the second transformer type balun converter 52. Is supplied to the electrodes 2 and 3 via the first balance-unbalance conversion device 4 and the connection lines 35 and 36.
In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When this second transformer type balanced / unbalanced converter 52-4 is used in parallel, for example, when the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is 900 W at 60 MHz, the traveling wave 840 W, Data of reflected wave 60W is obtained.

Next, the second transformer-type balanced / unbalanced converter 52-5 parallel is incorporated into the first balanced / unbalanced converting apparatus 4 of the plasma surface treatment apparatus (plasma CVD apparatus) shown in FIG. However, the impedance matching unit 27 and the second transformer type balun converter 52 are connected according to the arrangement shown in FIG. Then, a plasma generation test is performed using the plasma surface treatment apparatus (plasma CVD apparatus).
1, 2, and 6, the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is set to 900 W at 60 MHz, for example, and the output is the impedance matching device 27 and the second transformer type balun converter 52. Is supplied to the electrodes 2 and 3 via the first balance-unbalance conversion device 4 and the connection lines 35 and 36.
In addition, by using a combination of the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26, the reflected wave of the supplied power is provided upstream of the impedance matching unit 27. Can be reduced.
When the second transformer type balanced / unbalanced converter 52-5 is used in parallel, for example, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is, for example, 900W at 60 MHz, the traveling wave 850W, Data of reflected wave 50W is obtained.

By obtaining the result as described above, the specifications of the second transformer-type balun converter 52 can be selected. That is, when the data is obtained in the selection step, the optimum specification among the four second transformer-type balanced / unbalanced converters 52 is parallel to the second transformer-type balanced / unbalanced converter 52-5. It is judged. That is, when the second transformer type balanced / unbalanced converter 52-5 is used in parallel, the output of the high frequency power source is 60 MHz, 900 W, traveling wave 850 W, reflected wave 50 W, and the four second transformers. Since the number of reflected waves is the smallest in the type balance / unbalance converter 52, the most power can be supplied to the electrodes 2 and 3. Accordingly, it is determined that the second transformer type balanced / unbalanced converter 52-5 in parallel is optimal as the second transformer type balanced / unbalanced converter 52.
The above results show that the structure of the transformer-type balanced / unbalanced converter matches the output impedance of the high-frequency power supply on the upstream side with the load composed of the electrodes 2, 3 and the current introduction terminal 31 located on the downstream side of the impedance matching unit 27. It shows that it has a big influence on. In addition, when the structure of the transformer type balanced / unbalanced converter in the case of Example 1 is compared with the structure of the transformer type balanced / unbalanced converter in the case of Example 2, the major difference is the number of coaxial cables wound around the toroidal core. In the case of the second embodiment, there is a single number in the case of the second embodiment.
In addition, since a plurality of coaxial cables are arranged in parallel in terms of electrical circuit, in addition to increasing the capacity of transmission power, it is possible to reduce the impedance of the coaxial cable. . That is, the impedance of the power transmission line between the impedance matching unit 27 and the electrodes 2 and 3 is reduced, and the matching of the output impedance of the high-frequency power source with respect to the electrical load composed of the electrodes 2 and 3 and the current introduction terminal is improved. It is possible.
Further, from the above results, the characteristic impedance when, for example, a plurality of five coaxial cables are arranged in parallel as compared with the coaxial cable having a characteristic impedance of 50Ω used between the impedance matching unit 27 and the electrode is approximately Probably proportional to 1/5. That is, it is considered that the characteristic impedance of the coaxial cable arranged between the impedance matching unit 27 and the current introduction terminal should be 50Ω or less.
Incidentally, in a conventional actual thin film solar cell production factory, a single coaxial cable having a characteristic impedance of 50Ω is used for supplying plasma generation power, and in general, an idea of arranging a plurality of coaxial cables in parallel is used. There seems to be no.

Next, in response to the result of the selection process of the second transformer type unbalanced converter 52, the process proceeds to the film forming process. In the above case, the first transformer-type balanced / unbalanced converter 4 incorporates the second transformer-type balanced / unbalanced converter 52-5 in parallel. However, the impedance matching unit 27 and the second transformer type balun converter 52 are connected according to the arrangement shown in FIG.
The substrate 11 is set on the electrode 3 in advance, and a vacuum pump (not shown) is operated to remove impurity gas and the like in the vacuum vessel 1. While supplying at 5 Torr (66.5 Pa), high-frequency power, for example, power with a frequency of 60 MHz, for example, 900 W is supplied to the pair of electrodes 2 and 3. The substrate temperature is kept in the range of 80 to 350 ° C., for example, 180 ° C.

That is, in FIG. 1, FIG. 2 and FIG. 6, the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is, for example, 60 MHz 900 W. And it supplies to the electrodes 2 and 3 via the connection lines 35 and 36.
By using the LC regulator of the impedance matching unit 27 and the power value monitor of the traveling wave and the reflected wave attached to the power amplifier 26 in combination, the reflected wave of the supplied power is reduced on the upstream side of the impedance matching unit 27. Can be.
However, impedance matching between the output impedance of the high-frequency power supply and the load made of plasma generated between the second transformer-type unbalanced converter 52 and the electrodes 2 and 3 on the downstream side of the impedance matching device 27. If it is not good, a certain amount of reflected waves will return. Here, as described above, the reflected wave is 50 W, that is, about 6% with respect to the output 900 W of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26.

In the film forming process, when SiH 4 gas is turned into plasma, radicals such as SiH 3, SiH 2, and SiH existing in the plasma diffuse due to a diffusion phenomenon and are adsorbed on the surface of the substrate 11. Accumulates.
It is a well-known technique that microcrystalline Si, thin-film polycrystalline Si, or the like can be formed by optimizing the flow ratio, pressure, and power of SiH4 and H2 in the film forming conditions.

Here, a-Si having a film forming speed of 1 to 2 nm / s is formed on a glass substrate 11 having a size of 40 cm × 20 cm (thickness 3 mm). The film forming conditions are as follows.
(Film forming conditions)
Discharge gas: SiH4, H2 (SiH4 / H2 = 1.3)
● Flow rate: SiH4: 500 sccm, H2: 384 sccm,
● Pressure: 0.5 Torr (66.5 Pa),
● Electrode size: 40cm x 20cm,
● Electrode spacing: 2.5cm,
● Power supply frequency: 60 MHz
● Power: 900W
-Substrate temperature: 180 ° C.

When plasma is generated under the above-mentioned film forming conditions, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 is the first in which the impedance matching unit 27 and the second transformer type balun converter 52-3 are incorporated in parallel. The power having the differential current form shown in FIG. 4 is supplied to the electrodes 2 and 3 via the current introduction terminal 31 and the connection lines 35 and 36 via the transformer type balance-unbalance conversion device 4. Since the electric power supplied to the electrodes 2 and 3 is in the form of a differential current in which the common-mode current is suppressed, generation of leakage current that is a cause of plasma generation other than between the pair of electrodes is suppressed.
Therefore, the effective power to the generated plasma is increased, and it is possible to realize power supply with less power loss than in the past. As a result, the film-forming speed of a-Si to be formed becomes faster than conventional. Numerically, an a-Si film can be formed at a film forming speed of 2 to 4 nm / s.

As shown in FIGS. 4 and 5, the differential current is the same in the power transmission circuit composed of two conductors, the amplitude of the current flowing in both the forward path and the return path is equal, and the phase is 180. ° Different transmission modes.
Further, the second transformer type unbalanced converter 52 used in this embodiment is a toroidal core having a magnetic permeability of about 40. In addition to being available at a low cost, a coaxial cable is used as a winding wire. The winding is easy.
In addition, since a plurality of coaxial cables are used in the second transformer-type balanced / unbalanced converter 52, even when a thin coaxial cable that can be easily wound around the toroidal core is used, transmission can be increased by increasing the number of coaxial cables. The capacity of possible power can be easily increased.
Therefore, the effective power to the generated plasma is increased and the capacity of the supplied power can be increased, so that it is possible to realize power supply with less power loss as compared with the prior art.

Moreover, it can be said that the present Example has the following characteristics on the structure of an apparatus.
1stly, the vacuum vessel provided with the exhaust system, the discharge gas supply system which supplies the gas for discharge in this vacuum vessel, the electrode which produces | generates plasma, a high frequency power supply, an impedance matching device, and a balance-unbalance converter In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, a transformer is provided as the balance-unbalance conversion apparatus. It is characterized by the arrangement of a type balance-unbalance converter.
Second, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device A plasma surface treatment apparatus that treats the surface of the substrate using the generated plasma, the apparatus comprising: a power supply system comprising: a power supply system comprising: Along the upstream side to the downstream side of the power flow, a high-frequency power source, an impedance matching device, a transformer-type balanced / unbalanced converter, and a current introduction terminal having two ungrounded conductors as power lines are arranged in this order. It is characterized by.
Third, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, the power supply system comprising: a substrate holding means for arranging the substrate to be plasma processed; It is characterized by having a transformer type balun using a coaxial cable for winding.
Fourth, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a power supply system comprising a high frequency power source and an impedance matching device, And a substrate holding means for arranging a substrate to be plasma-treated, and a plasma surface treatment apparatus for treating the surface of the substrate by using the generated plasma. A transformer is provided at a bent portion of the power transmission path inside the vacuum vessel. A type balance-unbalance converter is arranged.
Fifth, the transformer type unbalanced transducer is disposed inside the vacuum vessel.
Sixth, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, the power supply system comprising: a substrate holding means for arranging the substrate to be plasma processed; One toroidal core and a plurality of coaxial cables are used for the winding wound around the toroidal core, and a transformer-type balanced / unbalanced converter in which they are connected in parallel is arranged.

Further, in this embodiment, since the feeding point is set to one point (a pair) at one end of the electrode in feeding power to the electrodes 2 and 3, the substrate size is limited to about 40 × 20 cm, but if the number of feeding points is increased. Of course, the size range can be expanded.
In addition, if a plurality of pairs of electrodes are installed and a plurality of the above-described power supply systems are arranged according to the number of the electrodes, it is natural that the width of the substrate size can be expanded.

In the manufacture of a-Si solar cells, thin film transistors, and photosensitive drums, there is no problem in reducing the cost of manufactured products as long as the film forming speed is 1 nm / s or more. The film forming speed of 2 to 4 nm / s is a film forming speed that is not achieved in the actual production factory in the prior art.
Although the power supply frequency of 60 MHz is used in the above embodiment, it is naturally possible to use 13.56 MHz.
This means that the industrial value related to productivity improvement and cost reduction in the manufacturing field of a-Si solar cells, thin film transistors, and photosensitive drums is remarkably large.

(Example 3)
A plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer-type balance-unbalance conversion apparatus according to the third embodiment of the present invention will be described with reference to FIGS. explain.
FIG. 7 shows a third transformer used in a plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer type balance-unbalance conversion apparatus according to the third embodiment of the present invention. It is explanatory drawing of a type | mold balance-unbalance conversion apparatus.
The third transformer-type balance-unbalance conversion device shown in FIG. 7 includes the impedance matching unit 27 and the first component of the plasma surface treatment apparatus (plasma CVD device) provided with the transformer-type balance-unbalance conversion device shown in FIG. The transformer type balance-unbalance conversion device 4 is used instead. That is, the impedance matching unit 27 and the first transformer type balance-unbalance conversion device are integrated, and the practicality can be improved.
In addition, it is assumed that the attachment position of the third transformer type unbalanced conversion apparatus to the plasma CVD apparatus is the wall of the vacuum vessel 1 facing the length direction of the electrodes 2 and 3.
Here, an unbalanced impedance matching device is used for the impedance matching device 27 from the viewpoint of manufacturing cost and ease of use in application, but in terms of electric circuit, a balanced impedance matching device is used. A vessel may be used.

In FIG. 7, reference numeral 73 denotes a cylinder of the third transformer type balun. The cylindrical body 73 is provided with the same components as the impedance matching unit 27 and a third transformer type balanced / unbalanced converter 74 similar to the transformer type balanced / unbalanced conversion apparatus used in the first and second embodiments. Is arranged.
In FIG. 7, the impedance matching unit 27 includes, for example, a coil 40 and variable capacitance type capacitors 41 and 42 connected to both ends of the coil 40 as shown in FIG. On the input side of the impedance matching unit 27, the core of the coaxial cable that transmits power from the upstream side is connected to one terminal of the coil 40 and one terminal of the variable capacitance capacitor 41, and the outer conductor of the coaxial cable. And the other terminal of the variable capacitance capacitor 41 is connected by a connection line 45. The outer conductor of the coaxial cable is grounded through the cylindrical body 73.
The part of the third transformer type balanced / unbalanced converter 74 wraps a part of the two coaxial cables 28-1 and 28-2 connected to the output of the part of the impedance matching unit 27 around the toroidal core 30. The output side is connected to the current introduction terminal 31.
The core wires 29f-1 and 29f-2 of the winding end portions 29b-1 and 29b-2 of the coaxial cable of the transformer type unbalanced converter are connected to the conductor 32a of the current introduction terminal 31, and the coaxial cable is connected. The outer conductors of the winding end portions 29b-1 and 29b-2 are connected by a conductor 46 and connected to the conductor 32b of the current introduction terminal 31 through a connection line 29e.

  The third transformer type unbalanced conversion device shown in FIG. 7 is a device in which the impedance matching unit 27 and the transformer type balanced / unbalanced conversion device are integrated, but the third transformer type balanced / unbalanced component of the device is the same. Since the balanced converter 74 has the function of an isolation transformer, the leakage current Ix that flows through the ground is cut off and the current I that flows in the form of a differential current, as in the first embodiment. It is possible to exert the effect of passing the. Note that the differential current is a transmission mode in which, in a power transmission circuit composed of two conductors, the amplitudes of currents flowing through both lines as the forward path and the return path are equal and the phases are 180 ° different. Therefore, it is possible to suppress the leakage current Ix that causes a problem in the prior art. That is, it means that it is possible to suppress the generation of leakage current, which is a cause of plasma generation except between the pair of electrodes 2 and 3.

  FIG. 7 shows a specific application of the third transformer-type balanced-unbalanced conversion apparatus. As shown in the first and second embodiments, the third transformer-type balanced-unbalanced is applied to each individual application. A selection process is required to select specific specifications for the converter. And based on the result of this selection process, it applies to a film-forming test. However, since it is the same as that of Example 1 and Example 2, description is abbreviate | omitted here.

When the plasma is generated by using the third transformer type balanced / unbalanced conversion device shown in FIG. 7, the output of the high frequency power source composed of the high frequency transmitter 25 and the power amplifier 26 becomes the impedance matching unit 27 and the third transformer type balanced / unbalanced. The power having the differential current form shown in FIG. 4 is supplied to the electrode 2 through the current introduction terminal 31 and the connection lines 35 and 36 through the third transformer type unbalanced conversion device incorporating the converter 74. 3 is supplied. Since the power supplied to the electrodes 2 and 3 is in the form of a differential current in which the leakage current is suppressed, the generation of leakage current that is a cause of plasma generation other than between the pair of electrodes is suppressed.
Further, since a plurality of thin coaxial cables that can be easily wound around the toroidal core are used for the windings of the third transformer type unbalanced converter 74, the capacity of power that can be transmitted can be increased by increasing the number of the coaxial cables. Can be easily increased.
Therefore, the effective power to the generated plasma is increased and the capacity of the supplied power can be increased, so that it is possible to realize power supply with less power loss as compared with the prior art. As a result, the film-forming speed of a-Si to be formed becomes faster than that of the prior art. Numerically, an a-Si film can be formed at a film forming speed of 2 to 4 nm / s.

As shown in FIGS. 4 and 5, the differential current is the same in the power transmission circuit composed of two conductors, the amplitude of the current flowing in both the forward path and the return path is equal, and the phase is 180. ° Different transmission modes.
Further, the second transformer type unbalanced converter 52 used in this embodiment is a toroidal core having a magnetic permeability of about 40. In addition to being available at a low cost, a coaxial cable is used as a winding wire. The winding is easy.

Moreover, it can be said that the present Example has the following characteristics on the structure of an apparatus.
1stly, the vacuum vessel provided with the exhaust system, the discharge gas supply system which supplies the gas for discharge in this vacuum vessel, the electrode which produces | generates plasma, a high frequency power supply, an impedance matching device, and a balance-unbalance converter In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, a transformer is provided as the balance-unbalance conversion apparatus. It is characterized by the arrangement of a type balance-unbalance converter.
Second, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device A plasma surface treatment apparatus that treats the surface of the substrate using the generated plasma, the apparatus comprising: a power supply system comprising: a power supply system comprising: Along the upstream side to the downstream side of the power flow, a high-frequency power source, an impedance matching device, a transformer-type balanced / unbalanced converter, and a current introduction terminal having two ungrounded conductors as power lines are arranged in this order. It is characterized by.
Third, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, the power supply system comprising: a substrate holding means for arranging the substrate to be plasma processed; It is characterized by having a transformer type balun using a coaxial cable for winding.

(Example 4)
A plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer type balance-unbalance conversion apparatus according to the fourth embodiment of the present invention will be described with reference to FIGS. explain.
FIG. 8 shows a fourth transformer used in a plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer type balance-unbalance conversion apparatus according to the fourth embodiment of the present invention. It is explanatory drawing of a type | mold balance-unbalance conversion apparatus.
The fourth transformer-type balanced / unbalanced conversion apparatus shown in FIG. 8 includes the impedance matching unit 27 and the first component of the plasma surface processing apparatus (plasma CVD apparatus) provided with the transformer-type balanced / unbalanced conversion apparatus shown in FIG. The transformer type balance-unbalance conversion device 4 is used instead. In other words, the impedance matching unit 27 and the transformer-type balance-unbalance conversion device part are integrated, and the practicality can be improved.
In addition, it is assumed that the mounting position of the fourth transformer-type balanced / unbalanced conversion apparatus to the plasma CVD apparatus is the wall of the vacuum vessel 1 facing the length direction of the electrodes 2 and 3.
Here, as the impedance matching device 27, an unbalanced impedance matching device is used from the viewpoint of manufacturing cost and ease of use in application, but a balanced impedance matching device is used in terms of an electric circuit. It may be used.

In FIG. 8, reference numeral 73 denotes a cylinder of the fourth transformer-type balun. The cylindrical body 73 is provided with the same components as the impedance matching device 27, and a fourth transformer-type balanced / unbalanced converter 75 similar to the transformer-type balanced / unbalanced conversion device used in the first and second embodiments. Is arranged.
In FIG. 8, the impedance matching unit 27 includes, for example, a coil 40 and variable capacitance capacitors 41 and 42 connected to both ends of the coil 40 as shown in FIG. On the input side of the impedance matching unit 27, the core of the coaxial cable that transmits power from the upstream side is connected to one terminal of the coil 40 and one terminal of the variable capacitance capacitor 41, and the outer conductor of the coaxial cable. And the other terminal of the variable capacitance capacitor 41 is connected by a connection line 45. The outer conductor of the coaxial cable is grounded through the cylindrical body 73.
The part of the fourth transformer type balanced / unbalanced converter 75 is connected to the output of the part of the impedance matching unit 27, for example, a part of two coaxial cables, and two toroidal cores 30-1, 30. -2 is wound separately, and the output side thereof is connected to the current introduction terminal 31.
The core wires 29f-1 and 29f-2 of the winding end portions 29b-1 and 29b-2 of the coaxial cable of the transformer type unbalanced converter are connected to the conductor 32a of the current introduction terminal 31, and the coaxial cable is connected. The outer conductors of the winding end portions 29b-1 and 29b-2 are connected by a conductor 46 and connected to the conductor 32b of the current introduction terminal 31 through a connection line 29e.

  8 is an apparatus in which the impedance matching unit 27 and the transformer-type balance-unbalance conversion apparatus are integrated. The fourth transformer-type balance-unbalance apparatus shown in FIG. Since the balanced converter 75 has the function of an isolation transformer, the leakage current Ix that flows through the ground is cut off and the current I that flows in the form of a differential current, as in the first embodiment. It is possible to exert the effect of passing the. Note that the differential current is a transmission mode in which, in a power transmission circuit composed of two conductors, the amplitudes of currents flowing through both lines as the forward path and the return path are equal and the phases are 180 ° different. Therefore, it is possible to suppress the leakage current Ix that causes a problem in the prior art. That is, it means that it is possible to suppress the generation of leakage current, which is a cause of plasma generation except between the pair of electrodes 2 and 3.

  FIG. 8 shows a specific application of the fourth transformer-type balanced / unbalanced converter. As shown in the first and second embodiments, the transformer-type balanced / unbalanced converter 75 is used for each application. A selection process to select specific specifications is required. And based on the result of this selection process, it applies to a film-forming test. However, since it is the same as that of Example 1 and Example 2, description is abbreviate | omitted here.

When the plasma is generated by using the fourth transformer-type balanced / unbalanced conversion device shown in FIG. 8, the output of the high-frequency power source composed of the high-frequency transmitter 25 and the power amplifier 26 is the impedance matching device 27 and the fourth transformer-type balanced / unbalanced. The power having the differential current form shown in FIG. 4 is supplied to the electrode 2 via the current introduction terminal 31 and the connection lines 35 and 36 through the fourth transformer type unbalanced conversion device incorporating the converter 75. 3 is supplied. Since the power supplied to the electrodes 2 and 3 is in the form of a differential current in which the leakage current is suppressed, the generation of leakage current that is a cause of plasma generation other than between the pair of electrodes is suppressed.
In addition, since the fourth transformer type unbalanced converter 74 uses a plurality of toroidal cores and a plurality of coaxial cables, the number is increased even when a thin coaxial cable that can be easily wound around the toroidal core is used. By doing so, the capacity of power that can be transmitted can be easily increased.
Therefore, the effective power to the generated plasma is increased and the capacity of the supplied power can be increased, so that it is possible to realize power supply with less power loss as compared with the prior art. As a result, the film-forming speed of a-Si to be formed becomes faster than that of the prior art. Numerically, an a-Si film can be formed at a film forming speed of 2 to 4 nm / s.

As shown in FIGS. 4 and 5, the differential current is the same in the power transmission circuit composed of two conductors, the amplitude of the current flowing in both the forward path and the return path is equal, and the phase is 180. ° Different transmission modes.
Further, the second transformer type unbalanced converter 52 used in this embodiment is a toroidal core having a magnetic permeability of about 40. In addition to being available at a low cost, a coaxial cable is used as a winding wire. The winding is easy.

Moreover, it can be said that the present Example has the following characteristics on the structure of an apparatus.
1stly, the vacuum vessel provided with the exhaust system, the discharge gas supply system which supplies the gas for discharge in this vacuum vessel, the electrode which produces | generates plasma, a high frequency power supply, an impedance matching device, and a balance-unbalance converter In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, a transformer is provided as the balance-unbalance conversion apparatus. It is characterized by the arrangement of a type balance-unbalance converter.
Second, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device A plasma surface treatment apparatus that treats the surface of the substrate using the generated plasma, the apparatus comprising: a power supply system comprising: a power supply system comprising: Along the upstream side to the downstream side of the power flow, a high-frequency power source, an impedance matching device, a transformer-type balanced / unbalanced converter, and a current introduction terminal having two ungrounded conductors as power lines are arranged in this order. It is characterized by.
Third, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, the power supply system comprising: a substrate holding means for arranging the substrate to be plasma processed; It is characterized by having a transformer type balun using a coaxial cable for winding.
Fourth, a vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device In the plasma surface processing apparatus for processing the surface of the substrate using the generated plasma, the power supply system comprising: a substrate holding means for arranging the substrate to be plasma processed; A plurality of transformer-type balanced / unbalanced converters each composed of one toroidal core and one coaxial cable are arranged, and the plurality of transformer-type balanced / unbalanced converters are connected in parallel.

FIG. 1 is a schematic view showing the entirety of a plasma surface treatment apparatus (plasma CVD apparatus) provided with a transformer type balance-unbalance conversion apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing the entire first transformer-type balanced-unbalanced conversion apparatus according to the first embodiment of the present invention. FIG. 3 is an explanatory diagram relating to the structure of a first balanced / unbalanced converter, which is a component of the first transformer-type balanced / unbalanced converter shown in FIG. FIG. 4 is an explanatory diagram relating to a basic electric circuit of the first transformer-type balance-unbalance conversion device shown in FIG. FIG. 5 is an explanatory diagram relating to an electric circuit of the first transformer type balun. FIG. 6 shows a second transformer type used in a plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer type balance-unbalance conversion apparatus according to the second embodiment of the present invention. Explanatory drawing of a balance-unbalance conversion apparatus. FIG. 7 shows a third transformer type used in a plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer type balance-unbalance conversion apparatus according to the third embodiment of the present invention. Explanatory drawing of a balance-unbalance conversion apparatus. FIG. 8 shows a fourth transformer type used in a plasma surface treatment apparatus (plasma CVD apparatus) and a plasma surface treatment method (plasma CVD method) provided with a transformer type balance-unbalance conversion apparatus according to the fourth embodiment of the present invention. Explanatory drawing of a balance-unbalance conversion apparatus. FIG. 9 is a conceptual diagram of the structure of an atmospheric coaxial cable having an L-shaped bent portion. FIG. 10 is a conceptual diagram of the structure of a vacuum coaxial cable having an L-shaped bent portion. FIG. 11 is an explanatory view showing the concept of leakage current generated in a conventional plasma surface treatment apparatus.

1 ... Vacuum container,
2 ... Ungrounded electrode,
3 ... Ground electrode,
4 ... Transformer balance-unbalance conversion device,
5a, 5b ... insulator support material,
6 ... discharge gas mixing box,
7 ... Rectifying plate,
8: Gas supply pipe,
9: Gas ejection hole,
10a, 10b ... exhaust pipe,
11 ... substrate
25 ... Transmitter,
26: Power amplifier,
27: Impedance matching device,
28 ... Coaxial cable,
30 ... Tridal core 31 ... Current introduction terminal,
33: A first transformer-type balanced-unbalanced converter.

Claims (11)

  Power supply comprising a vacuum vessel equipped with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device And a substrate holding means for disposing a substrate to be plasma-processed, and processing the surface of the substrate using the generated plasma. A plasma surface treatment apparatus comprising a converter.   Power supply comprising a vacuum vessel equipped with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device And a substrate holding means for disposing a substrate to be plasma-processed, and a plasma surface processing apparatus for processing the surface of the substrate using the generated plasma. A high-frequency power source, an impedance matching device, a transformer-type balanced / unbalanced converter, and a current introduction terminal having two ungrounded conductors as power lines are arranged in this order from upstream to downstream. Plasma surface treatment equipment.   Power supply comprising a vacuum vessel equipped with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device And a substrate holding means for arranging a substrate to be plasma-processed, and a plasma surface treatment apparatus for treating the surface of the substrate by using the generated plasma. A plasma surface treatment apparatus comprising a transformer-type balun using a cable.   A vacuum vessel provided with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a power supply system comprising a high-frequency power source and an impedance matching device, and plasma treatment And a substrate holding means for disposing a substrate to be processed, and a plasma surface processing apparatus for processing the surface of the substrate using the generated plasma. A plasma surface treatment apparatus comprising a converter.   Power supply comprising a vacuum vessel equipped with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device And a substrate holding means for arranging a substrate to be plasma-treated, and a plasma surface treatment apparatus for treating the surface of the substrate using the generated plasma. A plasma surface treatment apparatus comprising: a core, and a transformer type unbalanced converter in which a plurality of coaxial cables are used for windings wound around the toroidal core and connected in parallel.   Power supply comprising a vacuum vessel equipped with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device And a substrate holding means for arranging a substrate to be plasma-treated, and a plasma surface treatment apparatus for treating the surface of the substrate using the generated plasma. A plasma surface treatment apparatus comprising: a plurality of transformer-type balanced / unbalanced converters each including a core and a coaxial cable, and the plurality of transformer-type balanced / unbalanced converters connected in parallel.   The plasma surface treatment apparatus according to any one of claims 1 to 4, wherein a direction of a winding start part of a winding and a direction of a line of a winding end part of the component of the transformer type balun The plasma surface treatment apparatus has a structure in which the two are substantially orthogonal to each other.   The plasma surface treatment apparatus according to any one of claims 5 and 6, wherein the direction of the core wire of the coaxial cable and the direction of the core wire of the winding end portion of the component of the transformer type balun The plasma surface treatment apparatus has a structure in which the two are substantially orthogonal to each other.   The plasma surface treatment apparatus according to any one of claims 1 to 8, wherein a temperature control device is provided in which a temperature of the transformer-type balanced / unbalanced converter is set to an arbitrary value within a range of 50 ° C to 150 ° C. A plasma surface treatment apparatus.   The plasma surface treatment apparatus according to any one of claims 1 to 9, wherein the transformer-type balanced / unbalanced converter is disposed inside the vacuum vessel.   Power supply comprising a vacuum vessel equipped with an exhaust system, a discharge gas supply system for supplying a discharge gas into the vacuum vessel, an electrode for generating plasma, a high-frequency power source, an impedance matching device, and a balance-unbalance conversion device And a substrate holding means for disposing a substrate to be plasma-processed, and a plasma surface processing apparatus for processing the surface of the substrate using the generated plasma. A plasma surface treatment apparatus comprising: a high-frequency power source, a balanced impedance matching device, a transformer-type balanced / unbalanced converter, and a balanced current introduction terminal arranged in this order from the upstream side to the downstream side.

Images