JP4180333B2 - Plasma CVD apparatus and plasma CVD method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma CVD apparatus and a plasma CVD method for forming a thin film on an object to be deposited using plasma as a surface treatment method.
[0002]
[Prior art]
FIG. 2 is a configuration diagram showing a conventional plasma CVD (Chemical Vapor Deposition) apparatus. This CVD apparatus is a general high-frequency parallel plate type RF-excited plasma CVD apparatus.
[0003]
The plasma CVD apparatus has a vacuum chamber 101, and in this vacuum chamber 101, a flat cathode electrode 102 connected to a high frequency power source (RF power source) 106 and a grounded flat plate anode electrode (earth counter electrode) 103 are arranged in parallel. It is a device facing each other. The flat cathode electrode 102 is configured to place a substrate 104 which is a film formation target (for example, a Si wafer or a SUS plate). This plasma CVD apparatus incorporates a vacuum exhaust system and a gas introduction system, and the grounded counter electrode 103, which is grounded, serves as a gas shower electrode in which numerous holes are distributed in a shower shape on the surface and introduces a source gas. In some cases. The flat cathode electrode 102 and the high frequency power source are connected via a matching box (MB) 107.
[0004]
A source gas introduction mechanism that introduces a source gas into the chamber 101 is connected to the vacuum chamber 101. The source gas introduction mechanism has a pipe for introducing a source gas into the vacuum chamber 101, and a mass flow controller (MFC) 109 is connected to the pipe via a vacuum valve 108. The mass flow controller 109 is connected to a source gas generation source via a vacuum valve 108.
[0005]
For example, when a DLC (Diamond Like Carbon) film is formed using this apparatus, the following procedure is followed.
First, the substrate 104 is fixed on the flat cathode electrode 102. Next, the vacuum chamber 101 is evacuated to reach a predetermined degree of vacuum. Next, a source gas is supplied into the vacuum chamber 101. In the case of DLC film formation, a hydrocarbon-based gas is used. Next, a high frequency output is applied to the flat cathode electrode 102 via the matching box 107 by the high frequency power source 106. As a result, plasma 105 due to the source gas is generated between the ground counter electrode 103 and the flat cathode electrode 102, and a DLC film is deposited on the substrate 104 on the flat cathode electrode. Next, after film formation for a predetermined time, the high-frequency output is turned off and the gas supply is stopped. Next, evacuation is stopped, the chamber 101 is opened to the atmosphere, and the substrate 104 is taken out.
[0006]
[Problems to be solved by the invention]
By the way, in the conventional high-frequency parallel plate plasma CVD apparatus, since the surface of the substrate 104 is exposed to the plasma 105, there is a problem that plasma damage to the substrate surface due to electrons and ions in the plasma is large. However, it has been thought that this plasma damage exerts a bombarding effect on the substrate surface and contributes to an improvement in the adhesion of the film formed on the substrate surface.
[0007]
However, such a parallel plate plasma CVD apparatus is not suitable for film formation on an object to be formed which is easily damaged by heat due to plasma or damage by accelerated ions. For example, it is not suitable for forming a film on a polymer base material (for example, a polymer film) that is weak against heat, such as plastic or an organic EL element. Therefore, it is almost impossible to form a useful film on a polymer base material with a conventional plasma CVD apparatus.
[0008]
The present invention has been made in view of the above circumstances, and its purpose is to reduce plasma damage to the deposition target object by preventing exposure of the plasma to the deposition target object. Another object of the present invention is to provide a plasma CVD apparatus and a plasma CVD method.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, a plasma CVD apparatus according to the present invention is a plasma CVD apparatus that forms a thin film on an object to be formed using plasma, and is disposed in the chamber and in the chamber. A holder for holding a film object, a counter electrode disposed in the chamber and facing the surface opposite to the surface of the holder for holding the film formation object, and a source gas in the chamber A raw material gas supply means, an output supply means for supplying output into the chamber, and an exhaust means for exhausting the chamber, and plasma is generated between the holder and the counter electrode to form a thin film It is characterized by forming a film.
[0010]
According to the plasma CVD apparatus, the counter electrode is disposed so as to face the surface of the holder opposite to the surface on which the deposition target is held. Therefore, plasma can be generated between the counter electrode and the holder without generating plasma near the surface of the deposition target. Various activated ions and neutral active species exist in the chamber at this time, but these various ions and neutral active species are not localized only in the plasma, and the film is formed. It is also present near the surface of the object. Therefore, a thin film can be formed on the deposition target. Thus, since a thin film is formed on the surface of the film formation target without generating plasma near the surface of the film formation target, the film formation target can be prevented from being exposed to plasma, Plasma damage to the deposition target can be reduced.
[0011]
In the plasma CVD apparatus according to the present invention, the output supply means may use a high-frequency power source.
In the plasma CVD apparatus according to the present invention, the thin film can be an amorphous carbon-based film.
[0012]
A plasma CVD method according to the present invention is a method for forming a thin film on an object to be deposited using the plasma CVD apparatus according to any one of claims 1 to 3, wherein the film is deposited on a holder. Holding the object, evacuating the chamber, introducing a source gas into the chamber, applying an output to the holder and generating plasma between the holder and the counter electrode, The method is characterized in that a thin film is formed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram schematically showing a plasma CVD apparatus according to an embodiment of the present invention.
[0014]
The plasma CVD apparatus has a vacuum chamber 1. The vacuum chamber 1 is connected to a source gas introduction mechanism that introduces a source gas into the chamber 1. The vacuum chamber 1 is connected to an evacuation mechanism that evacuates the chamber 1.
[0015]
A substrate holder 2 for holding a substrate 4 as a film formation target is disposed in the vacuum chamber 1, and the substrate holder 2 holds the substrate 4 downward. The substrate holder 2 is connected to an RF application site 6, and this RF application site 6 is connected to an output supply mechanism that supplies a high frequency output (RF output).
[0016]
Above the substrate holder 2, a ground counter electrode 3 is disposed so as to face the substrate holder. The earth counter electrode 3 has a bowl-like shape (a concave cross section), and is configured such that plasma light 5 is generated by a source gas between the substrate holder 2 and the earth counter electrode 3. In addition, although the preferable shape of the earth | ground opposing electrode 3 is a cross-sectional concave shape, it is not limited to this shape, It can also be set as another shape.
[0017]
The source gas introduction mechanism has a pipe for introducing the source gas into the vacuum chamber 1. A mass flow controller (MFC) 9 is connected to this pipe via a vacuum valve 8. The mass flow controller 9 is connected to a source gas generation source through a vacuum valve 8 and a filter. The source gas generation source differs in the type of source gas generated depending on the thin film to be formed. For example, when a DLC film is formed, a hydrocarbon gas or the like is generated.
[0018]
The output supply mechanism supplies an RF output to the vacuum chamber 1 and includes an impedance matching unit (MB; matching box) 7 and a high-frequency power source 10. That is, the vacuum chamber 1 is connected to the matching box 7, and the matching box 7 is connected to the high frequency power supply 10 through the coaxial cable.
[0019]
The evacuation mechanism evacuates the vacuum chamber 1. The vacuum chamber 1 is provided with an exhaust port for exhausting the inside of the chamber. The exhaust port is connected to a vacuum valve and a leak valve for opening to the atmosphere via piping. The vacuum valve is connected to a vacuum pump via a pipe.
[0020]
Next, a method for forming a DLC film on the substrate 4 using the plasma CVD apparatus will be described. The DLC film is an amorphous carbon-based thin film containing carbon as a main component, and includes various hard carbon films.
[0021]
First, a substrate as a film formation target is held by the substrate holder 2, and the substrate holder 2 is accommodated in the vacuum chamber 1. Next, the leak valve is closed, the vacuum valve is opened, and the vacuum pump is operated. Thereby, the inside of the vacuum chamber 1 is evacuated through the exhaust port and the piping. Then, it is confirmed that the inside of the vacuum chamber 1 has reached a predetermined pressure.
[0022]
Next, the vacuum valve is opened, a raw material gas (for example, hydrocarbon gas) is generated in the raw material gas generation source, this hydrocarbon gas is introduced into the pipe through the filter and the vacuum valve 8, and the flow rate is controlled by the mass flow controller 9. Hydrogen gas is introduced into the vacuum chamber 1. And the pressure suitable for film-forming of a DLC thin film is maintained by the balance of the controlled gas flow rate and exhaust capability.
[0023]
Thereafter, an RF output of 13.56 MHz, for example, is supplied from the high frequency power supply 10 to the substrate holder 2 via the RF application site 6 and the matching box 7. Thereby, plasma is ignited between the substrate holder 2 and the ground counter electrode 3. At this time, the matching box 7 is matched with the impedance of the substrate holder 2 and the ground counter electrode 3 by the inductance L and the capacitance C. As a result, hydrocarbon-based plasma light 5 is generated between the substrate holder 2 and the ground counter electrode 3, and a DLC film is formed on the substrate 4. At this time, no plasma light is generated near the substrate surface, but a DLC film is firmly formed on the substrate surface. The formed DLC film was a good film that was not damaged even when rubbed with the tip of a driver.
[0024]
According to the embodiment, the ground counter electrode 3 is arranged so as to face the surface opposite to the surface of the substrate holder 2 on which the substrate is held. Therefore, plasma light 5 can be generated between the ground counter electrode 3 and the substrate holder 2 without generating plasma light near the surface of the substrate 4. In this case, activated various ions and neutral active species exist in the vacuum chamber 1 during discharge, but these various ions and neutral active species are localized only in the plasma light 5. It also exists near the surface of the substrate 4. Therefore, a DLC film can be formed on the surface of the substrate 4. Thus, since the DLC film is formed on the substrate surface without generating plasma light on the substrate surface, the substrate surface can be prevented from being exposed to plasma, and plasma damage to the substrate surface can be reduced. . Therefore, it is possible to form a DLC film on an object to be deposited (a polymer material such as plastic or organic EL) that is easily damaged by plasma.
[0025]
Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the shape of the substrate holder 2, the material of the substrate 4, the shape of the ground counter electrode 3, and the like can be variously changed.
[0026]
In the above embodiment, the DLC film is formed on the substrate 4, but a thin film of another material can be formed on the substrate. In this case, a source gas generation source other than the hydrocarbon gas generation source is used.
[0027]
In the above embodiment, a ground potential is applied to the ground counter electrode 3 and an RF output is applied to the substrate holder to generate plasma. However, another output is applied to the ground counter electrode or the substrate holder. It is also possible to generate plasma.
[0028]
【The invention's effect】
As described above, according to the present invention, the counter electrode is disposed so as to face the surface of the holder opposite to the surface on which the deposition target is held. Therefore, it is possible to prevent the plasma exposure to the film formation target, thereby providing a plasma CVD apparatus and a plasma CVD method in which plasma damage to the film formation target is reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram schematically showing a plasma CVD apparatus according to an embodiment of the present invention.
FIG. 2 is a configuration diagram showing a conventional plasma CVD apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,101 ... Vacuum chamber 2 ... Substrate holder 3 ... Earth counter electrode 4, 104 ... Substrate 5, 105 ... Plasma light 6 ... RF application site 7, 107 ... Matching box (MB)
8, 108 ... Vacuum valve 9, 109 ... Mass flow controller (MFC)
DESCRIPTION OF SYMBOLS 10,106 ... High frequency power supply 102 ... Flat cathode electrode 103 ... Flat plate anode electrode (grounding counter electrode)

Claims (4)

A plasma CVD apparatus for forming a thin film on an object to be deposited using plasma,
A chamber;
A holder disposed in the chamber for holding an object to be deposited;
A counter electrode disposed in the chamber and disposed so as to face a surface opposite to a surface holding the film formation target of the holder;
Source gas supply means for supplying source gas into the chamber;
Output supply means for supplying output into the chamber;
Exhaust means for exhausting the chamber;
Comprising
A plasma CVD apparatus, wherein a thin film is formed by generating plasma between a holder and a counter electrode. The plasma CVD apparatus according to claim 1, wherein the output supply means uses a high frequency power source. The plasma CVD apparatus according to claim 1 or 2, wherein the thin film is an amorphous carbon-based film. A method for forming a thin film on an object to be formed using the plasma CVD apparatus according to any one of claims 1 to 3,
Hold the deposition target in the holder,
The chamber is evacuated,
Introduce source gas into the chamber,
A plasma CVD method characterized in that a thin film is formed on an object to be deposited by applying an output to a holder to generate plasma between the holder and the counter electrode.

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