JP2002012977A - Apparatus and method for surface treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for rapidly forming a film with superior uniformity even on a large area substrate of having such an area as 1 m×1 m to 2 m×2 m. SOLUTION: The surface treatment apparatus which is provided with a vacuum vessel 51 having an exhaust system, inside which the substrate is set, a gas introduction system for introducing a gas for discharge into the vacuum vessel 51, an electrode 52 arranged so as to face the substrate in the vacuum vessel, and a power supply system for supplying a high-frequency power to the electrode 52 and forming plasma by discharging the gas together with it, and which treats the surface of the substrate by utilizing the formed plasma, is characterized in that power supplying points 65a to 65p to the electrode 52 from the power supply system are located in the side of a boundary zone between a first face contacting with a space in which the plasma is formed and a second face which is a back face of the first face, out of the whole surface of the electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment apparatus and a surface treatment method for performing a predetermined treatment on the surface of a substrate using glow discharge plasma of a discharge gas. The present invention
In particular, the present invention relates to a surface treatment apparatus and a surface treatment method using reactive plasma that generates plasma by glow discharge of a discharge gas generated by high-frequency power having a frequency of 10 MHz to 300 MHz.

[0002]

2. Description of the Related Art Various processes are performed on the surface of a substrate using reactive plasma to produce various electronic devices.
It has already been put to practical use in fields such as SI (large-scale integrated circuit), LCD (liquid crystal display), amorphous Si-based solar cell, thin-film polycrystalline Si-based solar cell, photoconductor for copying machines, and various information recording devices.

[0003] The technical field of the above-mentioned surface treatment covers a wide variety of fields, such as thin film formation, etching, and surface modification, and all of them utilize the chemical action of reactive plasma. Representative examples of the apparatus and method relating to the generation of the reactive plasma are described in JP-A-8-325759 (Document 1) and A voltage uni.
formity study in large-area reactors for RF
Plasma deposition: L. Sansonnems, A.S. Pletze
r, D. Magni, A. A. Howling, Ch. Hollenste
in and J. P. M. Schmitt, Plasma Source Sc
i. Technol. 6 (1997), p. 170-178 (referred to as Reference 2).

Hereinafter, three cases, that is, three types of apparatus configurations and methods will be described with reference to FIGS.

(Conventional Example 1) First, as Conventional Example 1, a first apparatus described in Document 1 will be described with reference to FIG. Inside the vacuum vessel 1, a pair of electrodes for generating glow discharge plasma, that is, an ungrounded electrode 2 and a substrate heater 3 are provided.
Is disposed. The non-ground electrode 2 is mounted on the upper part of the vacuum vessel 1 via an insulator 5. A matching device 6 and a high-frequency power supply 7 for generating a predetermined high-frequency power are connected to the non-ground electrode 2 via a coaxial cable 8, and an output from the high-frequency power supply 7 is supplied to a power supply point 9 of the non-ground electrode 2. Is done. The power supply point 9 is located on the surface of the non-grounded electrode 2 on the atmosphere side, that is, the surface not in contact with the space 10 in which plasma is generated. The frequency of the power output from the high frequency power supply 7 is 13.56 MH
z is commonly used.

The vacuum vessel 1 has a discharge gas introduction pipe 11.
And a cylinder (not shown), and monosilane (SiH ₄ ) is supplied into the vacuum vessel 1 from the cylinder. A vacuum pump 13 is connected to the vacuum vessel 1 via an exhaust pipe 12 so that the gas in the vacuum vessel 1
Through the vacuum pump 13. The substrate 14 is set on the ground electrode 4 and is heated to a predetermined temperature by the substrate heater 3 and a substrate heater power supply 15 connected to the substrate heater 3.

[0007] Next, the substrate 1 is
The case where an amorphous Si (a-Si) film is formed on the substrate 4 will be described. First, the substrate 14 is placed on the ground electrode 4 via a substrate loading / unloading gate (not shown), and the vacuum pump 13 is driven to evacuate the vacuum vessel 1 to a pressure of 1 × 10 ^−7.
Exhaust to Torr. Further, the temperature of the substrate 14 is set to a predetermined temperature using the substrate heater 3 and the substrate heater power supply 15. Next, a predetermined amount of, for example, monosilane gas is supplied into the vacuum vessel 1 through the discharge gas introducing pipe 11, the pressure in the vacuum vessel 1 is maintained at 0.05 to 0.5 Torr, and the power supply system, that is, the high-frequency power source 7, 6 and coaxial cable 8
Is used to supply power to the pair of non-ground electrodes 2 and the ground electrode 4. Thereby, a glow discharge plasma is generated between the non-ground electrode 2 and the ground electrode 4. When the monosilane gas is turned into plasma, SiH ₃ , SiH
₂ , radicals such as SiH are diffused by a diffusion phenomenon and are adsorbed and deposited on the surface of the substrate 14, whereby a-Si
A film is formed.

In addition, by adjusting the mixing ratio of the discharge gas such as the flow ratio of SiH ₄ and H ₂ , the pressure, the substrate temperature, the plasma generation power, etc. as the film formation conditions, not only a-Si but also fine It is known that crystalline Si and polycrystalline Si can be formed into films.

In addition, an etching effect is obtained as a discharge gas.
Gas, for example SF₆, SiCl ₄, CF₄And NF
₃Using an etching gas such as
It is known that an etching process can be performed.

(Conventional Example 2) Next, as Conventional Example 2, a second apparatus described in Document 1 will be described with reference to FIGS. However, the same members as those in FIG. 22 are denoted by the same reference numerals and description thereof is omitted. Reference numeral 21 in the figure indicates a gate valve provided on the side wall of the vacuum vessel. The substrate 14 is taken in and out of the gate valve 21. Inside the insulator 5 located above the vacuum vessel 1, a non-grounded electrode 2 having a hollow inside is disposed. The lower surface (front surface) 2a of the ungrounded electrode 2, that is, the space 10 in which plasma is generated has a diameter of 0.5 mm.
Many gas ejection holes 2b have a hole interval of 10 to 15 mm
It is formed with. On the upper surface of the non-grounded electrode 2, an opening 2c for a discharge gas is formed. The discharge gas introduction pipe 11 b is connected to the opening 2 c of the non-ground electrode 2 via a connection member 23. For example, monosilane gas (SiH ₄ ) is supplied from the discharge gas introduction pipe 11 b into the non-grounded electrode 2. On the non-ground electrode 2,
A power distributor 25 that branches the output of the high-frequency power supply into a plurality of power supplies is arranged.

A glow discharge plasma is generated in the vacuum vessel 1 by the non-ground electrode 2 and the ground electrode 4. The shape of the non-grounded electrode 2 is a rectangular or square plate-like member (thickness: about 60 mm, about 500 mm × 500 mm to about 1000 mm × 1000 mm), and is made of stainless steel. A required power is supplied to the non-grounded electrode 22 from a power supply system including the high-frequency power supply 7, the matching device 6, and the power distributor 25.

As shown in FIG. 24, the power distributor 25 has a cylindrical connection port 26 disposed at the center, four strip-shaped branch ports 27 extending radially from the connection port 26, and four connection ports. Cylindrical members 28a, 28b, 28c,
28d.

Note that reference numerals 9a, 9b, 9c,
9d indicates power supply points. The gas in the vacuum vessel 1 is discharged from a vacuum pump 13 through an exhaust pipe 12. The substrate 14 is placed on the ground electrode 4 with the gate valve 21 opened, and is heated to a predetermined temperature by the substrate heater 3 and the substrate heater power supply 15.

Next, using the apparatus shown in FIG.
The case where the i film is formed will be described. First, the gate valve 21 is opened, the substrate 14 is placed on the ground electrode 4, and then the gate valve 21 is closed. Subsequently, the vacuum pump 13 is driven to ^{generate a} pressure of 1 × 10 ⁻⁷ T in the vacuum vessel 1.
Exhaust to about orr. Next, the temperature of the substrate 14 is set to a predetermined temperature using the substrate heater 3 and the substrate heater power supply 15. Further, the discharge gas introduction tubes 11a, 1
1b, for example, a predetermined amount of monosilane gas is supplied,
The pressure in the vacuum vessel 1 is kept at 0.05 to 0.5 Torr, and a pair of electrodes,
Power is supplied to the ground electrode 4. Thereby, both electrodes 2,
Glow discharge plasma is generated between the four.

When the monosilane gas is turned into plasma, radicals such as SiH ₃ , SiH ₂ , and SiH existing therein are diffused by a diffusion phenomenon, and are adsorbed and deposited on the surface of the substrate 14 to thereby form a-Si. A film is formed. The film forming conditions include a mixing ratio of a discharge gas, for example, Si
By optimizing the flow ratio of H ₄ and H ₂ , pressure, substrate temperature, plasma generation power, etc., not only a-Si,
It is known that microcrystalline Si and polycrystalline Si can be formed into films. It is known that a predetermined etching process can be performed on the surface of the substrate 14 by using an etching gas such as SF ₆ , SiCl ₄ , CF _4, and NF ₃ as a discharge gas.

(Conventional Example 3) Next, as a conventional example 3, an apparatus described in Document 2 will be described with reference to FIGS. 25 and 26. FIG. However, the same members as those in FIGS. 22 and 23 are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 31 denotes a high-frequency oscillator, which is connected to the matching unit 6 via a high-frequency power amplifier 32.
Here, the high-frequency oscillator 31 and the high-frequency amplifier 32 constitute a high-frequency power supply. A vacuum current introducing terminal 33 is provided on the wall surface of the vacuum vessel 1, and the non-ground electrode 2 and the matching box 6 are connected by a coaxial cable 8 passing through the introducing terminal 33. In the vacuum vessel 1, glow discharge plasma is generated by a pair of electrodes, that is, the ungrounded electrode 2 and a wall (bottom surface) 34 on which the substrate 14 is installed. The non-grounded electrode 2 is supplied with high-frequency power from the high-frequency power supply via a vacuum current introduction terminal 33, a coaxial cable 8 and a matching device 6. In this case, the power supply frequency is 70 MHz
It is. An H-shaped power supply line 35 is formed on the rear surface of the non-grounded electrode 2 (the surface not in contact with the space where plasma is generated) as shown in FIG. The power supply points 9a, 9b, 9c, 9
d is formed.

With such an apparatus, a size of 350 mm
Table 1 below on a × 450 mm glass substrate (1 mm thick)
The a-Si film is formed under the film forming conditions shown in FIG.

[0019]

[Table 1]

As a result, an a-Si film having a film thickness distribution of ± 18% is obtained.

[0021]

By the way, the above-mentioned surface treatment technique, that is, the surface treatment apparatus and the surface treatment method, are based on LC
In all industrial fields such as D, LSI, electronic copiers and solar cells, needs for large area and high speed processing such as reduction of product cost due to productivity improvement and improvement of performance (specification) such as large area wall mounted TV Is growing year by year.

Recently, in order to meet the above-mentioned needs, not only in the industry but also in academic societies, especially in plasma CVD (chemical vapor deposition) technology and plasma etching technology, high-density plasma using a power supply in the VHF band (30 MHz to 300 MHz). Research on high-speed film forming technology and high-speed plasma etching technology of CVD is active.

However, the prior art still has the following problems. 1) First, there is an increase in the area of surface treatment using plasma (improvement in productivity and performance). As the apparatus and method for plasma surface treatment, the techniques shown in FIGS. 22 to 26 described above are used. According to the study of the present inventors, according to the conventional technique, for example, when an a-Si film is formed, when the substrate area is about 50 cm × 50 cm, as shown in FIG. 20, the substrate area is 100 cm × 100 cm. In this case, as shown in FIG. 21, as the power supply frequency increases,
It turned out that there is a problem that the film thickness distribution is extremely bad.

Generally, a film thickness distribution of ± 5% in the LCD field and a film thickness distribution of ± 10% in the solar cell field are one index for practical use. Therefore, in the prior art, except for the power supply frequency of 13.56 MHz, the substrate area is 0.5 m ×
There is a problem that the 0.5 m class or 1 m × 1 m class cannot be put to practical use.

2) Second, there is an increase in the speed of surface treatment (improvement in productivity). In order to increase the speed of the surface treatment technique using plasma, it is desired to increase the power supply frequency for plasma generation from 13.56 MHz, which has been practically used, to about 50 to 150 MHz, which is about 4 to about 10 times. ing.

If the plasma density increases its frequency,
It increases with the increase. That is, about 4 to about 10
If it is increased twice, the film forming speed is also increased by the amount corresponding to the increase. However, as shown in FIGS. 19A and 19B, when the power supply frequency for plasma generation is increased,
It has been found that there is a problem that the film thickness distribution is significantly deteriorated.

The reason is that when the frequency becomes high, the wavelength of the wave and the length of the propagation path of the power supply system, that is, the propagation path from the high-frequency power source to the electrode and the length of the propagation path on the electrode become approximately equal. Wave interference phenomenon (interference also with reflected waves)
Is generated, and the spatial uniformity of the plasma density cannot be maintained.

Another reason is that the conventional 13.56 is used.
Although it occurs at a frequency of MHz, it is considered that the skin effect, which is a phenomenon peculiar to a high-frequency radio wave, becomes more remarkable when the skin effect is 50 MHz to 150 MHz. That is, the skin effect is a phenomenon in which a high-frequency current appears only near the surface of a conductor, and the surface depth δ at which the current flows is δ = (3.14 × f · μ · σ) ^−0.5, where f : Frequency, μ: magnetic permeability, σ: electrical conductivity. For example, when the conductor is copper, its surface depth is 13.5.
About 19 μm at 6 MHz, about 1 at 50 MHz to 60 MHz
It is about 5.8 μm at 0 μm and 150 MHz. Therefore,
In the surface treatment technique using plasma in the VHF band (30 MHz to 300 MHz), spatial uniformity of plasma density can be maintained due to an increase in impedance and non-uniformity in a power supply propagation path from a high frequency power supply to an electrode. It may be gone.

Therefore, it is extremely difficult and impossible to improve the plasma surface technology by increasing the frequency of the plasma power supply for a large area substrate of 1 m × 1 m to 2 m × 2 m required for improving productivity and reducing costs. Have been. Since the plasma density increases almost in proportion to the frequency of the power supply for plasma generation, such research has been actively conducted in related technical field societies, but there has been no successful example of increasing the area.

The present invention has been made in order to solve the above-mentioned problems, and has a large frequency even for a substrate having a size larger in each step than the conventional one, for example, a large area substrate of 1 m × 1 m to 2 m × 2 m class. It is an object of the present invention to provide a surface treatment apparatus and a surface treatment method which use ultra-high frequency (VHF) and have high speed and excellent uniformity.

[0031]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, there is provided a vacuum vessel having an exhaust system in which a substrate is set, and a discharge vessel in the vacuum vessel. A gas introduction system for introducing a gas for use, an electrode disposed in the vacuum vessel so as to face the substrate, and a power for supplying high-frequency power to the electrode to discharge the gas for discharge and generate plasma. In a surface treatment apparatus comprising a supply system and using a generated plasma to treat a surface of a substrate arranged in a vacuum vessel, a power supply point to an electrode by the power supply system is provided on an entire surface of the electrode. Among them, the first surface is in contact with a space in which the plasma is generated, and the second surface, which is the back side of the first surface, is located on the side surface of the boundary.

Similarly, in order to achieve the above-mentioned object, a second aspect is provided.
The present invention provides a vacuum vessel provided with an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and a substrate facing the substrate in the vacuum vessel. It has an electrode arranged, a first ultra-high frequency power supply and a second ultra-high frequency power supply independent of the ultra-high frequency power supply, supplies high-frequency power to the electrode to discharge a discharge gas to generate plasma. And a power supply system, which is a surface treatment apparatus that treats the surface of a substrate disposed in a vacuum vessel using generated plasma, wherein the electrode has a square shape,
A plurality of first power supply terminals connected to an output circuit of the first ultrahigh-frequency power supply are attached one by one to a first side surface, which is one side surface of the electrode, at equal pitch intervals, and
The second side, which is the other side opposite to the first side, generates ultra-high-frequency power having substantially the same frequency as the output frequency of the first ultra-high-frequency power supply at equal pitch intervals. It has a configuration in which a plurality of second power supply terminals connected to the output circuit of the ultrahigh frequency power supply are attached one by one.

It should be noted that, in claim 2 (the same applies to other claims), the "equal pitch interval" means that not only the same pitch interval but also the substantially equal pitch interval is included.

[0034] Similarly, in order to achieve the above object, claim 3
The invention relates to a vacuum vessel having an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and an electrode arranged at a predetermined position in the vacuum vessel. And a high-frequency power supply having two outputs and changing the phase difference between the two outputs of the high-frequency power in a sawtooth manner with time, supplying high-frequency power to the electrodes to discharge a discharge gas to generate plasma. And a power supply system for processing the surface of the substrate using the generated plasma, wherein the electrode has a rectangular shape, the first side is one side of the electrode And a plurality of power supply points connected to the output circuit of the high-frequency power supply are mounted one by one on the second side surface, which is the other side surface opposite to the first side surface, at equal pitch intervals. It has the structure of.

Similarly, in order to achieve the above object, the invention according to claim 4 is characterized in that, according to claims 1 to 3, a coaxial cable is used for supplying power to a power supply point of an electrode by a power supply system. I have.

Similarly, in order to achieve the above object, the present invention provides
The invention according to claims 1 to 3 has a configuration in which the frequency of the high-frequency power belongs to the HF band to the VHF band of 10 MHz to 300 MHz. Here, the frequency of the high-frequency power is defined as described above. If the frequency is less than 10 MHz, the electron temperature is high, a high-quality Si-based thin film cannot be obtained, the plasma density is low, and the speed of the surface treatment is low. Therefore, the application value is low, and the frequency is 300M
If the frequency exceeds Hz, a coaxial cable is not used for the power transmission means, and a waveguide must be used, which is not practical.

[0037] Similarly, in order to achieve the above object, a sixth aspect of the present invention is provided.
The power supply system according to claim 2, wherein the power supply system branches at least one high-frequency power supply that generates high-frequency power and an output of the high-frequency power supply into a number corresponding to the number of the plurality of power supply points. One power splitter, at least one matching device arranged between the high-frequency power source and at least one power splitter via a high-frequency power transmission coaxial cable, and branched by the power splitter And a plurality of stranded coaxial cables for guiding high-frequency power to each of the power supply points.

[0038] Similarly, to achieve the above object, the present invention provides a seventh aspect.
According to the invention, the apparatus according to the first to sixth aspects has a configuration in which any one of an amorphous Si-based thin film, a microcrystalline Si-based thin film, and a polycrystalline Si-based thin film is formed.

Similarly, in order to achieve the above-mentioned object, the present invention comprises
The invention according to claim 1, wherein the electrode has a rectangular shape, and the substrate processed using plasma is for a solar cell, or for a liquid crystal display, or for a large-scale integrated circuit. It has a configuration to be a substrate.

Similarly, in order to achieve the above object, the present invention provides
The invention relates to a vacuum vessel having an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and an electrode arranged at a predetermined position in the vacuum vessel. And a power supply system for supplying high-frequency power to the electrode to generate a plasma by discharging a discharge gas, wherein a surface treatment method for processing the surface of the substrate using the generated plasma. Is provided with a power supply point on the side surface thereof, and power is supplied to the power supply point using the power supply system.

According to another aspect of the present invention, there is provided a vacuum vessel having an exhaust system in which a substrate is set and a discharge gas for introducing a discharge gas into the vacuum vessel. It has an introduction system, an electrode arranged at a predetermined position in a vacuum vessel, and at least two first and second super-high-frequency power supplies that generate high-frequency power independent of each other, and supplies high-frequency power to the electrodes. And a power supply system for generating a plasma by discharging a discharge gas to generate a plasma by using the generated plasma, a surface treatment method for treating the surface of the substrate, the shape of the electrode Is a square,
A first plurality of power supply terminals are attached at equal pitch intervals to a first side surface, which is one side surface of the electrode, and a second plurality of power supply terminals are attached to a second side surface, which is the other side opposite to the first side surface. Are attached at equal pitch intervals, and the output circuit of the first ultra-high frequency power supply and the first plurality of power supply terminals are connected to each other by one.
The output circuit of the second ultrahigh frequency power supply and the second plurality of power supply terminals are connected one by one by a coaxial cable.

Similarly, in order to achieve the above object, the present invention provides
According to a first aspect of the present invention, a vacuum vessel having an exhaust system in which a substrate is set, a discharge gas introducing system for introducing a discharge gas into the vacuum vessel, and a predetermined position in the vacuum vessel are provided. An electrode, and a high-frequency power source that changes the phase difference between the two outputs and the high-frequency power of the two outputs temporally in a sawtooth manner; supplies high-frequency power to the electrode to discharge a discharge gas; A surface treatment method for treating the surface of a substrate using generated plasma by using a surface treatment apparatus having a power supply system for generating the electrode, wherein the shape of the electrode is square, and one side surface of the electrode. The first plurality of power supply terminals are attached to the first side face at equal pitch intervals,
A second plurality of power supply terminals are attached at equal pitch intervals to a second side surface, which is the other side surface opposite to the side surface, and a first output circuit and a second output circuit of the ultra-high frequency power supply are respectively connected to the second side surface. The power supply terminals are connected to the first and second plurality of power supply terminals one by one by a coaxial cable.

Similarly, in order to achieve the above object, a first aspect of the present invention is described.
The invention according to claim 2 uses the ultra-high frequency power supply according to claims 9 to 11, wherein the ultra-high frequency power supply oscillates from 10 MHz to 300 MHz and supplies required power, and uses at least one matching unit and a plurality of coaxial cables. 10M of power supply
The output power of Hz to 300 MHz is supplied to the power supply point.

Similarly, in order to achieve the above object, a first aspect of the present invention is described.
The invention according to claim 3 is the method according to claims 9 to 12, wherein at least monosilane gas is used as the discharge gas to form the amorphous S.
One of an i-based thin film, a microcrystalline Si-based thin film, and a polycrystalline Si-based thin film is formed.

Similarly, in order to achieve the above-mentioned object, a first aspect of the present invention is provided.
The invention according to claim 4 is the method according to claims 9 to 13, wherein at least a monosilane gas is used as a discharge gas.
One of an i-based thin film, a microcrystalline Si-based thin film, and a polycrystalline Si-based thin film is formed.

Similarly, in order to achieve the above object, a first aspect of the present invention is described.
The invention of 5 is provided with a vacuum vessel having an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and a predetermined position in the vacuum vessel. An electrode and a high-frequency power supply that changes the phase difference between the two outputs and the high-frequency power of the two outputs temporally in a sawtooth manner. The high-frequency power is supplied to the electrode to discharge a discharge gas and generate plasma. A surface treatment method for treating the surface of a substrate using generated plasma by using a surface treatment apparatus having a power supply system for generating, wherein the shape of the electrode is square, and four sides of the electrode are formed. One of them is the first
And a plurality of power supply points connected to the power supply system are respectively installed on the second side face opposite to the first side face, and the power supply points are installed on the first side face and the second side face, respectively. A first output and a second output of the high-frequency power supply are connected to power supply points, respectively, so that two powers whose phases change from moment to moment are supplied.

[0047]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors set a power supply point for supplying power to an ungrounded electrode of a pair of parallel plate electrodes on a side surface of the electrode, that is, a front surface in contact with a plasma generation space of the ungrounded electrode. It was installed at the boundary between the (lower surface) and the rear surface (upper surface) on the back side to create a method for supplying the power. In order to demonstrate this, a square-shaped electrode was used as a pair of parallel plate electrodes, and an experiment of plasma generation and an amorphous silicon film formation experiment using monosilane gas were performed. As a result, the VHF band (30 MHz), which had no success in the prior art,
Plasma having a uniform spatial distribution could be generated with a large area plasma capable of supporting a 1 m × 1 m class substrate at (z to 300 MHz). Also, 1m × 1 which had no success in the prior art
An amorphous silicon film having a film thickness distribution of ± 5 to 20% was formed on a glass substrate having an area of m.

The reason why the conventional problem can be solved by the new idea is considered as follows. In the prior art,
The high-frequency current output from the high-frequency power supply is shown in FIG.
As shown in (A) and (B), the power flowed from the power supply point 9 to the front surface through the rear surface of the non-grounded electrode 2 to the side surface. However, it is considered that the new method realizes a current flow distribution that propagates from the position near the plasma generation space on the side surface of the ungrounded electrode to the surface at the front central portion as shown in FIG. Can be Therefore,
Although the potential distribution in the plasma space in the prior art was as shown in FIG. 14, it is considered that the substantially uniform potential distribution was obtained by the new method as shown in FIG.

In order to realize the above-described new method, a coaxial cable having a single core wire is conventionally used as a power supply line for supplying high-frequency power supplied from a high-frequency power supply to an ungrounded electrode. However, the present inventors have created a stranded coaxial cable having a configuration in which an outer conductor 38 is formed outside a stranded core wire 36 via an insulator 37 as shown in FIG. Then, I obtained a new finding that the impedance is large except for the coaxial cable having a stranded core wire, Joule heat is generated, and power supply is impossible. That is, when the coaxial cable has one core wire, the coaxial cable in the vacuum vessel becomes high in temperature of 400 ° C. or more due to Joule heat (may be disconnected), but when the number of core wires is increased to four or more. The temperature of the coaxial cable became approximately 100 ° C. or less.

In order to realize the above-described new method, a new means as shown in FIGS. 5 and 6 has been devised as a method of electrically connecting the coaxial cable and the non-grounded electrode. The details of these configurations will be described in the section of [Example] described later.

That is, in FIG. 5 and FIG.
6. As a method for connecting the stranded wire type coaxial cable 67a composed of the insulator 37 and the outer conductor 38 to the non-grounded electrode 52, a metal cylindrical body 73 fixed to the non-grounded electrode 52 is used.
a and the metal cylinder 73 using a metal bolt 74 or the like.
The core wire 36 of the stranded coaxial cable is pressed against the inner wall 75a of FIG.

Further, the present inventors have proposed a method for increasing the size of a substrate,
In order to cope with super large size of m × 1m to 2m × 2m,
As shown in FIGS. 3 and 4, a plurality of first power supply locations are provided at substantially equal pitch intervals on one side, ie, the first side, of a rectangular non-grounded electrode constituting a pair of parallel plate electrodes. Is installed, and a plurality of second power supply points are installed at substantially equal pitch intervals on the other side parallel to and opposed to the above-described side, and two high-frequency power sources that are independent of each other, that is, the first And a second high-frequency power supply, and a VHF class (30M) is supplied from the first high-frequency power supply to the first power supply point.
Hz to 300 MHz), for example, a power of 70 MHz, and the second power supply point is supplied from the second high frequency power supply to a frequency substantially equal to that of the first high frequency power supply, for example, 6 MHz.
A new method of generating a plasma between the pair of parallel plate electrodes described above by supplying power of 0 MHz to 80 MHz has been created.

To demonstrate the new method described above,
Monosilane gas (SiH _Four) And 1mx
Form amorphous silicon film on 1m glass substrate
An experiment was performed. As a result, the first high-frequency power supply and the
In the case where the first power supply point or the like is used, as shown in FIG.
Such a film thickness distribution, that is, the side close to the first power supply point
The film thickness is large, and the lateral direction of the ungrounded electrode (X-axis direction in FIG. 4)
It has been found that the film thickness becomes thinner as it goes to the direction.
Further, the second high-frequency power supply and the second power supply location
Is used, the film thickness distribution as shown in FIG.
That is, the film thickness on the side close to the second power supply point is thick,
It is said that the film thickness becomes thinner as it goes to the lateral direction of the ground electrode
Obtained knowledge.

Then, power is independently supplied from the first and second high-frequency power sources to the first and second power supply locations, respectively, and amorphous silicon is formed on the 1 m × 1 m glass substrate. 12A and 12B, that is, a good film thickness distribution with uniformity is obtained as shown in FIG. 12C. The reason why the film thickness distribution with good uniformity is formed is that the first and second high-frequency power supplies supply the powers that are independent of each other to the first and second power supply locations, so that the radio frequency interference is prevented. No phenomenon or standing wave is generated, and as a result, as shown in FIG. 17, it is considered that the potential distribution in the plasma space is kept substantially uniform as shown in FIG.

When the first and second high frequency power supplies are not independent, for example, the first high frequency power supply is
And power is supplied to the second power supply point, and 1 m × 1 m
It has also been found that when amorphous silicon is formed on the glass substrate described above, the film thickness distribution is not uniform as shown in FIG. The reason is that since high-frequency power is supplied from two different directions, the electric fields generated by the electrodes interfere with each other, or a standing wave is generated, and the power propagated from the two directions is opposite to each other. It is also conceivable that the reflected wave is fed back to the oscillator constituting the high-frequency power supply via the power supply line, and the function of the oscillator is significantly reduced.

Further, the shape of the electrode is rectangular, and one of the four side surfaces of the rectangular electrode, ie, the first side surface, and the side surface parallel to the first side surface, ie, the second side surface, A plurality of power supply points connected to the power supply system are respectively provided, and a high-frequency power supply that has two outputs to the high-frequency power supply and that temporally changes the phase difference between the two high-frequency powers in a saw-tooth shape is provided. And a power supply point installed on the first side surface and the second side surface, the second output and the second output of the high-frequency power supply for changing the phase difference of the high-frequency power of the two outputs temporally in a sawtooth manner. The first output and the second output are connected to supply two electric powers whose phases change from moment to moment.

As a result, as shown in FIGS. 18A and 18B, the two powers supplied from the first and second power supply points propagate in directions that collide with each other to generate a standing wave. Without this, the temporal average value has a substantially uniform spatial distribution. FIG. 18A shows that the two-output phase variable high-frequency oscillator 42 is connected to the non-ground electrode 39 via the first high-frequency amplifier 43a and the second high-frequency amplifier 43b when the phase difference changes from time to time. FIG. 3 is an overall view of a case where a first power supply point 40a and a second power supply point 40b are respectively provided. FIG. 18B is a characteristic diagram showing the relationship between the square of the composite voltage and the distance between the power supply points.

However, if the phase difference between the two high-frequency powers is fixed to, for example, 0 °, as shown in FIGS. 19A and 19B, interference occurs to form a standing wave. Here, FIG. 19A shows that, when the phase difference is 0 °, the two-output phase variable high-frequency oscillator 42 is connected to the first high-frequency amplifier 43a and the second high-frequency amplifier 43a.
FIG. 3 is a general view showing a case where the first power supply point 40a and the second power supply point 40b of the non-ground electrode 39 are respectively connected to the high-frequency amplifier 43b of FIG. In FIG. 19A, the waveform (a) is the voltage W1 (standing wave) of the first power.
And the waveform (b) is the voltage W2 (standing wave) of the second power
Is shown. FIG. 19B is a characteristic diagram showing the relationship between the square of the composite voltage and the distance between the power supply points.

[0059]

Embodiments of the present invention will be described below. In the following description, as an example of a surface treatment apparatus and a surface treatment method, an apparatus and a method for producing an amorphous silicon (a-Si) thin film necessary for producing a solar cell are assumed. However, it goes without saying that the subject of the invention of the present application is not limited to the apparatus and method of the above specific example.

(Embodiment 1) Referring to FIGS.
An apparatus and a method according to the first embodiment will be described. First of all,
The configuration will be described. Reference numeral 51 in the figure indicates a vacuum container. This
Glow discharge, glow discharge plasma
A pair of electrodes for generating the
And a ground electrode 54 having a built-in substrate heater 53
I have. The non-ground electrode 52 includes insulators 55a, 55b,
Attached to the upper portion of the vacuum vessel 51 via
You. The lower side of the non-grounded electrode 52, that is, plasma is generated
The lower surface A on the lower side in contact with the space 56 is
Many gas blowing holes 57 of about mm
mm. The upper side of the non-ground electrode 52
The upper surface B is provided with a cylinder (see FIG.
(Not shown). Vacuum volume from this cylinder
For example, monosilane (SiH ₄) Is supplied
You.

A first exhaust pipe 59 is provided in the vacuum vessel 51.
a is connected to the first vacuum pump 40a through the second exhaust pipe 59b, and the second vacuum pump 40a is connected through the second exhaust pipe 59b.
b is connected. The gas in the vacuum vessel 51 passes through the exhaust pipes 59a, 59b to the vacuum pumps 40a, 4b.
0b. The substrate 61 is placed on the ground electrode 54 and heated to a predetermined temperature by a substrate heater 53 and a substrate heater power supply 62 connected to the substrate heater 53. The ground electrode 54 is fixed to a support 63. A gate valve 64a for taking in and out the substrate is provided on a side wall of the vacuum vessel 51 corresponding to the height of the substrate 61.
64b are provided.

The side surface (first side surface) of the ungrounded electrode 52, that is, one side surface (first side surface) at a position slightly separated from the periphery of the lower surface A of the ungrounded electrode 52 in contact with the space 56 is shown in FIGS. As shown in FIG. 4, a plurality of power supply points 65a,
65b, 65c, 65d, 65e, 65f, 65f, 6
5g and 65h are located. In addition, a second side surface of the non-ground electrode 52 facing in parallel with the first side surface has a structure shown in FIG.
As shown in FIG. 4, a plurality of power supply points 65i,
65j, 65k, 65l, 65m, 65n, 65o, 6
5p is located. As shown in FIGS. 1 to 3, a plurality of current introduction terminals 66 are provided on the wall surface of the vacuum vessel 51.
a, 66b, 66c, 66d, 66e, 66f, 66
g, 66h and a plurality of current introduction terminals 66
i, 66j, 66k, 66l, 66m, 66n, 66
Groups of o and 66p are provided to face each other.

The power supply location 65a of the ungrounded electrode 52
~ 65p include a plurality of stranded coaxial cables 67a,
67b, 67c, 67d, 67e, 67f, 67f, 6
7g, 67h, 67i, 67j, 67k, 67l, 67
m, 67n, 67o, and 67p are connected respectively. The stranded coaxial cables 67a to 67h are connected to the first power distributor 69a and the first matching unit 70 via the current introduction terminals 66a to 66h and the coaxial cables 68a to 68h, respectively.
a and the first high frequency power supply 71a. Further, the stranded coaxial cables 67i to 67p
Are the current introduction terminals 66i to 66p, the coaxial cable 6
8i to 68p are electrically connected to the second power distributor 69b, the second matching unit 70b, and the second high-frequency power supply 71b in this order.

The stranded coaxial cables 67a to 67h
As shown in FIG. 7, external conductors 38 are provided outside a stranded wire (core wire) 36 made of a plurality of wires via an insulator 37.
Is formed. Take two stranded coaxial cables 67a, 67b as an example.
The 67b and the non-ground electrode 52 are connected as shown in FIGS.

Focusing on the cable 67a, in order to electrically connect the cable 67a to the side surface of the non-grounded electrode 52, a metal cylindrical body fixed to the side surface with an insulator 72 interposed therebetween. The stranded wire type coaxial cable 6 is attached to the inner wall 75 of the metal cylindrical body 73a using a metal bolt 73a and a metal bolt 74.
The stranded wire 7a is press-contacted to form a power supply location 65a. The path of the high-frequency current from the stranded wire 36 to the non-ground electrode 52 is formed by the inner wall 75 of the metal cylinder 73a.
It is composed of a screw portion 76 of the cylindrical body 73a and a screw portion 77 provided on the non-ground electrode 52 for fixing the cylindrical body 73a. Reference numeral 78 in FIG. 5 indicates a bolt, reference numeral 79 in FIG. 6 indicates a screw portion formed on the metal cylinder 73a, and reference numeral 74a indicates a screw portion of the bolt 74.

In FIG. 6, the case where the stranded wire type coaxial cable 67a is electrically connected to the side surface of the ungrounded electrode 52 has been described, but the other stranded wire type coaxial cables 67b to 67p and the side surface of the ungrounded electrode 52 are electrically connected. The same applies to the case of connecting to. Further, metal cylinders 73b to 73p are also provided at connection points of these cables 67b to 67p with the non-grounded electrode 52, respectively.

The first and second power distributors 69
Although a and 69b can be distributed by a circuit in which L, C and a resistor are combined, in this embodiment, the power distributor shown in FIG. And the outputs of the first and second matching devices 70a and 70b connected to the second and high-frequency power supplies 71a and 71b, respectively, to the coaxial cable and the coaxial cable T-type connectors 81a, 81b, 82a, 82b, 82c, 82
d, 83a to 83h, 16 coaxial cables 6
A distributor for distributing from 8a to 68p was used.

Next, using the surface treatment apparatus having the structure shown in FIG. 1 to FIG.
i) A method for forming an a-Si film for a solar cell will be described.

First, the pressure in the vacuum vessel 51 is maintained at the atmospheric pressure, and the first and second gate gate valves 64a, 64a,
64b is opened, and a substrate 61, for example, 0.3 cm in thickness, 100 cm × 1 is used by using a substrate loading / unloading system (not shown).
A 00 cm glass substrate is placed on the ground electrode 54. Then, the first and second substrate access gate valves 64 are provided.
a, 64b are closed and the first and second vacuum pumps 40 are closed.
a, 40b are operated, and the first and second exhaust pipes 59 are operated.
a. The atmosphere in the vacuum vessel 51 is exhausted through 59b and after the pressure reaches about 1 × 10 ⁻⁷ Torr,
The next discharge gas is introduced.

Next, a discharge gas, for example, a SiH ₄ gas is supplied from the discharge gas introduction pipe 58 through the gas blowing holes 57 at a flow rate of about 2,000 to 3,000 sccm.
The pressure is maintained at 0.05-0.5 Torr. Further, the temperature of the substrate 61 is maintained at, for example, 180 ° C. in the range of 80 ° C. to 350 ° C. using the relationship between the surface temperature of the substrate 61 and the output (power) of the power supply for the substrate heater, which is obtained in advance as data. I do. Subsequently, the frequency of the first and second high-frequency power supplies 71a and 71b is changed from 10 MHz to 300 MHz.
z, for example, the output frequencies of the first high-frequency power supply 71a and the second high-frequency power supply 71b are 60 MHz and 65 MHz,
Output power is supplied at 3 kW to 5 kW for both.

Then, the pair of non-ground electrodes 52,
Glow discharge plasma of SiH ₄ is generated between the ground electrodes 54. As a result, Si present in the plasma
Radicals such as H ₃ , SiH ₂ , SiH, and Si are diffused by a diffusion phenomenon, and are adsorbed and deposited on the surface of the substrate 61 to form an a-Si film.

In the above example, the pair of non-ground electrodes 5
2. The size of the ground electrode 54 is 1200 mm × 120 each.
0 mm × 100 mm, the material was stainless steel, and the interval was 50 mm.

Table 2 below shows an example of the results of the film forming test of Example 1 described above. Note that the substrate size is × 1000 mm × 10
The film thickness distribution was evaluated by measuring the film thickness at 20 points on the diagonal line of the substrate by a double monochromator method and an ellipsometry method.

[0074]

[Table 2]

In the first embodiment, the frequencies of the two independent high-frequency power supplies, that is, the first and second high-frequency power supplies 71a, 71a,
The frequency of 71b is 14 MHz and 16 MHz, respectively.
(Average value 15MHz), 30MHz and 33M
Hz (average value 31.5 MHz), 60 MHz
And 65 MHz (average value 62.5 MHz), 8
0 MHz and 90 MHz (average value 85 MHz)
Met. Thus, the first and second high frequency power supplies 71
a, 71b, first and second matching devices 70a, 70b, first and second power distributors 69a, 69b, coaxial cables 68a-68p, current introduction terminals 66a-66p, stranded coaxial cables 67a-67p, etc. Is 90 MHz to 30
Since it is sufficiently applicable to 0 MHz, it can be said that the a-Si film can be sufficiently applied at a frequency of 90 MHz to 300 MHz.

The above data, that is, Table 2 is shown in FIG.
As shown in (B), the conventional example was considered difficult 1
A power frequency of 15
MHz class, 31.5 MHz class, 62.5 MHz class, 85
It shows that remarkably good results can be obtained in both the MHz class.

Further, the structure of the surface treatment apparatus and the methodologies show that the first embodiment of the present invention is extremely effective as a technique for increasing the area of an a-Si film and a technique for increasing the power supply frequency. ing.

Note that the film forming conditions in the first embodiment are set as follows.
And the mixing ratio of the discharge gas, for example, SiH ₄And H₂Flow ratio,
Optimize pressure, substrate temperature, plasma generation power, etc.
Thus, not only a-Si but also microcrystalline Si and polycrystalline S
It is known that i can be formed into a film.

As a discharge gas, SiH ₄ , NH
_{3, N 2,} etc. etc. that it makes possible the film and the SiN _x film by using the,
Gas having an etching action, for example, SF ₆ , SiC
It is also known that a predetermined etching process can be performed on the surface of a substrate by using an etching gas such as l ₄ , CF _4, and NF ₃ .

(Embodiment 2) Next, FIG. 9, FIG.
A device and a method according to a second embodiment will be described with reference to FIG. First, the configuration of the device will be described. However, the same members as those in FIGS. 1 to 8 are denoted by the same reference numerals, and description thereof will be omitted.

The configuration of the surface treatment apparatus shown in FIG. 9 is different from the first and second high-frequency power supplies 71a and 71b in FIG.
A sine wave signal having a frequency of 10 MHz to 300 MHz is oscillated at the output, and the phase of the two output signals is changed from 0 ° to 360 °.
2 consisting of a function generator, a phase shifter, and a high-frequency oscillator that can be changed every moment
The output phase variable oscillator 81, the first and second high-frequency signal transmission cables 82a and 82b, and the first and second high-frequency power amplifiers 83a and 83b are used, and all other device components are the same. Therefore, the other components of the apparatus will be described with reference to FIG.

Next, a method of forming an a-Si film for an amorphous silicon (a-Si) solar cell using the surface treatment apparatus having the structure shown in FIG. 9 will be described. First, the pressure in the vacuum vessel 51 is kept at the atmosphere, and the first and second pressures are maintained.
The gate valves 64a, 64b for opening and closing the substrate are opened, and a substrate loading / unloading system (not shown) is used.
For example, a glass substrate having a thickness of 0.3 cm and a size of 100 cm × 100 cm is placed on the ground electrode 54. Then, the first
And the second substrate inlet / outlet gate valves 64a, 64b are closed, the first and second vacuum pumps 60a, 60b are operated, and the above-mentioned vacuum container is passed through the first and second exhaust pipes 59a, 59b. The atmosphere in the chamber 51 is exhausted and the pressure is reduced to about 1
After reaching 10 ^-7 Torr, the next discharge gas is introduced.

Next, a discharge gas, for example, SiH4 gas is supplied at a flow rate of about 2000 to 3000 sccm from the discharge gas introduction pipe 58 through the gas blowing hole 57, and the pressure is maintained at 0.05 to 0.5 Torr. I do. Here, the surface temperature of the substrate 61 and the output (power) of the power supply for the substrate heater, the temperature of the substrate 61 being obtained in advance as data.
Is used in the range of 80 ° C. to 350 ° C., for example, 18
Keep at 0 ° C. Subsequently, the two-output variable phase oscillator 81
Is transmitted from the first high-frequency signal cable 82a to the first high-frequency power amplifier 83a, and the second output of the two-output phase-variable oscillator 81 is transmitted to the second high-frequency signal cable 82b through the second high-frequency signal cable 82b. The signal is transmitted to the power amplifier 83b.

In this case, the two-output phase variable oscillator 81
10A and 10B show the phases of the first and second outputs of FIG.
The phase difference θ between two sine wave signals shown as the phase θ is, for example, θ = 0 (fixed), or FIG.
As shown in (A) and (B), for example, a period is changed from several seconds to several hundredths of a second so as to change momentarily with a sawtooth wave in a range of ± 45 ° and ± 90 °. In addition,
The vertical axis of FIG. 10A is the first of the two-output phase variable oscillator 81.
10B, and the vertical axis in FIG. 10B indicates the first output voltage of the two-output phase variable oscillator 81.

The output frequency of the two-output phase variable oscillator 81 is 10 MHz to 300 MHz.
MHz. The power is supplied at 3 kW to 5 kW. Then, a pair of the non-ground electrode 52 and the ground electrode 54
During that time, a SiH ₄ glow discharge plasma is generated. As a result, SiH ₃ , SiH ₂ ,
Radicals such as SiH and Si are diffused by a diffusion phenomenon, and are adsorbed and deposited on the surface of the substrate 61 to form a-Si.
A film is formed.

In the above example, the size of the pair of ungrounded electrodes 52 and grounded electrodes 54 is 1200 mm × 1200 mm, respectively.
× 100 mm, each made of stainless steel, and the interval was 50 mm.

An example of the results of the film forming test of Example 2 is shown in Table 3 below. The substrate size is 1000 mm × 10
The film thickness distribution was evaluated by measuring the film thickness at 20 points on the diagonal line of the substrate by a double monochromator method and an ellipsometry method.

[0088]

[Table 3]

The data in Table 3 shows that when θ = 0 ° (fixed), a standing wave is generated between a pair of electrodes, and the film thickness distribution is extremely poor. However, when θ = ± 180 ° and θ = ± 360 °, No standing wave is generated, and it shows that the film thickness distribution is good particularly under the condition of θ = ± 360 °.

In the second embodiment, the two-output phase-variable oscillator 8
The output frequency of 1 is 60 MHz, and when the phase difference θ between the two output signals is fixed to θ = 0 °, θ = ± 180 °, and is temporally changed by a sawtooth wave having a period of 1/100 second. In this case, and when θ = ± 360 ° and the time is changed with a sawtooth wave of 1/100 second in one cycle, the first and second high-frequency power amplifiers 83a, 83b, Second
Matching units 70a and 70b, and the first and second power distributors 6
9a, 69b, coaxial cables 68a-68p, current introduction terminals 66a-66p, stranded coaxial cables 67a-6
Since 7p and the like can be sufficiently applied to 60 MHz to 300 MHz, the a-Si film can be formed at 60 MHz to 300 MHz.
It can be said that the frequency is sufficiently applicable.

The above data, that is, Table 3 is shown in FIG.
As shown in (B), the conventional example was considered difficult 1
For a super large area substrate of mx 1m, the power frequency 60
It shows that significantly better results are obtained at MHz.

The structure of the surface treatment apparatus and the methodologies also show that the second embodiment of the present invention is extremely effective as a technique for increasing the area of an a-Si film and a technique for increasing the power supply frequency. ing.

The film formation conditions in the second embodiment were optimized by adjusting the mixing ratio of the discharge gas, for example, the flow ratio of SiH ₄ and H ₂ , the pressure, the substrate temperature, the plasma generation power, etc. Not microcrystalline Si and polycrystalline Si
It is known that can be formed into a film.

Further, as a discharge gas, SiH₄, NH
₃, N₂And the like, the SiNx film can be formed.
Gas having a switching action, for example SF₆, SiCl₄,
CF ₄And NF₃If an etching gas such as
It is also known that a predetermined etching process can be performed on a surface.
You.

[0095]

As described above, according to the surface treatment apparatus of the first aspect, the power supply point is provided on the side surface of the electrode, so that the VHF band (30 MHz to 30 MHz) which has been considered difficult in the past.
The spatial distribution of high-density plasma using a power supply of 300 MHz) can be made uniform, and a uniform surface treatment of the substrate, that is, an improvement in film formation rate and etching rate and an improvement in uniformity can be achieved. This effect contributes significantly to the improvement of productivity not only in the industries of photoconductors for LSIs, LCDs and copiers, but also in the solar cell industry.

According to the surface treatment apparatus of the second aspect, since a plurality of power supply locations are set on the side surfaces of the electrodes, 13.sup.2 is used for a 1m.times.1m-class ultra-large area substrate which has been regarded as difficult in the past.
56 MHz class and VHF band (30 MHz to 300 MH
The spatial distribution of high-density plasma using the power supply of z) can be made uniform, and uniform surface treatment on an ultra large area substrate, that is, an improvement in film formation rate and etching rate and an improvement in uniformity can be achieved. This effect is especially true for solar cells and LCDs.
The degree of contribution to reducing product costs based on the improvement in productivity in the industry is extremely large.

According to the surface treatment apparatus of the third aspect, the high-frequency power whose phase changes momentarily from one another is supplied to the plurality of power supply points provided on the two opposing side surfaces of the rectangular non-grounded electrode. Therefore, the spatial distribution of plasma generated in the pair of electrodes can be averaged and uniformed in time and space. This enables uniform surface treatment of an ultra-large area substrate of 1 m × 1 m class or more, as in the case of the above-mentioned claim 2, and in particular, product cost based on the improvement of productivity in the solar cell and LCD industries. The contribution to the reduction of the amount is remarkably large.

Claim 4 has high value as a reliable means for realizing Claims 1 to 3.

Claim 5 is intended to expand the application range of the device according to claims 1 to 4, ie, to improve the film forming speed and the etching speed, and to realize a large area of the substrate. Remarkably large.

According to the sixth aspect, in addition to the effects of the first to fifth aspects, since a plurality of high-frequency power supplies, a plurality of matching devices, a plurality of power distributors, and a plurality of coaxial cables are combined, the power is reduced. There is an effect that the configuration of the supply system is simple and the cost is extremely low.

According to the seventh aspect, the productivity and quality and performance of thin-film semiconductor products such as LCDs, photoconductors for copying machines, solar cells, and LSIs are improved, and the cost performance is significantly increased.

Claim 8 provides a so-called large-area screen in which the product value increases as the product size increases. The effect of creating an applied product such as an LCD, a photoconductor for a copying machine, and a solar cell is created. Is extremely valuable.

According to the surface treatment method of claims 9 to 15,
In the conventional method, the power supply point, which is provided on the rear surface of the electrode, that is, the surface furthest from the space for generating plasma, is provided on the side surface closest to the plasma generation space. The spatial distribution of the high-density plasma using the power source can be made uniform, and the surface treatment of the substrate can be made uniform, that is, the film formation rate and the etching rate can be improved and the uniformity can be improved.

In addition, a 13.56 MHz class and a VHF class are used for a 1m × 1m class super large area substrate which has been regarded as difficult.
The spatial distribution of high-density plasma using a power source of a band (30 MHz to 300 MHz) can be made uniform, and uniform surface treatment on an ultra large area substrate, that is, film forming speed and etching speed can be improved and uniformity can be improved.

Further, a high frequency (HF band) and a VHF band (3
A plasma phenomenon using a frequency of 0 MHz to 300 MHz), that is, a merit of high density plasma, and a method of performing a uniform surface treatment can be realized.

The effects described above have a very large contribution to productivity improvement based on the productivity improvement in the solar cell and LCD industries in particular. In the fields of LSIs, photoconductors for copying machines, etc., the contribution to the improvement of productivity is remarkably large.

Further, the productivity, quality and performance of thin-film semiconductor products such as LCDs, photoconductors for copiers, solar cells, and LSIs are improved, resulting in a remarkable increase in cost performance.

[0108] The so-called large-area screen method in which the product value increases as the size of the product increases, can be provided to the manufacture of applied products such as LCDs, photoconductors for copiers, and solar cells. Occurs. Therefore, the industrial value in this field is extremely large.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an entire surface treatment apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a connection state between a coaxial cable around a vacuum vessel, a current introduction terminal, and the like in the surface treatment apparatus of FIG. 1;

FIG. 3 is an explanatory view showing a connection state between an ungrounded electrode and a stranded coaxial cable or the like in the surface treatment apparatus of FIG. 1;

FIG. 4 is an explanatory view of an ungrounded electrode, which is one configuration of the surface treatment apparatus of FIG. 1, a stranded coaxial cable connected thereto, and the like.

FIG. 5 is a diagram showing first and second configurations of the surface treatment apparatus of FIG. 1;
FIG. 5 is a partially cut-away perspective view for explaining details of a connection state between a core wire of a stranded wire type coaxial cable and an ungrounded electrode.

FIG. 6 is a cross-sectional view for explaining details of a connection state between a core wire of a first stranded coaxial cable, which is one configuration of the surface treatment apparatus of FIG. 1, and an ungrounded electrode.

FIG. 7 is a perspective view of a first stranded wire type coaxial cable, which is one configuration of the surface treatment device of FIG. 1;

FIG. 8 is an explanatory diagram of a power distributor, which is one configuration of the surface treatment apparatus of FIG. 1;

FIG. 9 is an explanatory view showing the entire surface treatment apparatus according to Embodiment 2 of the present invention.

FIG. 10 is a characteristic diagram showing a relationship between an output voltage and time at a phase difference of 0 in the two-output phase variable oscillator which is one configuration of the surface treatment apparatus of FIG. 9;

FIG. 11 is a characteristic diagram showing a relationship between an output voltage and time when a phase difference changes every moment in a two-output phase variable oscillator which is one configuration of the surface treatment apparatus of FIG. 9;

FIG. 12 is a diagram showing a film thickness (relative value) of amorphous silicon and a film thickness distribution in a horizontal direction and a vertical direction of an ungrounded electrode in the surface treatment apparatus of the present invention.

FIG. 13 is a view for explaining the flow of a high-frequency current output from a high-frequency power supply by a conventional surface treatment apparatus.

FIG. 14 is an explanatory diagram showing a potential distribution in a plasma space by a conventional surface treatment apparatus.

FIG. 15 is a diagram for explaining a flow of a high-frequency current output from a high-frequency power supply by the surface treatment apparatus of the present invention.

FIG. 16 is an explanatory diagram showing a potential distribution in a plasma space by the surface treatment apparatus of the present invention.

FIG. 17 is a diagram for explaining a flow of a high-frequency current output from a high-frequency power supply by another surface treatment apparatus of the present invention.

18 is a diagram illustrating the surface treatment apparatus of FIG. 9 in which the phase of the two-output phase variable high-frequency oscillator changes momentarily from one another.
Of standing wave when two powers are supplied to ungrounded electrode

FIG. 19 is a diagram illustrating the surface treatment apparatus of FIG. 9 in which the phase difference between the two high-frequency powers from the two-output phase variable high-frequency oscillator is 0.
FIG. 3 is an explanatory diagram of a standing wave when the angle is set to °.

FIG. 20 shows a substrate (area: 50) formed by a conventional surface treatment apparatus.
FIG. 4 is a characteristic diagram showing a relationship between a film thickness distribution (cm × 50 cm class) and a power supply frequency.

FIG. 21 shows a substrate (area: 10) formed by a conventional surface treatment apparatus.
FIG. 4 is a characteristic diagram showing a relationship between a film thickness distribution (0 cm × 100 cm class) and a power supply frequency.

FIG. 22 is an explanatory view of a conventional surface treatment apparatus.

FIG. 23 is an explanatory view of another conventional surface treatment apparatus.

FIG. 24 is an explanatory diagram of a power distributor which is one configuration of the surface treatment apparatus of FIG. 23.

FIG. 25 is an explanatory view of still another conventional surface treatment apparatus.

FIG. 26 is an explanatory diagram of a power supply location formed on a non-grounded electrode in the surface treatment apparatus of FIG. 25.

[Explanation of symbols]

 36: stranded wire (core wire), 37, 55a, 55b, 55c: insulator, 38: outer conductor, 51: vacuum vessel, 52: non-ground electrode, 53: substrate heater, 54: ground electrode, 56: space, 57 ... gas blowing holes, 58 ... discharge gas introduction pipes, 59a, 59b ... exhaust pipes, 60a, 60b ... vacuum pumps, 62 ... substrate heater power supplies, 64a, 64b ... gate valves, 65a-65p ... power supply points, 66a -66p ... current introduction terminal, 67a-67p ... stranded wire type coaxial cable, 68a-68p ... coaxial cable, 69a, 69b ... power distributor, 70a, 70b ... matching device, 71a, 71b ... high frequency power supply, 81 ... 2 output phase Variable oscillators, 82a, 82b: High-frequency signal transmission cables, 83a, 83b: High-frequency power amplifiers.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 14, 2000 (2000.8.1)
4)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 23

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01L 21/3065 H01L 21/31 C 21/31 H05H 1/46 MH05H 1/46 H01L 21/302 C ( 72) Inventor Hiroshi Majima 5-717-1, Fukahori-cho, Nagasaki City, Nagasaki Prefecture Inside the Nagasaki Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Tatsufumi Aoi 1-1-1, Akunouracho, Nagasaki City, Nagasaki Prefecture F-term in shipyard (reference) 2H088 FA19 FA30 HA01 HA08 MA20 2H090 JB02 JB04 JC07 JC09 LA04 4K030 AA06 BA30 BB03 BB04 EA04 EA11 FA01 KA15 KA17 KA18 KA24 KA30 LA16 5F004 AA00 BA04 DA03 AD03 DA03 AD03 CA13 EH01 EH13 EH19

Claims (15)

[Claims] 1. A vacuum vessel provided with an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and a substrate facing the substrate in the vacuum vessel. And a power supply system for supplying high-frequency power to the electrodes to discharge a discharge gas to generate plasma, and to use the generated plasma for a substrate disposed in a vacuum vessel. In a surface treatment apparatus for treating a surface, a power supply point to the electrode by the power supply system is a first surface in contact with a space in which plasma is generated, of the entire surface of the electrode, and the first surface A surface treatment apparatus, which is located on a side surface of a boundary with a second surface, which is a back side of the surface treatment device. 2. A vacuum vessel having an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and a substrate facing the substrate in the vacuum vessel. Electrode, a first ultra-high frequency power supply and a second ultra-high frequency power supply independent of the ultra-high frequency power supply, supplying high-frequency power to the electrode to discharge a discharge gas to generate plasma. A power supply system for generating, and a surface processing apparatus for processing the surface of a substrate disposed in a vacuum vessel using generated plasma, wherein the electrode has a square shape, one of the electrodes A plurality of first power supply terminals connected to an output circuit of the first ultrahigh frequency power supply are attached one by one to the first side surface, which is a side surface, at equal pitch intervals, and the first side surface is attached to the first side surface. Equal pitch on the second side, which is the opposite side A plurality of second power supply terminals connected to an output circuit of the second ultra-high frequency power supply, the ultra-high frequency power having substantially the same frequency as the output frequency of the first ultra-high frequency power supply. A surface treatment apparatus characterized by being attached to each other. 3. A vacuum vessel provided with an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and a predetermined position in the vacuum vessel. An electrode and a high-frequency power supply that changes the phase difference between the two outputs and the high-frequency power of the two outputs temporally in a sawtooth manner. The high-frequency power is supplied to the electrode to discharge a discharge gas and generate plasma. A power supply system for generating, and a surface processing apparatus for processing the surface of the substrate using the generated plasma, wherein the electrode has a rectangular shape, a first side that is one side surface of the electrode A plurality of power supply points connected to the output circuit of the high-frequency power supply are arranged at equal pitches on one side and a second side opposite to the first side.
A surface treatment device characterized by being attached one by one. 4. The surface treatment apparatus according to claim 1, wherein a coaxial cable is used to supply power to a power supply point of the electrode by the power supply system. 5. The frequency of the high-frequency power is 10 MHz.
The surface treatment apparatus according to any one of claims 1 to 3, wherein the surface treatment apparatus belongs to an HF band to a VHF band of 300 MHz to 300 MHz. 6. The power supply system includes at least one high-frequency power supply for generating high-frequency power, and at least one power supply for branching an output of the high-frequency power supply into a number corresponding to the number of the plurality of power supply points. A distributor, at least one matching device arranged via a high-frequency power transmission coaxial cable between the high-frequency power source and at least one power distributor, and the high-frequency power branched by the power distributor. The surface treatment apparatus according to claim 2, comprising a plurality of stranded coaxial cables leading to each of the power supply points. 7. An amorphous Si-based thin film on the substrate surface.
The surface treatment apparatus according to claim 1, wherein one of a microcrystalline Si-based thin film and a polycrystalline Si-based thin film is formed. 8. The substrate according to claim 1, wherein the electrode has a rectangular shape, and the substrate processed using plasma is a substrate for a solar cell, a liquid crystal display, or a large-scale integrated circuit. The surface treatment apparatus according to claim 1. 9. A vacuum vessel provided with an exhaust system, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, an electrode arranged at a predetermined position in the vacuum vessel, and a high frequency power And a power supply system that supplies a discharge gas to generate a plasma by discharging the discharge gas, and a surface processing method of processing the surface of the substrate using the generated plasma. A surface treatment method, wherein power is supplied to the power supply location using the power supply system. 10. A vacuum vessel provided with an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and a predetermined position in the vacuum vessel. An electrode and at least two first and second ultrahigh-frequency power supplies for generating high-frequency power independent of each other; supplying power to the electrodes to supply high-frequency power to discharge a discharge gas to generate plasma. A surface treatment method for treating the surface of a substrate using generated plasma by using a surface treatment apparatus provided with a system, wherein the shape of the electrode is square, and the first is one side surface of the electrode. A first plurality of power supply ends are attached to the side surface at equal pitch intervals, and a second plurality of power supply ends are attached to the second side surface opposite to the first side surface at equal pitch intervals, Output of the first ultrahigh frequency power supply And the first plurality of power supply terminals are connected one by one with a coaxial cable, and the output circuit of the second ultra-high frequency power supply and the second plurality of power supply terminals are connected one by one with a coaxial cable. A surface treatment method characterized by connecting. 11. A vacuum vessel provided with an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and a predetermined position in the vacuum vessel. An electrode and a high-frequency power supply that changes the phase difference between the two outputs and the high-frequency power of the two outputs temporally in a sawtooth manner;
Surface treatment for treating the surface of the substrate using the generated plasma, using a surface treatment apparatus having a power supply system for supplying high-frequency power to the electrode to discharge a discharge gas and generate plasma. A method, wherein the shape of the electrode is square, and a first plurality of power supply terminals are attached at equal pitch intervals to a first side surface, which is one side surface of the electrode, and the other side facing the first side surface is provided. A second plurality of power supply terminals are attached at equal pitch intervals to a second side surface, which is a side surface of the ultra-high frequency power supply, and a first output circuit and a second output circuit of the ultrahigh frequency power supply are respectively connected to the first and second plurality of power sources. A surface treatment method characterized in that the power supply terminals are connected one by one by a coaxial cable. 12. An ultra-high frequency power supply which oscillates from 10 MHz to 300 MHz and supplies required power as said high frequency power supply, and uses at least one matching unit and a plurality of coaxial cables to control said ultra high frequency power supply from 10 MHz to 300 M
The surface treatment method according to any one of claims 9 to 11, wherein an output power of Hz is supplied to a power supply location. 13. A method according to claim 9, wherein at least a monosilane gas is used as a discharge gas to form any one of an amorphous Si-based thin film, a microcrystalline Si-based thin film, and a polycrystalline Si-based thin film. The surface treatment method according to any one of the above. 14. A substrate according to claim 9, wherein a large area substrate having an area of 50 cm × 50 cm is used as the substrate, and the surface treatment is performed at a substrate temperature of 80 ° C. to 350 ° C. Or the surface treatment method described. 15. A vacuum vessel provided with an exhaust system in which a substrate is set, a discharge gas introduction system for introducing a discharge gas into the vacuum vessel, and a predetermined position in the vacuum vessel. An electrode and a high-frequency power supply that changes the phase difference between the two outputs and the high-frequency power of the two outputs temporally in a sawtooth manner;
A surface treatment method for treating the surface of a substrate using generated plasma by using a surface treatment apparatus having a power supply system that supplies high-frequency power to the electrode to discharge a discharge gas to generate plasma. The electrode has a rectangular shape, and is connected to the power supply system at a first side surface, which is one of four side surfaces of the electrode, and at a second side surface opposite to the first side surface. A plurality of power supply points, and a first output and a second output of the high-frequency power supply are respectively connected to the power supply points provided on the first side and the second side. A surface treatment method characterized by supplying two electric powers that change from moment to moment.