JP2006100551A - Plasma deposition method, plasma processing device, solar cell and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma deposition method which enables improvement of film quality and uniformity of film quality, and also can correspond to enlargement of an area of a substrate. <P>SOLUTION: In the plasma deposition method, a thin film of raw gas is generated on a substrate 3 by plasma chemical deposition. High frequency electric field is applied by introducing hydrogen gas into vacuum, and hydrogen radical is generated wherein hydrogen gas is excited to a plasma state. A film is manufactured on the substrate 3 by supplying raw gas from a system different from the hydrogen gas, and the raw gas and the hydrogen radical are made to react with each other in a space which is free from plasma. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma film forming method in which various plasma processes such as etching, sputtering, or CVD (chemical vapor deposition) are performed on a substrate to be processed using plasma.

Conventionally, thin film formation and etching in semiconductors and electronic parts are often performed using plasma. Particularly, in the formation of thin films such as amorphous and microcrystalline solar cells and thin film transistors (TFT liquid crystals), typical examples of plasma treatment A plasma CVD apparatus using the CVD method is used.
Plasma CVD is a method in which energy such as electromagnetic waves is applied to a specific substance and discharged to make the specific substance a chemically active radical, and this radical is brought into contact with the substrate to be processed. A method of forming a thin film on top.

In the above-described conventional plasma processing, one kind of gas (mixed gas of raw material gas and hydrogen gas) is supplied from one gas supply system, and a thin film is formed at one plasma generation region.
On the other hand, in recent plasma treatments, for example, in order to increase the productivity by increasing the area of a solar cell, a film formation process for uniformly forming a film on a large-area substrate is required. From such a background, a thin film forming apparatus and a high frequency plasma CVD apparatus that provide a method for forming a semiconductor thin film that can prevent damage caused by ions and that can be easily formed uniformly over a large area have been proposed. In this prior art, each of a plurality of strip-like cathode portions and anode portions on the substrate has electrodes having a configuration in which the plasma forming regions are alternately arranged. In this prior art, one kind of gas is supplied and plasma is generated at one place between the anode part and the cathode part. (For example, see Patent Document 1)
Japanese Patent Laid-Open No. 2001-26878

  As described above, in recent plasma processing, it is required to improve the film-forming film quality and increase the area of the substrate. However, in the prior art in which one kind of gas is supplied and plasma is generated at one place, film quality control (adjustment of radical supply method, adjustment, etc.) is greatly restricted. It was difficult to form a quality thin film uniformly. Therefore, it is desired to develop a plasma processing technique that can improve the film quality, make the film quality uniform, and can cope with an increase in the area of the substrate.

The present invention has been made in view of the above circumstances, and the object of the present invention is to improve the film quality, to make the film quality uniform, and to support the increase in the area of the substrate. It is to provide a method.
Another object of the present invention is to provide a plasma processing apparatus, a solar cell, and a solar cell manufacturing method to which the above-described plasma film forming method is applied.

In order to solve the above problems, the present invention employs the following means.
The plasma film forming method according to claim 1 is a plasma film forming method for generating a thin film of a source gas on a substrate by plasma chemical vapor deposition,
Hydrogen gas is introduced into a vacuum and a high frequency electric field is applied to generate hydrogen radicals excited in a plasma state, and the source gas is supplied from a system separate from the hydrogen gas. And the hydrogen radicals are reacted in a plasma-free space to form a film on the substrate.

According to such a plasma film forming method, hydrogen gas is introduced into a vacuum and a high-frequency electric field is applied to generate abundantly generated hydrogen radicals that are excited to a plasma state, and the source gas is made into hydrogen gas. Is supplied from a separate system, and the source gas and abundant hydrogen radicals are reacted in a plasma-free space to form a film on the substrate, so there is no plasma in the film-forming region, contributing to film quality deterioration. Generation of radicals (for example, SiH ₂ radicals) can be suppressed, and radicals (for example, SiH ₃ radicals) that are effective for improving the quality of film formation can be efficiently generated.

In the plasma film-forming method according to claim 1, if the source gas is silane gas (SiH ₄ ), a high-quality Si thin film can be generated on the substrate.
Moreover, in the plasma film-forming method according to claim 1 or 2, by using the substrate heated to 500 ° C to 700 ° C, for example, a thermal CVD method for forming a film on a heat-resistant metal substrate, The combination with hydrogen radical supply enables high-quality film formation on a metal substrate.

A plasma film forming method according to claim 4 is a plasma film forming method for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition,
A first source gas diluted with hydrogen is introduced into a vacuum, a high-frequency electric field is applied to generate a plasma of the first source gas, and a second source gas diluted with hydrogen in a vacuum And a second plasma generation region for generating a plasma of the second source gas by applying a high-frequency electric field, and crystal grains of the first source gas generated in the first plasma generation region are provided. The second plasma generation region is supplied to form an amorphous film.

  According to such a plasma film forming method, a first plasma generation region for generating a plasma of the first source gas by introducing a first source gas diluted with hydrogen into a vacuum and applying a high-frequency electric field; A second source gas diluted with hydrogen is introduced into a vacuum, a high-frequency electric field is applied, and a second plasma generation region for generating plasma of the second source gas is provided, and is generated in the first plasma generation region Since the first raw material gas crystal grains are supplied to the second plasma generation region to form an amorphous film, high quality film formation with a low deterioration rate is possible.

  In the plasma film-forming method according to claim 4, it is preferable that the second plasma generation region is turned on and the first plasma generation region is alternately controlled to be turned on and off. A multilayer film can be formed by alternately forming layers and amorphous film-forming layers including crystal grains.

  6. The plasma film forming method according to claim 4, wherein the high-frequency electric field preferably has a higher frequency on the first plasma generation region side than the second plasma generation region. The crystal grains of the source gas can be generated with high efficiency.

7. The plasma film forming method according to claim 4, wherein if the first source gas and the second source gas are silane gas (SiH ₄ ), a high-quality Si thin film can be formed on the substrate. it can.
Further, in the plasma film forming method according to any one of claims 4 to 6, if the first source gas is GeH ₄ and the second source gas is SiH ₄ , plasma condition adjustment (frequency, ON) / OFF), an amorphous film-forming layer or a microcrystalline film-forming layer of silicon and germanium can be alternately formed to be multilayered.

A plasma film forming method according to claim 9 is a plasma film forming method for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition,
A high frequency electric field is applied by introducing hydrogen gas into a vacuum, and a high frequency electric field is applied by introducing a mixed gas of hydrogen gas and source gas into the first plasma generation region for generating the hydrogen gas plasma. And a second plasma generation region that generates plasma of the mixed gas, ON / OFF control of the first plasma generation region, and hydrogen radicals generated in the first plasma control region The film is formed by intermittently supplying to the plasma generation region 2.

  According to such a plasma film forming method, hydrogen gas is introduced into a vacuum and a high-frequency electric field is applied to generate a plasma of the hydrogen gas, and a hydrogen gas and a source gas in the vacuum are generated. A mixed gas is introduced, a high-frequency electric field is applied, and a second plasma generation region for generating a plasma of the mixed gas is provided, and the first plasma generation region is ON / OFF controlled and generated in the first plasma control region Since the hydrogen radicals are intermittently supplied to the second plasma generation region for film formation, high quality film formation can be performed by intermittently supplying hydrogen radicals in combination during film formation.

A plasma film forming method according to claim 10 is a plasma film forming method for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition,
A high-frequency electric field is applied by introducing a mixed gas of hydrogen gas and source gas into a vacuum, and a high-frequency electric field is generated by introducing argon (Ar) gas into the vacuum. A second plasma generation region for generating an argon gas plasma is provided by applying an electric field, and the film formation using the raw material gas and the argon ion treatment are combined to form a film.

  According to such a plasma film forming method, a first plasma generation region in which a mixed gas of hydrogen gas and a raw material gas is introduced into a vacuum and a high frequency electric field is applied to generate a plasma of the mixed gas; Argon (Ar) gas is introduced, a high-frequency electric field is applied, a second plasma generation region for generating argon gas plasma is provided, and film formation using raw material gas and argon ion treatment are combined to form a film. It is possible to control the hydrogen concentration on the outermost surface of the film, which influences the film quality, and the band cap control.

  The plasma processing apparatus according to claim 11 is provided with a plasma film forming means for forming a film by the plasma film forming method according to any one of claims 1 to 10 in a chamber provided with an adjustable internal pressure. It is characterized by being.

  According to such a plasma processing apparatus, since the plasma film forming means for forming the film by the plasma film forming method according to any one of claims 1 to 10 is provided, high quality film formation is performed on the substrate. Can do.

The plasma processing apparatus according to claim 12, wherein a plasma film forming means is provided in a chamber capable of adjusting an internal pressure, and a thin film of a source gas is formed on a substrate by plasma chemical vapor deposition,
The plasma film forming means is opposed to each other at a predetermined interval and extends and crosses the width direction of the substrate, and an insulator for insulating and covering the positive electrode and the negative electrode so as not to contact each other And a hydrogen gas flow path and a source gas flow path independently formed inside the insulator, and a plurality of feeding points are provided on the positive electrode and the negative electrode, and the positive electrode and the negative electrode A high-frequency electric field is applied to the hydrogen gas introduced therebetween to generate hydrogen radicals in which the hydrogen gas is excited into a plasma state, and the source gas and the hydrogen radicals are reacted in a plasma-free space on the substrate. It is characterized by being formed into a film.

  According to such a plasma processing apparatus, the plasma film forming means is opposed to each other with the positive electrode and the negative electrode facing each other at a predetermined interval and extending across the width direction of the substrate. An insulating material to be insulated and coated, and a hydrogen gas flow channel and a raw material gas flow channel independently formed inside the insulating material, a plurality of feeding points are provided on the positive electrode and the negative electrode, and A high-frequency electric field is applied to the hydrogen gas introduced between the positive electrode and the negative electrode to generate hydrogen radicals excited in a plasma state, and the source gas and hydrogen radicals are reacted in a space without plasma to react on the substrate. Therefore, even if the electrode is lengthened, it is not necessary to consider the influence of the wavelength due to the high-frequency power source, and therefore, the cost for film formation on a large area substrate can be reduced by mass production. .

  13. The plasma processing apparatus according to claim 12, wherein the position of the insulator is preferably variable together with the positive electrode and the negative electrode, thereby adjusting the plasma generation region to adjust the film forming speed and film quality. It becomes possible.

The plasma processing apparatus according to claim 14, wherein a plasma film forming means is provided in a chamber capable of adjusting an internal pressure, and a thin film of a source gas is formed on a substrate by plasma chemical vapor deposition,
The plasma film forming means includes a hollow box-shaped positive electrode in which a hydrogen gas flow path for introducing hydrogen gas into the internal space is formed, and a hollow box in which a plasma generation region is formed in the internal space and the positive electrode is accommodated A negative gas electrode and a source gas channel formed outside the negative electrode, and a high frequency electric field is applied to the hydrogen gas introduced into the positive electrode to excite the hydrogen gas into a plasma state. The hydrogen radical is generated, and the source gas and the hydrogen radical are reacted in a plasma-free space outside the positive electrode to form a film on the substrate.

  According to such a plasma processing apparatus, the plasma film forming means forms a hollow box-shaped positive electrode in which a hydrogen gas flow path for introducing hydrogen gas into the internal space is formed, and a plasma generation region in the internal space. A hollow box-shaped negative electrode that houses and installs a positive electrode, and a raw material gas channel formed outside the negative electrode, and a high-frequency electric field is applied to the hydrogen gas introduced into the positive electrode to generate hydrogen plasma. Since hydrogen radicals excited to a state are generated and the source gas and hydrogen radicals are reacted in a space without plasma outside the positive electrode to form a film on the substrate, the film is formed in a space separate from the film forming part. Thus, a uniform plasma of hydrogen gas can be formed, and hydrogen radicals can be supplied to the substrate to form a film. For this reason, since the radicals of the source gas effective for improving the film quality can be selectively generated to form a film, a high-quality film can be formed.

The plasma processing apparatus according to claim 15, wherein a plasma film forming means is provided in a chamber capable of adjusting an internal pressure, and a thin film of a source gas is formed on a substrate by plasma chemical vapor deposition,
The plasma film forming means forms a hollow box-shaped positive electrode in which a hydrogen gas flow path for introducing hydrogen gas into the internal space is formed, and forms a first plasma generation region in the internal space and accommodates the positive electrode. A hollow box-shaped negative electrode, a source gas flow path formed outside the negative electrode, and a positive electrode member disposed between the negative electrode and the substrate to allow gas flow. Equipped,
The first plasma generation region in the positive electrode and the second plasma formation region formed around the positive electrode member are each subjected to independent plasma generation ON / OFF control to form a film on the substrate. It is characterized by comprising.

  According to such a plasma processing apparatus, the plasma film forming means includes a hollow box-shaped positive electrode in which a hydrogen gas flow path for introducing hydrogen gas into the internal space is formed, and the first plasma generation region in the internal space. A hollow box-shaped negative electrode that is formed and accommodates a positive electrode, a raw material gas channel formed outside the negative electrode, and disposed between the negative electrode and the substrate to enable gas flow. A positive electrode member, and a first plasma generation region in the positive electrode and a second plasma formation region formed around the positive electrode member perform independent ON / OFF control of plasma generation on the substrate. Therefore, independent plasma generation can be performed in the two plasma generation regions, and high-quality film formation is possible.

The plasma processing apparatus according to claim 16, wherein a plasma film forming means is provided in a chamber capable of adjusting an internal pressure to form a thin film of a source gas on a substrate by plasma chemical vapor deposition,
The plasma film forming means forms a hollow box-shaped negative electrode in which a hydrogen gas flow path for introducing hydrogen gas into the internal space is formed, and forms a first plasma generation region in the internal space and accommodates the negative electrode. A hollow box-shaped positive electrode, and a source gas flow path formed outside the positive electrode, and a second plasma generation region is formed between the positive electrode and the substrate to A plasma film forming means configured to form a film is provided.

  According to such a plasma processing apparatus, the plasma film forming means includes a hollow box-shaped negative electrode in which a hydrogen gas flow path for introducing hydrogen gas into the internal space is formed, and the first plasma generation region in the internal space. A hollow box-shaped positive electrode that is formed and accommodates a negative electrode, and a source gas channel formed outside the positive electrode, and a second plasma generation region is formed between the positive electrode and the substrate Since the film is formed on the substrate, plasma can be generated in two regions at the same time by one set of high-frequency power supplies (two units), which can reduce the power supply cost and simplify the structure. become.

17. The plasma processing apparatus according to claim 16, wherein the feed system connected to the positive electrode and the negative electrode is preferably phase-controlled by a variable stub circuit, thereby changing the position of the standing wave in the longitudinal direction. Thus, the film quality can be made uniform.
Further, in the plasma processing apparatus according to any one of claims 12 to 17, it is preferable to include a transfer / moving unit that relatively moves the plasma film forming unit and the substrate during film formation. Film formation corresponding to the increase in area of the substrate can be performed.
In the plasma processing apparatus according to any one of claims 12 to 18, it is preferable that a plurality of the plasma film forming means are electrically connected in parallel, whereby a large area of the substrate is obtained. Film formation corresponding to the conversion can be performed.
In the plasma processing apparatus according to any one of claims 12 to 19, it is preferable that a bias is applied to the negative electrode side, whereby film quality control such as a film forming speed can be controlled by adjusting a plasma density. It becomes possible.

  Since the solar cell of Claim 21 is equipped with the thin film formed by the plasma processing apparatus in any one of Claim 11 to 20, it becomes possible to form a high quality thin film, and also the large-sized solar cell. Can be realized.

  Since the method for manufacturing a solar cell according to claim 22 uses the plasma processing apparatus according to any of claims 11 to 20, it is easy to form a high-quality thin film, and a large-sized and high-quality thin film is formed. The provided solar cell can be easily manufactured.

As described above, the plasma processing apparatus of the present invention is suitable for forming a thin film constituting a solar cell.
Examples of the solar cell include a solar cell having at least one pin structure or nip structure polycrystalline silicon layer composed of a p-type silicon layer, an n-type silicon layer, and an i-type silicon layer, a p-type silicon layer, and an n-type silicon. A solar cell having at least one pin structure or nip structure amorphous silicon layer comprising a layer and an i-type silicon layer, a pin structure or nip structure polycrystalline silicon layer, and a pin structure or nip structure amorphous silicon layer A so-called tandem solar cell having a two-layer structure, an amorphous silicon layer having a pin structure or a nip structure, a polycrystalline silicon layer having a pin structure or a nip structure, and another polycrystalline silicon layer having a pin structure or a nip structure. A so-called triple solar cell having a three-layer structure can be given.

  According to the present invention described above, it becomes possible to easily and uniformly form a high-quality thin film on a substrate by using plasma treatment, and in particular, improve the quality of a film-forming product having a large area such as a solar cell. And has a remarkable effect on productivity.

Hereinafter, as an embodiment of a plasma processing apparatus using the plasma processing method according to the present invention, a plasma CVD apparatus will be described with reference to the drawings.
FIG. 5 is a schematic diagram showing a configuration of a plasma CVD apparatus according to an embodiment of the present invention. As shown in FIG. 5, the plasma CVD apparatus 1 according to this embodiment includes a chamber 2 that can be vacuum-processed. A plasma generation source 10 that generates plasma in the chamber 2 is disposed in the chamber 2. The plasma generation source 10 is provided so that the longitudinal direction is orthogonal to the transport direction of the substrate 3 (arrow 4 in the figure) in order to cope with, for example, an increase in the area of the substrate 3.

  Below the substrate 3, a roller 5 is provided as a transporting / moving means for transporting the substrate 3 in a state of facing the plasma generation source 10. The roller 5 conveys the substrate 3 in a predetermined direction at a predetermined speed. The substrate 3 is disposed on the substrate carrier 6, heated to a predetermined temperature by a heater (not shown) installed below the roller 5, and moves on the roller 5 together with the substrate carrier 6. Further, since the plasma generation source 10 shown in FIG. 5 is electrically connected in parallel at a predetermined interval in the transport direction, for example, three rows (three sets) are provided, so that the area of the substrate 3 can be increased. It becomes effective. The transport / moving means and the parallel connection described above are effective means corresponding to an increase in the area of the substrate 3 by adopting at least any one of the embodiments described later.

<First Embodiment>
Here, as an example of plasma film forming means using the plasma processing method according to the present invention, a first embodiment of a plasma generation source 10 will be described with reference to FIGS.
First, a plasma film forming method for generating a raw material gas thin film on a substrate 3 by plasma chemical vapor deposition will be described with reference to FIG. In this plasma film forming method, hydrogen gas is introduced into the vacuum in the chamber 2 and a high frequency electric field is applied, and the hydrogen gas generates hydrogen radicals excited in a plasma state. Along with this supply of hydrogen gas, the raw material gas is supplied through a flow path separate from the hydrogen gas. In the following description, silane gas (SiH ₄ ) is used as a source gas in order to form a silicon (Si) thin film on the surface of the substrate 3. In this case, it is assumed that the source gas in this case is silane gas alone and supplied through a dedicated supply system provided independently.

In FIG. 1 (a), a pair of positive electrode 11 and negative electrode 12 are arranged opposite to each other with a predetermined interval W in the transport direction indicated by an arrow 4 in the figure as electrodes for applying a high-frequency electric field to hydrogen gas. Yes. The positive electrode 11 and the negative electrode 12 have a flat plate shape, and are insulated and covered with an insulator 15 having a hydrogen gas flow path 13 and a source gas flow path 14 so that they do not come into contact with each other except for the tip on the substrate 3 side. Yes. For the insulator 15, a ceramic insulating material such as alumina is used.
Hydrogen gas and silane gas pass through the hydrogen gas flow path 13 and the source gas flow path 14, respectively, and are introduced to a space near the plasma generation region P where the hydrogen gas is excited into a plasma state and generates hydrogen radicals. The hydrogen gas passage 13 and the source gas passage 14 are provided with gas outlets 13 a and 14 a that open to the surface of the insulator 15 that faces the substrate 3, respectively.

One positive electrode 11 is connected to a high-frequency power supply (not shown) via an electric wire 17 passing through the power supply path 16. The other negative electrode 17 is connected to the power supply path 16 and is grounded at an appropriate position of the power supply path 16. A high-frequency power source is applied between the electrodes 11 and 12 thus configured, hydrogen gas is allowed to flow through the hydrogen gas channel 13, and silane gas is allowed to flow into the source gas channel 14 to start film formation.
Then, a high frequency electric field is formed between the electrodes 11 and 12, and hydrogen gas supplied to the high frequency electric field from the gas outlet 13a is excited into a plasma state by the energy of the high frequency electric field. As a result, abundant hydrogen radicals are generated, and a silicon thin film can be formed on the substrate 3 by reacting the hydrogen radicals with the silane gas supplied from the gas outlet 14a in a plasma-free space. . That is, the gas outlet 14a for the silane gas is provided so as to eject the silane gas into a space region adjacent to the vicinity of the region where the hydrogen gas becomes plasma so as not to react directly with the hydrogen gas plasma.

As described above, abundantly generated hydrogen radicals are reacted with silane gas in a plasma-free space to selectively produce SiH ₃ that is considered good for film quality by the reaction shown in the following chemical formula. can do.
SiH ₄ + H → SiH ₃ + H ₂
In other words, hydrogen gas and silane gas are supplied in separate systems, and only hydrogen gas is excited into a plasma state to generate abundant hydrogen radicals, so the reaction of the above chemical formula is promoted by the presence of abundant hydrogen radicals. The Accordingly, the generation of SiH ₂ radical, which is generated by the influence of plasma on the silane gas and contributes to the deterioration of the film quality and is undesirable for the formation of a good film quality, can be suppressed, thereby contributing to the formation of a high-quality thin film. SiH ₃ radicals can be generated efficiently.

Further, in FIG. 1A described above, the pair of electrodes 11 and 12 are disposed to face each other in the transport direction. However, as in the modification shown in FIG. 1B, for example, one positive electrode 11 is provided at the center. May be provided, and a plasma generation source 10 ′ having a configuration in which two negative electrodes 12 are opposed to each other with a predetermined interval W on each of the left and right sides thereof may be used.
In this modification, the three electrodes 11, 12 arranged in the transport direction indicated by the arrow 4 in the figure are covered with an insulator 15 ′ having a hydrogen gas channel 13 and a source gas channel 14. In this case, the hydrogen channel 13 is arranged on both sides of the positive electrode 11, and the source gas channel 14 is arranged outside the negative electrode 12. That is, the negative electrode 12, the hydrogen gas flow path 13 and the source gas flow path 14 are symmetrically arranged with the positive electrode 11 as the center, and the left and right space portions adjacent to the hydrogen gas plasma generation region P formed in the center portion. The silane gas is supplied from the gas outlet 14a.

  Even in such a configuration, a high-frequency electric field is formed between the positive electrode 11 and the negative electrode 12 disposed on both sides, and hydrogen gas supplied to the high-frequency electric field from the two gas outlets 13a is excited into a plasma state. Therefore, abundant hydrogen radicals are generated. Then, by reacting this hydrogen radical with silane gas supplied from the gas outlet 14a in a plasma-free space, a high-quality silicon thin film can be formed on the substrate 3 as in the above-described embodiment. . As described above, the configuration in which the three electrodes are arranged in the transport direction has an advantage that the electrode symmetry / polarity is symmetric with respect to the substrate transport direction, so that the plasma symmetry / stability is improved.

By the way, the insulators 15 and 15 ′ described above are integrated with the electrodes 11 and 12, and their positions are made variable in the vertical direction (arrow 18 in the drawing), so that the plasma processing surface and the plasma generation region of the substrate 3 are changed. The distance from P can be adjusted as appropriate. By adjusting the plasma generation region P as described above, a desired film forming speed can be set.
That is, by bringing the plasma generation region P closer to the substrate 3, it is possible to increase the film forming speed and improve the productivity. Further, by moving the plasma generation region P away from the substrate 3, the film forming speed is slowed, which is disadvantageous in terms of productivity, but the film quality is improved by reducing the damage that the film forming receives from the plasma. Therefore, the optimum distance can be adjusted in consideration of the correlation between productivity and film quality.

FIG. 2 shows an application example to a plasma CVD apparatus that employs the above-described plasma generation source 10 ′ and forms a film on the substrate 3 having a large area. In this case, the substrate 3 has a substrate width orthogonal to the conveyance direction indicated by the arrow 4 and is about 2 to 3 m, which is significantly larger than the conventional 1 m class.
In order to uniformly form the film thickness on such a substrate 3, a plurality of feeding points are provided at equal pitches in the substrate width direction with respect to the positive electrode 11 and the negative electrode 12 which are elongated according to the substrate width. is there. That is, a plurality of power supply paths are provided in the longitudinal direction of the positive electrode 11 and the negative electrode 12, and a plurality (eight positions in the illustrated example) of power supply points are provided connected to a plurality of positions of each electrode. Note that a high-frequency voltage having a frequency f is applied to the electric wire 17 connected to the positive electrode 11 from the high-frequency power source 19 via the matching unit 20, and the power supply path 16 connected to the negative electrode 12 is grounded.

By adopting such a power supply structure, in the longitudinal direction L of the positive electrode 11 and the negative electrode 12, even if L is increased for the purpose of increasing the area of the substrate 3, there is almost no phase difference between the respective power supply points. Therefore, as shown in FIG. 3, the voltage V becomes substantially uniform. Therefore, since plasma can be generated substantially uniformly in the substrate width direction of the substrate 3, the film quality in this direction can also be made uniform. Further, since the film is formed by moving the substrate 3 in the conveyance direction, the film quality can be uniform in the conveyance direction, and uniform and high-quality film formation can be performed on the entire substrate 3 having a large area. .
In addition, about the longitudinal direction L of the positive electrode 11 and the negative electrode 12, it is good also as a structure which divides | segments into plurality and covers the whole.

In the application example of FIG. 2 described above, the power supply path 16 electrically connected to the negative electrode 12 is simply grounded. However, as shown in FIG. 4, for example, a bias such as a DC power supply or a low-frequency power supply is applied. The film quality may be controlled by increasing the plasma density on the substrate 3 side. In other words, the deposition rate can be controlled by adjusting the plasma density.
In the configuration example of FIG. 4A, the power supply path 16 connected to the negative electrode 12 is grounded via the coupling capacitor 21 and the low frequency power supply 22. In the configuration example of FIG. 4B, the power supply path 16 connected to the negative electrode 12 is grounded via a resistor 23 and a DC power supply 24. In general, the polarity of the power supply is generally set to be negative in order to reduce + ion damage to the substrate 3, and therefore, a negative voltage is applied through a resistor, but this is not restrictive.

In the plasma CVD apparatus 1 described above, self-cleaning in the chamber 2 for removing the silicon film is possible. Hereinafter, cleaning using NF ₃ plasma will be described as a representative example of self-cleaning.
In this self-cleaning, NF ₃ gas is supplied into the chamber 2 to generate plasma, whereby the following reaction occurs and self-cleaning is performed.
2NF ₃ + e → N ₂ + 6F + e (e: electron in plasma)
Si + 4F → SiF ₄
That is, F radicals are generated in the upper reaction equation, and Si in the chamber 2 is automatically removed as SiF ₄ gas in the lower reaction equation, so that productivity can be improved by increasing the operating rate. it can.

<Second Embodiment>
Next, a second embodiment of the plasma generation source, which is a plasma film forming means using the plasma processing method according to the present invention, will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part similar to 1st Embodiment mentioned above, and the detailed description is abbreviate | omitted.
First, a plasma film forming method employed by the plasma generation source 10A of the present embodiment will be described with reference to FIG. In this plasma film forming method, as in the first embodiment described above, hydrogen gas is introduced into the vacuum in the chamber 2 and a high frequency electric field is applied, and hydrogen radicals excited by the hydrogen gas into a plasma state are removed. Generate. Along with this hydrogen gas supply, silane gas is supplied as a raw material gas through a flow path different from the hydrogen gas. In this case, the source gas is supplied by a silane gas alone through a dedicated supply system provided independently.

In order to realize the plasma film forming method described above, the plasma generation source 10A of the present embodiment forms a hollow box-shaped positive electrode 31 in which the internal space forms the hydrogen gas flow path 30 and a plasma generation region P in the internal space. The negative electrode 32 having a hollow box shape and a source gas channel 33 formed outside the negative electrode 32 are provided, and the positive electrode 31 is housed and installed in the internal space of the negative electrode 32.
The positive electrode 31 has a rectangular parallelepiped shape, and a gas outlet 31 a for releasing hydrogen gas introduced through the hydrogen gas flow path 30 is provided on the lower surface thereof.

The negative electrode 32 has a rectangular parallelepiped shape that surrounds the outer side of the positive electrode 31 and forms the plasma generation region P, and is arranged such that its lower surface faces the film forming surface of the substrate 3 with a predetermined interval. In addition, a hydrogen radical outlet opening 32a, which will be described later, is provided on the lower surface of the negative electrode 32 facing the substrate 3.
A pair of source gas flow paths 33 are provided on the outside of the negative electrode 32 so as to sandwich the outlet opening 32a. When the substrate 3 is transported and plasma processing is performed, the source gas flow path 33 is arranged before and after the transport direction (arrow 4 in the figure) so as to sandwich the outlet opening 32a.

One positive electrode 31 is connected to a high-frequency power supply (not shown), and the other negative electrode 32 is grounded. A high frequency power source is applied between the electrodes 31 and 32 configured in this manner, hydrogen gas is allowed to flow through the hydrogen gas flow path 30, and silane gas is allowed to flow into the source gas flow path 33 to start film formation.
Then, a high frequency electric field is formed between the electrodes 31 and 32, and hydrogen gas supplied from the gas outlet 31a to the high frequency electric field is excited into a plasma state by the energy of the high frequency electric field. As a result, abundant hydrogen radicals are generated in the plasma generation region P, so that the hydrogen radicals flow out from the outlet opening 32a and react with the silane gas supplied from the gas outlet 33a in the upper space of the substrate 3 without plasma. Thus, a silicon thin film can be formed on the substrate 3. That is, the gas outlet 33a of the silane gas is supplied so as to be ejected to the outside of the negative electrode 32 that defines the plasma generation region P so as not to react directly with the hydrogen gas plasma.

As described above, abundantly generated hydrogen radicals, and by reacting the hydrogen radicals with silane gas in a plasma-free space, SiH, which is good for film quality, is obtained by the same reaction formula as in the first embodiment. ₃ can be selectively generated.
That is, hydrogen gas and silane gas are supplied by different systems, and only hydrogen gas is excited into a uniform plasma state in the internal space of the negative electrode 32 to generate abundant hydrogen radicals. The presence of the reaction promotes the reaction described above. Therefore, since the silane gas is not affected by the plasma, it contributes to deterioration of the film quality, suppresses the generation of SiH ₂ radicals that are undesirable for the formation of a good film quality, and efficiently converts the SiH ₃ radicals that contribute to the formation of a high-quality thin film. It is possible to generate well.

7 and 8 are schematic configuration diagrams showing an application example to a plasma CVD apparatus that employs the above-described plasma generation source 10A and forms a film on the substrate 3 having a large area.
In this application example, both ends of the positive electrode 31 are connected to the first high-frequency power source 34 and the second high-frequency power source 35, respectively, and the negative electrode 32 is grounded at two locations.
In the plasma generation source 10A configured as described above, by applying the phase modulation method to the power feeding method, the substrate width (dimension in the position L direction in FIG. 8) is high with respect to a large substrate 3 having a size of 2 to 3 m. Quality film formation is possible, and high-quality film formation corresponding to an increase in the area of the substrate 3 can be performed.

Specifically, when high-speed phase modulation (about several tens KHz) is performed, the position L to which the maximum voltage V is applied moves at high speed in the substrate width direction, so that it is uniform in the plasma generation space of the plasma generation region P. Therefore, a uniform film can be formed on the film forming surface of the substrate 3.
Further, by performing low-speed phase modulation (for example, 1 Hz or less), the position L to which the maximum voltage V is applied moves at a low speed in the substrate width direction, so that plasma generation in the plasma generation space of the plasma generation region P is performed. Can be turned ON / OFF continuously. For this reason, the standing wave can move and the plasma generation region P can be swung, and if a fixed point observation is performed at a certain place, the state of plasma generation is the same as the ON / OFF state of the plasma. A uniform film can be formed on the film surface.

If the plasma generation source 10A described above forms a film while conveying and moving the substrate 3 in a direction perpendicular to the positive electrode 31 and the negative electrode 32, the area of the substrate 3 that can be formed is indicated by an arrow 4 in the figure. It can be easily expanded in the transport direction shown.
Moreover, by connecting in parallel the electrode unit comprising the above-described positive electrode 31 and negative electrode 32, that is, by arranging a plurality in parallel in the transport direction described above, the substrate 3 can be manufactured without moving. The film area can be increased to increase the area. In addition, the combination with such parallel arrangement of the electrode units and the movement of the substrate 3 described above makes it easier to cope with the increase in area.

Further, in the application example of FIG. 7 described above, the negative electrode 32 is simply grounded. However, as in the first embodiment (see FIG. 4), a bias such as a DC power source or a low frequency power source is applied. Then, film formation control for increasing the plasma density on the substrate 3 side may be performed.
Also in this embodiment, self-cleaning in the chamber 2 for removing the silicon film is possible as in the first embodiment described above.

  In the second embodiment described above, high-quality film formation is possible by a combination of a thermal CVD method in which the substrate 3 is heated to 500 ° C. to 700 ° C. and hydrogen radical supply. That is, by generating hydrogen radicals in the plasma region P and supplying hydrogen radicals to the thermal CVD film forming region on a substrate 3 made of metal or the like that can withstand high temperatures, surface treatment (hydrogen of the hydrogen radicals in the film forming) (Drawing reaction) is performed, so that the quality of the film can be improved.

<Third Embodiment>
Next, a third embodiment will be described with reference to FIG. 9 for a plasma generation source which is a plasma film forming means using the plasma processing method according to the present invention. In addition, the same code | symbol is attached | subjected to the part similar to each embodiment mentioned above, and the detailed description is abbreviate | omitted.
The plasma film forming method of this embodiment is different in that two plasma generation regions P1 and P2 are formed. That is, a first source gas (high hydrogen diluted source gas) diluted with hydrogen (gas) is introduced into a vacuum in the chamber 2 and a high frequency electric field is applied to generate a plasma of the high hydrogen diluted source gas. A second source gas (low hydrogen diluted source gas) diluted with hydrogen (gas) is introduced into the plasma generation region P1 and the vacuum in the chamber 2, and a high frequency electric field is applied to generate plasma of the low hydrogen diluted source gas. The second plasma generation region P2 is provided, and the crystal grains of the first source gas generated in the first plasma generation region P1 are supplied to the second plasma generation region P2 to form an amorphous film.

  In order to realize the plasma film forming method described above, the plasma generation source 10B of this embodiment includes a hollow box-shaped negative electrode 31 'in which the internal space forms a high hydrogen dilution source gas flow path 30', and a plasma in the internal space. It is formed between the hollow box-shaped positive electrode 32 'forming the generation region P1, the low hydrogen dilution source gas flow path 33' formed outside the positive electrode 32 ', and the substrate 3 and the positive electrode 32'. In order to form a plasma generation region P2, a ground 34 provided on the substrate carrier 6 is provided, and a negative electrode 31 'is housed and installed in the internal space of the positive electrode 32'. That is, as compared with the second embodiment shown in FIG. 6, the ground 34 is provided by reversing the polarity of the electrodes 31 'and 32', and the gas used for the plasma processing is different. Yes.

Here, the high hydrogen dilution source gas and the low hydrogen dilution source gas will be described. The high hydrogen diluted raw material gas (hereinafter referred to as “highly diluted mixed gas”) is a mixed gas of silane gas (first raw material gas) and hydrogen gas. For example, the mixing ratio of silane gas and hydrogen gas is about 1:50. As a result, the ratio of hydrogen gas is set very high. The low hydrogen diluted source gas (hereinafter referred to as “low diluted mixed gas”) is also a mixed gas of silane gas (second source gas) and hydrogen gas. For example, the mixing ratio of silane gas and hydrogen gas is 1 : The ratio of hydrogen gas is set to be a little higher than about 5.
A high-frequency power source is applied between the electrodes 31 ′ and 32 ′ and the positive electrode 32 ′ / substrate 3 configured as described above, and a highly diluted mixed gas is allowed to flow through the highly hydrogen diluted raw material gas flow path 30 ′. Film formation is started by flowing a low dilution mixed gas into the low hydrogen dilution raw material gas flow path 33 '.

Then, a high frequency electric field is formed between both electrodes 31 'and 32', and the highly diluted mixed gas supplied to the high frequency electric field from the gas outlet 31a is excited into a plasma state by the energy of the high frequency electric field. As a result, Si crystal grains are intentionally generated in the plasma generation region P1, and the Si crystal grains are supplied from the gas outlet 32a to the plasma generation region P2 to perform amorphous film formation.
In the plasma generation region P2, a high-frequency electric field is formed between the positive electrode 32 'and the substrate 3 and the substrate carrier 6, and the low dilution mixed gas and Si crystal grains supplied from the gas outlet 33a are excited into a plasma state and deteriorated. An amorphous film having a low rate is formed on the substrate 3.

Further, in the plasma film forming method described above, the second plasma generation region P2 is always turned on to excite the plasma, and the first plasma generation region P1 is alternately turned ON / OFF, for example, as shown in FIG. Such a multilayer film can be formed.
That is, if the first plasma generation region P1 is first turned off to stop the excitation of the plasma, Si crystal grains are not generated from the highly diluted mixed gas. Therefore, an amorphous silicon layer is formed on the first layer S1 of the substrate 3. A film is formed. Thereafter, when the first plasma generation region P1 is turned on to excite the plasma, Si crystal grains are generated from the highly diluted mixed gas. Therefore, the second layer S2 of the substrate 3 contains Si crystal grains. An amorphous silicon layer is deposited.

  In the same manner, by alternately repeating OFF and ON of the first plasma generation region P1, an amorphous silicon layer is formed on the third layer S3 of the substrate 3, and an Si crystal grain is formed on the fourth layer. An amorphous silicon layer is formed, and an amorphous silicon layer is formed on the fifth uppermost layer S5. In the example shown in the figure, the multilayer film includes five layers S1 to S5, but a desired number of layers can be stacked by changing the number of ON / OFF times.

  Further, in the plasma film forming method described above, the high frequency electric field on the first plasma generation region P1 side is preferably set to a higher frequency than the second plasma generation region P2. As a specific example, since the frequency of the first plasma generation region P1 is set to 100 MHz and the frequency of the second plasma generation region P2 is set to 60 MHz, Si crystal grains can be generated with high efficiency. High-quality film formation with a lower deterioration rate is possible. In other words, the crystal grains of the source gas can be generated with high efficiency by such high frequency operation.

In the plasma film forming method described above, the first source gas included in the high hydrogen dilution source gas is a mixed gas with GeH ₄ , and the second source gas included in the low hydrogen dilution source gas is SiH ₄ . In the case of the mixed gas, silicon and germanium amorphous film formation layers or microcrystal film formation layers can be alternately formed into multiple layers by adjusting the plasma conditions such as the frequency of the high frequency power supply and ON / OFF.
That is, the first layer S1 in FIG. 10 is an amorphous silicon layer, the second layer S2 is an amorphous germanium layer, the third layer S3 is an amorphous silicon layer, the fourth layer S4 is an amorphous germanium layer, and the uppermost layer A multilayer film is formed in which the fifth layer S5 is an amorphous silicon layer, or the first layer S1 is a microcrystalline silicon layer, the second layer S2 is a microcrystalline germanium layer, and the third layer S3 is microcrystalline. It is also possible to form a multilayer film in which the silicon layer, the fourth layer S4 is a microcrystalline germanium layer, and the uppermost fifth layer S5 is a microcrystalline silicon layer.
Since the multilayer film as described above can be formed on the substrate 3, the composition adjustment of the film formation can be appropriately performed and used as an effective means for developing a new device.

Next, a specific example in which the plasma processing method described above is employed to realize a large area of the substrate 3 will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part similar to each embodiment mentioned above, and the detailed description is abbreviate | omitted.
11 and 12 are schematic configuration diagrams showing an application example to a CVD apparatus that employs the above-described plasma generation source 10B and forms a film on the substrate 3 having a large area.
In this application example, both ends of the positive electrode 32 'are connected to the first high-frequency power source 34 and the second high-frequency power source 35, respectively, and the negative electrode 32 is grounded at two locations.
In the plasma generation source 10B configured as described above, by applying the phase modulation method to the feeding method, it is possible to form a high-quality film on the large substrate 3 having a substrate width of 2 to 3 m, and the substrate 3 High-quality film formation can be performed in response to the increase in area.

Specifically, when high-speed phase modulation (about several tens of kHz) is performed, the position L to which the maximum voltage V is applied moves in the substrate width direction at a high speed, so that it is uniform in the plasma generation space of the plasma generation region P. Therefore, a uniform film can be formed on the film forming surface of the substrate 3.
Further, by performing low-speed phase modulation (for example, 1 Hz or less), the position L to which the maximum voltage V is applied moves in the substrate width direction at a low speed, so that plasma generation in the plasma generation space of the plasma generation region P is continuously performed. Can be turned ON / OFF. For this reason, the standing wave can move and the plasma generation region P can be swung, and when viewed at a certain place (fixed point), the plasma generation is in the same state as ON / OFF. A uniform film can be formed on the film forming surface.

The plasma generation source 10B described above indicates the area of the substrate 3 that can be formed by moving the substrate 3 in a direction perpendicular to the positive electrode 32 'and the negative electrode 31'. 4 can be easily expanded in the conveyance direction indicated by 4.
Further, by connecting in parallel the electrode units each including the positive electrode 32 'and the negative electrode 31' described above, that is, by arranging a plurality in parallel in the transport direction described above, the substrate 3 can be moved. However, it is possible to enlarge the film forming area and increase the area. In addition, the combination with such parallel arrangement of the electrode units and the movement of the substrate 3 described above makes it easier to cope with the increase in area.

In the application example described above, the negative electrode 31 'is simply grounded. However, as in the first embodiment (see FIG. 4), a substrate such as a DC power source or a low-frequency power source is applied to the substrate. Film formation control for increasing the plasma density on the three side may be performed.
Also in this embodiment, self-cleaning in the chamber 2 for removing the silicon film is possible as in the first embodiment described above.

Next, another specific example of realizing the large area of the substrate 3 by employing the above-described plasma processing method will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part similar to each embodiment mentioned above, and the detailed description is abbreviate | omitted.
In this specific example, in addition to generating two plasma generation regions P1 and P2, both plasma generation regions can be ON / OFF controlled by individual stub control.

In this case, the power supply system is provided with a first variable stub 37 and a second variable stub 38, and the variable capacitors 37a and 38a of both the variable stubs 37 and 38 are operated to obtain the capacitances CA and CB. By changing the impedance, each impedance ZS changes. When the impedance ZS changes in this way, as shown in FIG. 14, when the impedance (Im) increases, a phase delay occurs in the high frequency power supply, and conversely, when the impedance decreases, the phase of the high frequency power supply advances.
Therefore, if the phase difference is generated between the voltage 1 of the first plasma generation region P1 and the voltage 2 of the second plasma generation region P2 by operating the variable stubs 37 and 38, the two plasma generation regions P1 and P2 are changed. Can be turned on and off individually.

That is, two regions of plasma can be individually stub-controlled by a set of high-frequency power supplies 34 and 35, and further, gas can be supplied individually, so that a film forming method suitable for the film forming process can be selected and implemented. It becomes. The low-speed phase modulation also enables intermittent control to turn on / off the plasma simultaneously in two regions.
Accordingly, by providing a hydrogen plasma source and supplying silane gas to the non-plasma space, the radical concentration between the positive electrode 32 'and the substrate 3 can be controlled, so that high quality film formation can be performed.
Note that the specific example in this case can cope with the increase in size of the substrate 3 as in the specific example described above.

<Fourth Embodiment>
Next, a fourth embodiment will be described with reference to FIG. 9 for a plasma generation source which is a plasma film forming means using the plasma processing method according to the present invention. In addition, the same code | symbol is attached | subjected to the part similar to each embodiment mentioned above, and the detailed description is abbreviate | omitted.
This embodiment is different from the gas used in the third embodiment. That is, hydrogen gas is supplied instead of the highly diluted mixed gas, and a mixed gas of silane gas and hydrogen gas is used instead of the low diluted mixed gas.

  Specifically, hydrogen gas is introduced into the vacuum in the chamber 2 and a high-frequency electric field is applied to generate a hydrogen gas plasma in the first plasma generation region P1. Then, a mixed gas of the source gas is introduced and a high frequency electric field is applied to generate a plasma of the mixed gas in the second plasma generation region P2. Then, the first plasma generation region P1 is ON / OFF controlled, and hydrogen radicals generated in the first plasma control region P1 are intermittently supplied to the second plasma generation region P2 to form a film.

  In such a plasma film forming method, high quality film formation can be performed by intermittently supplying a combination of hydrogen radicals during film formation. That is, by intermittently supplying hydrogen radicals, a hydrogen abstraction reaction occurs on the film surface, so that the film is densified and a high-quality film can be obtained. Here, the intermittent supply will be specifically described. First, when the first plasma region P1 is turned on to excite the plasma of hydrogen gas and the second plasma region P2 is turned off, the first plasma generation region P1. The hydrogen radical treatment that generates a large amount of hydrogen radicals is performed. Next, when the first plasma region P1 is turned off and the second plasma region P2 is turned on, the plasma of the mixed gas is excited and film formation is performed in the absence of supply of hydrogen radicals. At this time, since hydrogen is extracted from the film surface, a dense and high-quality film can be obtained.

<Fifth Embodiment>
Next, a fifth embodiment of a plasma generation source that is a plasma film forming means using the plasma processing method according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part similar to each embodiment mentioned above, and the detailed description is abbreviate | omitted.
This embodiment is different from the third and fourth embodiments described above in the gas used. That is, a mixed gas of a raw material gas (silane gas) and hydrogen gas is supplied instead of the highly diluted mixed gas, and argon gas is used instead of the low diluted mixed gas.

  Specifically, a mixed gas of hydrogen gas and silane gas is introduced into the vacuum in the chamber 2 and a high-frequency electric field is applied to generate a plasma of the mixed gas, and in the vacuum in the chamber 2. Argon (Ar) gas is introduced, a high-frequency electric field is applied, a second plasma generation region P2 for generating argon gas plasma is provided, and film formation is performed by combining film formation with silane gas and argon ion treatment.

  In such a plasma film forming method, since film formation is performed by combining film formation with silane gas and argon ion treatment, hydrogen concentration control or band cap control on the outermost surface of the film that affects the film quality becomes possible. In this case, ON / OFF control of the first plasma generation region P1 is performed, and film formation processing for turning on the first plasma control region P1 and argon treatment for turning on the second plasma generation region are alternately performed. The intermittent process may be performed, or the film forming process and the argon process may be performed in parallel without performing the ON / OFF control.

<Sixth Embodiment>
In this embodiment, a specific example in which the above-described plasma processing method is employed to realize a large area of the substrate 3 will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part similar to each embodiment mentioned above, and the detailed description is abbreviate | omitted.
As shown in FIG. 15, the plasma film forming method employed here supplies two types of gas and forms two plasma generation regions, but forms a second plasma generation region P2. Different electrode structures.

  The plasma generation source 10 </ b> C includes a hollow box-shaped positive electrode 41 that forms the hydrogen gas flow path 40, a hollow box-shaped negative electrode 42 that forms the first plasma generation region P <b> 1 in the internal space, and the outside of the negative electrode 42. And a mesh positive electrode (positive electrode member) 44 disposed in the second plasma generation region P2 formed between the substrate 3 and the negative electrode 42. Composed. Note that the mesh positive electrode 44 capable of flowing gas may be employed as long as the gas can pass through the second plasma generation region P2 other than the mesh shape, for example. The positive electrode 42 is supplied with power from the first high frequency power supply 45A and the second high frequency power supply 46A, and the mesh electrode 44 is supplied with power from the first high frequency power supply 45B and the second high frequency power supply 46B.

  In the plasma generation source 10 </ b> C configured as described above, hydrogen gas is introduced into the vacuum in the chamber 2, a high frequency electric field is applied to the positive electrode 41, and hydrogen radicals excited by this hydrogen gas into a plasma state are converted into negative electrodes. Abundantly generated in the first plasma generation region P <b> 1 in 42. Further, a high frequency electric field is applied to the mesh positive electrode 44 to form the plasma generation region P2, and the silane gas is introduced into the plasma generation region P2 through the raw material gas flow path 43 different from the hydrogen gas. Due to the reaction with the abundant hydrogen radicals, a high quality film is formed on the film forming surface of the substrate 3.

The plasma generation source 10C that enables high-quality film formation in this way includes two plasma generation regions P1 and P2, each having independent high-frequency power supplies 45A and 46A and 45B and 46B. Plasma generation ON / OFF control can be performed by operating an independent power source.
Further, as shown in FIG. 7, the phase modulation method is applied to the feeding method of the high frequency power supplies 45A, 46A and 45B, 46B, and the voltages V1 and V2 are applied by applying the high speed phase modulation described in the second embodiment, for example. Since the position where the above acts moves at high speed, uniform plasma can be generated in the direction of the position L in the plasma generation spaces of the first and second plasma generation regions P1 and P2. For this reason, it is possible to form a high-quality film on a large substrate 3 having a substrate width of 2 to 3 m, and it is possible to cope with an increase in area of the substrate 3.

The plasma generation source 10C described above indicates the area of the substrate 3 that can be formed by the arrow 4 in the figure if the substrate 3 is formed while being transported and moved in the direction perpendicular to the positive electrode 41 and the negative electrode 42. It can be easily expanded in the transport direction shown.
In addition, by connecting in parallel the electrode units including the positive electrode 41 and the negative electrode 42 described above, that is, by arranging a plurality in parallel in the transport direction described above, the substrate 3 can be manufactured without moving. The film area can be increased to increase the area. In addition, the combination with such parallel arrangement of the electrode units and the movement of the substrate 3 described above makes it easier to cope with the increase in area.

In the application example described above, the negative electrode 42 is simply grounded. However, as in the first embodiment (see FIG. 4), a bias such as a DC power supply or a low-frequency power supply is applied to the substrate 3. Film formation control for increasing the plasma density on the side may be performed.
Also in this embodiment, self-cleaning in the chamber 2 for removing the silicon film is possible as in the first embodiment described above.

According to the plasma CVD apparatus using the plasma processing method described in each of the above embodiments, the plasma generated from the plasma generation source 10 continuously acts on the substrate 3 conveyed in a state facing the plasma generation source. Therefore, it is possible to perform processes such as etching, sputtering, and thin film formation on the entire surface of the substrate 3.
Accordingly, it is possible to perform a uniform film forming process or the like over the entire surface of the substrate 3 having a large area of, for example, a 3 m square class without providing the plasma generation source 10 having the same size as the substrate 3. As a result, when applied to a method for manufacturing a large-sized solar cell with a particularly large area, the productivity can be improved, the production cost can be greatly reduced, and a high-quality film-formed solar cell can be obtained. be able to.

In the above description, the substrate 3 is transported in one direction. However, the present invention is not limited to this, and the substrate 3 may be moved repeatedly in the front-rear direction. Further, since the substrate 3 and the plasma generation source 10 only need to move relative to each other, the substrate 3 may be fixed and the plasma generation source 10 may be moved. Furthermore, it is good also as a structure which both move.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.

It is a block diagram which shows 1st Embodiment of a plasma generation source as a plasma film-forming means using the plasma processing method concerning this invention, (a) shows the structural example using a pair of counter electrode, (b) Shows a modification using three counter electrodes. It is a figure which shows the structural example which applied the plasma generation source of FIG.1 (b) to the plasma CVD apparatus. It is a figure which shows the relationship between the voltage (V) at the time of the high frequency power supply application in FIG. 2, and a position (L). It is a figure which shows the structural example at the time of applying a bias, (a) is a bias application of a low frequency power supply, (b) is a bias application of DC power supply. 1 is a schematic diagram showing a configuration example of a plasma CVD apparatus as an embodiment of a plasma processing apparatus according to the present invention. It is a block diagram which shows 2nd Embodiment of a plasma generation source as a plasma film forming means using the plasma processing method concerning this invention. It is a figure which shows the structural example which applied the plasma generation source of FIG. 6 to the plasma CVD apparatus. It is explanatory drawing which shows the electrode longitudinal direction cross section of FIG. It is a block diagram which shows the 2nd-5th embodiment of a plasma generation source as a plasma film-forming means using the plasma processing method concerning this invention. It is sectional drawing which shows the structural example which formed the multilayer film. It is a figure which shows the structural example at the time of applying the plasma generation source of FIG. 10 to a plasma CVD apparatus. It is a figure which shows the relationship between the voltage (V) at the time of the high frequency power supply application in FIG. 11, and a position (L). It is a figure which shows the other structural example at the time of applying the plasma generation source of FIG. 10 to a plasma CVD apparatus. It is explanatory drawing which shows the relationship between the impedance (Im) of a variable stub, and the phase of a high frequency power supply. It is a block diagram which shows 6th Embodiment of a plasma generation source as a plasma film-forming means using the plasma processing method concerning this invention. It is a figure which shows the structural example at the time of applying the plasma generation source of FIG. 15 to a plasma CVD apparatus. It is a figure which shows the relationship between the voltage (V) at the time of the high frequency power supply application in FIG. 16, and a position (L).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma CVD apparatus 2 Chamber 3 Substrate 6 Substrate carrier 10, 10 ', 10A-10C Plasma generation source (plasma generation means)
11, 31, 41 Positive electrode 12, 32, 42 Negative electrode 13, 30, 40 Hydrogen gas flow path 14, 33, 43 Source gas flow path 15, 15 'Insulator 16 Power supply path 17 Electric wire 30' High hydrogen dilution source gas Flow path 31 'Negative electrode 32' Positive electrode 33 'Low hydrogen dilution source gas flow path 44 Mesh positive electrode P Plasma generation area P1 First plasma generation area P2 Second plasma generation area

Claims (22)

A plasma deposition method for producing a thin film of a source gas on a substrate by plasma chemical vapor deposition,
Hydrogen gas is introduced into a vacuum and a high frequency electric field is applied to generate hydrogen radicals excited in a plasma state, and the source gas is supplied from a system separate from the hydrogen gas. And the hydrogen radical are reacted in a plasma-free space to form a film on the substrate. The plasma film forming method according to claim 1, wherein the source gas is silane gas (SiH ₄ ). The plasma deposition method according to claim 1 or 2, wherein the substrate is heated to 500 ° C to 700 ° C. A plasma deposition method for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition,
A first plasma generation region for introducing a first source gas diluted with hydrogen into a vacuum and applying a high-frequency electric field to generate plasma of the first source gas;
Providing a second plasma generation region for introducing a second source gas diluted with hydrogen into a vacuum and applying a high-frequency electric field to generate plasma of the second source gas;
A method for forming a plasma, comprising: supplying crystal grains of the first source gas generated in the first plasma generation region to the second plasma generation region to form an amorphous film. 5. The plasma film forming method according to claim 4, wherein the second plasma generation region is turned on and the first plasma generation region is alternately turned on and off. 6. The plasma film forming method according to claim 4, wherein the high-frequency electric field has a higher frequency on the first plasma generation region side than on the second plasma generation region. 7. The plasma film forming method according to claim 4, wherein the first source gas and the second source gas are silane gas (SiH ₄ ). The plasma deposition method according to claim ₄ , wherein the first source gas is GeH ₄ and the second source gas is SiH ₄ . A plasma deposition method for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition,
A first plasma generation region for introducing a hydrogen gas into a vacuum and applying a high-frequency electric field to generate a plasma of the hydrogen gas;
Providing a second plasma generation region for introducing a mixed gas of hydrogen gas and source gas into a vacuum and applying a high-frequency electric field to generate plasma of the mixed gas;
The first plasma generation region is ON / OFF controlled, and hydrogen radicals generated in the first plasma control region are intermittently supplied to the second plasma generation region to form a film. Membrane method. A plasma deposition method for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition,
A first plasma generation region for introducing a mixed gas of hydrogen gas and source gas into a vacuum and applying a high-frequency electric field to generate plasma of the mixed gas;
Argon (Ar) gas is introduced into the vacuum, a high-frequency electric field is applied, and a second plasma generation region for generating the argon gas plasma is provided,
A plasma film forming method comprising forming a film by combining the film formation with the source gas and the argon ion treatment. 11. A plasma processing apparatus, comprising: a plasma film forming means for forming a film by the plasma film forming method according to claim 1 in a chamber provided with an adjustable internal pressure. A plasma processing apparatus for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition by providing a plasma film forming means in a chamber capable of adjusting an internal pressure,
The plasma film forming means is opposed to each other at a predetermined interval and extends and crosses the width direction of the substrate, and an insulator for insulating and covering the positive electrode and the negative electrode so as not to contact each other And a hydrogen gas flow path and a source gas flow path independently formed inside the insulator,
A plurality of feeding points are provided on the positive electrode and the negative electrode, and a high frequency electric field is applied to the hydrogen gas introduced between the positive electrode and the negative electrode to generate hydrogen radicals in which the hydrogen gas is excited into a plasma state. The plasma processing apparatus is characterized in that the source gas and the hydrogen radical are reacted in a plasma-free space to form a film on the substrate. The plasma processing apparatus according to claim 12, wherein a position of the insulator is variable together with the positive electrode and the negative electrode. A plasma processing apparatus for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition by providing a plasma film forming means in a chamber capable of adjusting an internal pressure,
The plasma film forming means includes a hollow box-shaped positive electrode in which a hydrogen gas flow path for introducing hydrogen gas into the internal space is formed, and a hollow box in which a plasma generation region is formed in the internal space and the positive electrode is accommodated A negative electrode having a shape, and a raw material gas channel formed outside the negative electrode,
A high frequency electric field is applied to the hydrogen gas introduced into the positive electrode to generate hydrogen radicals excited in a plasma state, and the source gas and the hydrogen radicals are free from plasma outside the positive electrode. A plasma processing apparatus configured to form a film on the substrate by reacting in space. A plasma processing apparatus for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition by providing a plasma film forming means in a chamber capable of adjusting an internal pressure,
The plasma film forming means forms a hollow box-shaped positive electrode in which a hydrogen gas flow path for introducing hydrogen gas into the internal space is formed, and forms a first plasma generation region in the internal space and accommodates the positive electrode. A hollow box-shaped negative electrode, a source gas flow path formed outside the negative electrode, and a positive electrode member disposed between the negative electrode and the substrate to allow gas flow. Equipped,
The first plasma generation region in the positive electrode and the second plasma formation region formed around the positive electrode member are each subjected to independent plasma generation ON / OFF control to form a film on the substrate. A plasma processing apparatus characterized by comprising: A plasma processing apparatus for forming a thin film of a source gas on a substrate by plasma chemical vapor deposition by providing a plasma film forming means in a chamber capable of adjusting an internal pressure,
The plasma film forming means forms a hollow box-shaped negative electrode in which a hydrogen gas flow path for introducing hydrogen gas into the internal space is formed, and forms a first plasma generation region in the internal space and accommodates the negative electrode. A hollow box-shaped positive electrode, and a raw material gas channel formed outside the positive electrode,
2. A plasma processing apparatus, comprising: a plasma film forming means configured to form a second plasma generation region between the positive electrode and the substrate to form a film on the substrate. The plasma processing apparatus according to claim 16, wherein a phase of a power feeding system connected to the positive electrode and the negative electrode is controlled. 18. The plasma processing apparatus according to claim 12, further comprising transport / moving means for relatively moving the plasma film forming means and the substrate during film formation. The plasma processing apparatus according to claim 12, wherein a plurality of the plasma film forming means are electrically connected in parallel. The plasma processing apparatus according to claim 12, wherein a bias is applied to the negative electrode side. A solar cell provided with the thin film formed with the plasma processing apparatus in any one of Claims 11-20. The manufacturing method of the solar cell using the plasma processing apparatus in any one of Claims 11-20.

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