WO2014103318A1

WO2014103318A1 - Method for forming protective film using plasma cvd method

Info

Publication number: WO2014103318A1
Application number: PCT/JP2013/007623
Authority: WO
Inventors: 玉垣　浩; 潤二芳賀; 弘高伊藤
Original assignee: 株式会社神戸製鋼所
Priority date: 2012-12-27
Filing date: 2013-12-26
Publication date: 2014-07-03
Also published as: JP2014125670A

Abstract

This method for forming a protective film using a plasma cvd method on the surfaces of a plurality of conductive substrates includes the following steps to be performed using a plasma CVD device (1) for implementing this method: a step for dividing the plurality of substrates into two groups, and mounting the substrates inside a vacuum chamber (2) in a state in which the first group and the other group and the chamber are electrically insulated; a step for creating a vacuum state in the interior of the vacuum chamber (2); and a step for forming a protective film on the surfaces of the substrates by supplying the interior of the vacuum chamber (2) with a processing gas containing a deposition gas, and generating a discharge plasma between the substrates by supplying AC power between the two groups of substrates.

Description

Method for forming protective film by plasma CVD method

The present invention relates to a method for forming a protective film by a plasma CVD method in which a CVD (Chemical Vapor Deposition) film is formed on a substrate. In particular, the present invention relates to a method for forming a protective film having high production efficiency and high adhesion to a base material while maintaining stable film formation conditions.

Automotive engine parts such as piston rings are required to have good wear resistance, heat resistance, and seizure resistance. Therefore, wear resistance coating such as DLC (Diamond-Like-Carbon) is applied to these mechanical parts using a plasma CVD method.

By the way, when performing the plasma CVD method on the above-described base material, it is preferable to perform processing at once by accommodating a large number of base materials in a vacuum chamber in consideration of productivity. Thus, when processing many base materials at once, the thickness and film quality of the film | membrane formed on each base material must be made uniform between base materials. Therefore, a conventional plasma CVD apparatus employs a method in which a film is formed in a state where the base materials are arranged on a table and the base materials are rotated and revolved.

For example, Patent Document 1 discloses a film forming apparatus having plasma generating means, multicusp magnetic field generating means, and holding and rotating means. The plasma generating means generates plasma in a vacuum chamber in which a base material to be deposited is disposed. The multicusp magnetic field generating means forms a multicusp magnetic field for confining the plasma generated by the plasma generating means in a confined space around the substrate. The holding and rotating means holds the substrate and rotates around the center of the confinement space as a central axis. In the film forming apparatus of Patent Document 1, all base materials are connected to one pole of a power source together with a table on which they are placed, a bias voltage is applied, and a ground potential to which the other pole of the power source is connected. Glow discharge is generated with the vacuum chamber in the counter electrode as a counter electrode, and plasma is generated. The source gas is decomposed by this plasma, and a film is formed on the surface of the substrate.

On the other hand, Patent Document 2 is a plasma CVD apparatus that forms a film on the surface of an object (base material) by plasma CVD, and includes a vacuum chamber, plasma generation means, reflection means, and source gas introduction means. A plasma CVD apparatus is disclosed. The object to be processed is arranged inside the vacuum chamber. The plasma generating means generates plasma in the vacuum chamber. The reflecting means is provided in the vacuum chamber so as to face the plasma generating means, and reflects the plasma toward the plasma generating means. The raw material gas introducing means introduces a raw material gas that becomes a material of the coating into the vacuum chamber. The portion of the reflecting means that reflects the plasma is formed of metal wool. In the plasma CVD apparatus described in Patent Document 2, the object to be processed is connected to a DC (Direct Current) power source and is applied with a bias voltage. The source gas is decomposed by the plasma generated in the center of the vacuum chamber using a plasma gun, and a film is formed while applying a bias voltage to the object to be processed surrounding the plasma.

However, when a hard protective film such as DLC is coated by the apparatus disclosed in Patent Document 1 and / or Patent Document 2, there is a limit to the film thickness that can be formed, or a protective film having a certain thickness. If the film is coated, the protective film may be peeled off. Alternatively, it is necessary to form an intermediate layer in order to ensure adhesion of the protective film.

JP 2007-308758 A JP 2006-169563 A

An object of the present invention is a method for forming a protective film by a plasma CVD method for forming a CVD film on a base material, which is difficult to deposit on a portion other than the base material, and can be stably operated without cleaning over a long period of time. An object of the present invention is to provide a method capable of forming a protective film that is capable of forming a protective film having high production efficiency and high adhesion to a substrate while maintaining stable film formation conditions.

The method for forming a protective film of the present invention is a method of forming a protective film on the surface of a plurality of conductive base materials by plasma CVD, wherein the plurality of base materials are divided into two groups, Mounting the substrate in the chamber in a state of being electrically insulated from the other group and the chamber; bringing the inside of the chamber into a vacuum; and supplying a process gas including a film forming gas to the chamber And forming a protective film on the surface of the substrate by generating discharge plasma between the substrates by supplying AC power between the two groups of substrates. Features.

1 is a perspective view showing an overall configuration of a plasma CVD apparatus that realizes a protective film forming method according to a first embodiment of the present invention. It is a top view of the plasma CVD apparatus shown in FIG. It is a figure which shows a sinusoidal waveform as an output waveform of the plasma generation power supply in the plasma CVD apparatus shown by FIG. It is a figure which shows a pulse-shaped waveform as an output waveform of the plasma generation power supply in the plasma CVD apparatus shown by FIG. It is a figure which shows the waveform which divided | segmented one pulse into the finer pulse as an output waveform of the plasma generation power supply in the plasma CVD apparatus shown by FIG. It is a figure which shows the example of installation of a piston ring as an example of installation of the base material to a rotation table. It is a figure which shows the example of installation of small members, such as a piston pin, as an example of installation of the base material to a rotation table. It is a figure showing the change of the electric potential during the film-forming by the alternating voltage in the plasma CVD apparatus shown by FIG. It is a figure showing the change of the electric potential during film-forming by the negative DC electric potential in the plasma CVD apparatus shown by FIG. 1 being intermittently added. It is a perspective view which shows the whole structure of the plasma CVD apparatus which implement | achieves the formation method of the protective film which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the whole structure of the plasma CVD apparatus which implement | achieves the formation method of the protective film which concerns on the 3rd Embodiment of this invention. It is a top view of the plasma CVD apparatus shown by FIG. It is a perspective view which shows the whole structure of the plasma CVD apparatus which implement | achieves the formation method of the protective film which concerns on the 4th Embodiment of this invention. It is a figure which shows the operating state of the plasma CVD apparatus which implement | achieves the formation method of the protective film which concerns on the 5th Embodiment of this invention. It is a figure which shows the operating state of the plasma CVD apparatus which implement | achieves the formation method of the protective film which concerns on the 6th Embodiment of this invention.

Hereinafter, an embodiment of a method for forming a protective film according to the present invention will be described in detail with reference to the drawings. In addition, suppose that the object on which this protective film is formed is a base material (reference numeral W (meaning work)).

<First Embodiment>
FIG. 1 shows a perspective view of the overall configuration of a plasma CVD apparatus 1 that realizes the method for forming a protective film according to the first embodiment of the present invention, and FIG. 2 shows a top view thereof.

The vacuum chamber 2 is a housing whose inside can be hermetically sealed from the outside. A vacuum pump 3 (vacuum evacuation means) is provided on the side of the vacuum chamber 2 to evacuate the gas in the vacuum chamber 2 to bring the inside of the vacuum chamber 2 into a low pressure state (vacuum state). By this vacuum pump 3, the inside of the vacuum chamber 2 can be depressurized to a vacuum state.

On the other hand, as shown in FIG. 2, in the vacuum chamber 2, a gas supply unit 9 for supplying a process gas including a source gas into the vacuum chamber 2 is provided. The gas supply unit 9 is configured to supply a predetermined amount of raw material gas necessary for forming the CVD film and assist gas for assisting film formation from the cylinder 16 into the vacuum chamber 2.

Specifically, as a process gas, when forming a carbon-based CVD film such as DLC (diamond-like carbon, amorphous carbon film), hydrocarbons (acetylene, ethylene, methane, ethane, benzene, Source gas containing toluene or the like, or a gas obtained by adding an inert gas (such as argon or helium) as an assist gas to the source gas. When a silicon compound CVD film (SiOx film, SiOC film, SiNx film, SiCN film) is formed, a silicon-based organic compound (monosilane, TMS (trimethylsilane), TEOS (tetraethoxysilane), HMDSO ( Hexamethyldisiloxane, etc.) or a raw material gas containing silicon such as silane can be used by adding a reactive gas such as oxygen, nitrogen, ammonia or the like and further adding an inert gas such as argon as an assist gas if necessary. In addition to the above-described CVD film, a TiOx film, an AlOx film, an AlN film, or the like can be formed as the CVD film.

It is also possible to mix a small amount of additive source gas with the main source gas. For example, when a DLC film is formed, a film containing Si in DLC can be formed by adding a small amount of a silicon-based organic compound gas using hydrocarbon as a main source gas. Alternatively, when a DLC film is formed, by adding a small amount of a raw material gas containing metal (for example, TTIP (titanium isopropoxide) or TDMAT (tetradimethylaminotitanium)) as a main raw material gas for hydrocarbons. A film containing a metal (titanium in the example) can be formed in DLC.

In addition, these source gas, reaction gas, and assist gas can be used combining suitably the kind of gas to be used.

Further, the plasma generation power source 10 provided in the plasma CVD apparatus 1 is used for generating a glow discharge in the process gas supplied in the vacuum chamber 2 to generate plasma, and supplying AC power. As the AC power supplied from the plasma generating power source 10, not only an AC whose current and voltage change positively and negatively according to a sine wave waveform, but also a rectangular wave AC that switches between positive and negative according to a pulsed waveform may be used. In addition, for this alternating current, a continuous pulse group having the same polarity or an alternating sine wave alternating with a rectangular wave can be used. The voltage waveform during actual plasma generation may be distorted due to the influence of plasma generation. In addition, when plasma is generated, the zero level of the AC voltage shifts, and when the potential of each electrode is measured with respect to the ground potential, 80-95% of the applied voltage is applied to the negative electrode and 5% of the applied voltage is applied to the positive electrode. It is often observed that 20% is added. As described above, the plasma generating power source is preferably composed of one AC power source. However, it is also possible to realize a potential fluctuation equivalent to this by two power sources, and these are included in the scope of the present invention.

The alternating current supplied from the plasma generating power supply 10 preferably has a frequency in the range of 1 kHz to 1 MHz. This is because if the frequency is less than 1 kHz, the coating is likely to be charged up, and a mechanism for transmitting electric power having a frequency exceeding 1 MHz to the rotating and revolving substrate W is difficult. Furthermore, considering the availability of the power source, the range of 10 kHz to 400 kHz is more preferable. The AC voltage supplied from the plasma generating power supply 10 is preferably in the range of 300 to 3000 V required for maintaining glow discharge at a peak value. Further, the AC power supplied from the plasma generating power supply 10 varies depending on the surface area of the substrate W, but it is preferable that the power density per unit area is about 0.05 to 5 W / cm ² .

Here, as the AC power supply waveform supplied from the plasma generating power supply 10, a waveform measured between both poles of the power supply, and a sinusoidal waveform shown in FIG. 3A can be used. The waveform during actual operation is a waveform distorted by the influence of plasma generation. Due to the difference in mobility between electrons and ions in the plasma, the potential of each electrode with respect to the chamber is larger on the minus side and smaller on the plus side. Similarly, the pulsed voltage waveform shown in FIG. 3B can also be used as an AC power supply waveform supplied from the plasma generating power supply 10. This may also have a distorted waveform during actual operation.

Such a pulsed power supply can set the pulse width and its duty in addition to the high voltage, and is excellent in terms of plasma controllability. Further, as shown in FIG. 3C, the method of supplying one pulse divided into finer pulses is effective in suppressing abnormal discharge or the like, and therefore, as an AC power supply waveform supplied from the plasma generating power supply 10. preferable.

When an alternating current of such frequency, voltage, and power (power density) is applied between a pair of electrodes arranged in the vacuum chamber 2, a glow discharge is generated between the electrodes, and the generated glow discharge causes a vacuum chamber. The process gas supplied into 2 is decomposed to generate plasma. Then, these gas components decomposed by the plasma are deposited on the electrode surface, whereby a CVD film is formed. That is, if a base material is used for either of the pair of electrodes, a CVD film can be formed on the surface of the base material.

In the vacuum chamber 2, a heater for adjusting the film quality by controlling the temperature of the substrate may be provided as appropriate.

In this plasma CVD apparatus 1, a plurality of (six in this case) rotation tables 4 that hold a substrate W (for example, see FIGS. 4A and 4B) that is a film formation target in a rotating state are provided as one rotation table. 5 is provided. That is, the plurality of rotation tables 4 are provided on a rotation table 5, and the rotation table 5 provided with the plurality of rotation tables 4 in the plasma CVD apparatus 1 is used as a rotation axis (rotation axis P) of the rotation table 4. A rotation mechanism 8 that revolves around a revolution axis Q having parallel axes is provided. Each of the plurality of rotation tables 4 is arranged to have an equal radius from the revolution axis Q of the rotary table 5 and at equal intervals around the revolution axis Q.

The notations “A” and “B” in FIG. 1 are two groups in which a plurality of base materials are separated, and electrical insulation is provided between one group and the chamber potential and the other group. Above, it is connected to both electrodes of the plasma generating power source 10 for generating plasma. This will be described in more detail.

As shown in FIGS. 1 and 2, in this plasma CVD apparatus 1, half of the plurality of rotation tables 4 is a first group 18 connected to one pole of the plasma generation power source 10. In addition, the remaining half of the plurality of rotation tables 4 is a second group 19 connected to the other pole of the plasma generation power source 10. Plasma can be generated between the substrate W held on the rotation table 4 of the first group 18 and the substrate W held on the rotation table 4 of the second group 19 having different polarities.

Specifically, in a state where six rotation tables 4 are arranged in total on the rotary table 5, there are three rotation tables 4 in the first group 18 indicated by “A” in FIG. There are also a total of three rotation tables 4 of the second group 19 indicated by “B” in FIG. The number of rotation tables 4 belonging to the first group 18 is the same as the number of rotation tables 4 belonging to the second group 19.

The rotation table 4 of the second group 19 is provided on both sides of the rotation table 4 belonging to the first group 18 with respect to these rotation tables 4. A rotation table 4 belonging to another first group 18 is provided next to the rotation table 4 of the second group 19. That is, the rotation table 4 belonging to the first group 18 and the rotation table 4 belonging to the second group 19 are arranged so as to be alternately (alternately) arranged one by one around the revolution axis Q of the rotation table 5. Yes.

The three rotation tables 4 belonging to the first group 18 are all connected to one electrode 10a of the plasma generation power source 10. Further, all of the three rotation tables 4 belonging to the second group 19 are connected to the other electrode 10 b of the plasma generating power source 10. That is, during voltage application, the rotation table 4 belonging to the first group 18 and the rotation table 4 belonging to the second group 19 are always in opposite polarities.

In addition, in order to make each rotation table 4 have the above-described polarity, a brush mechanism (not shown) is provided on each of the revolution axis Q and the rotation axis P, and a voltage of each polarity may be applied through this brush mechanism. The revolution shaft Q and the rotation shaft P are held freely during rotation through a bearing mechanism, but a voltage may be applied through this bearing mechanism.

The base material W formed by the plasma CVD apparatus 1 is preferably provided as a base material set WS in a vertically long cylindrical space in order to enable uniform film formation.

For example, when the substrate W is a piston ring as shown in FIG. 4A, the film may be formed non-uniformly as it is. For this reason, what is necessary is just to form the base material set WS which accumulated the base material W, as FIG. 4A shows. In this case, when the base material set WS is formed by stacking the base materials W, when a part of the circumferential direction is missing and a complete cylinder is not obtained, the base with the cover 11 covered with the cover 11 as necessary. By forming the material set WS, uniform film formation is possible.

When the base material W to be formed is a small member (for example, a small piston pin) as shown in FIG. 4B, an installation jig 13 in which the disks 12 are stacked in multiple stages in the vertical direction is prepared. The base material W may be provided on the circular plate 12 as a base material set WS, and the base material set WS may be provided in a cylindrical space.

Furthermore, even if the base material W is a thing having a shape other than the above, a fixing jig may be appropriately manufactured so that the jig and the base material can be accommodated in the cylindrical space.

Next, a method for forming a protective film by plasma CVD using the plasma CVD apparatus 1 having the above-described configuration will be described.

(From substrate set to vacuum exhaust)
First, work sets are mounted on all the rotating shafts, and the substrate W is set. When the base material W is set in this way, the vacuum chamber 2 is evacuated to a high vacuum state using the vacuum pump 3 (evacuation means 3).

(Ion bombard treatment)
Next, ion bombardment is performed. That is, if necessary, an inert gas such as Ar or a gas such as H 2 or O 2 is supplied into the vacuum chamber 2 using the gas supply unit 9, and electric power is supplied from the plasma generation power source 10 between the substrates W. To generate glow discharge for surface cleansing.

Moreover, you may pre-heat with respect to the rotating base material W using the heater mentioned above. In addition, when another film supply source (sputter source, AIP (Arc Ion Placing) evaporation source, etc.) is provided in the vacuum chamber 2, using these film supply sources, a film and a substrate by plasma CVD are used. An intermediate layer inserted between W may be formed. The details of the formation of the intermediate layer will be described in detail in the fifth and sixth embodiments.

(Film formation)
Thereafter, the process gas is supplied into the vacuum chamber 2 using the gas supply unit 9.

The pressure at the time of film formation (that is, the pressure of the process gas) varies depending on the type of CVD film (process gas or reactive gas) to be formed, but a pressure of about 0.1 Pa to 1000 Pa is preferable. As described above, when the pressure during film formation is about 0.1 Pa to 1000 Pa, stable glow discharge can be generated, and film formation can be performed at a good film formation rate. . In addition, from the viewpoint of suppressing the generation of powder accompanying the reaction in the gas, the pressure during film formation is further preferably 100 Pa or less.

In forming the protective film by the plasma CVD method, the table is rotated and AC power is supplied from the plasma generation power source 10, so that the substrate W and the second group of the rotation table 4 belonging to the first group 18 are supplied. Glow discharge is generated between the rotating table 4 and the base material W belonging to 19, and plasma necessary for film formation is generated between the base materials W. The AC voltage supplied from the plasma generating power supply 10 is between 300 V and 3000 V (the peak value of the voltage between both electrodes) necessary for maintaining glow discharge. Further, the AC output power supplied from the plasma generation power source 10 is preferably about 0.05 to 5 W / cm ² in terms of power per unit area.

As described above, if the rotation tables 4 of the first group 18 and the rotation tables 4 of the second group 19 having opposite polarities are arranged alternately (alternately) in the circumferential direction, rotations adjacent to each other in the circumferential direction are performed. A potential difference always occurs between the substrates W held on the table 4, and glow discharge occurs between the substrates W. When the positive electrode and the negative electrode of the plasma generating power supply 10 are switched, the polarities of the rotating tables 4 adjacent in the circumferential direction are also switched, and glow discharge is continuously generated between the base materials W. Therefore, it is possible to perform film formation on a large number of substrates W at once and uniformly.

That is, when the base material W of the rotation table 4 belonging to the first group 18 acts as a working electrode and a CVD film is formed on the base W side, the base of the rotation table 4 belonging to the second group 19 is formed. The material W becomes a counter electrode (opposite electrode). When the positive electrode and the negative electrode of the plasma generating power source 10 are switched, the base material W of the rotation table 4 belonging to the second group 19 becomes the working electrode, and the base material W of the rotation table 4 belonging to the first group 18 is the counter electrode. It becomes.

That is, with the above-described configuration, even if the base material W is a counter electrode, the casing of the rotary table 5 or the vacuum chamber 2 does not become a counter electrode. Therefore, these members (that is, the casing of the turntable 5 and the vacuum chamber 2) do not act as glow discharge generating electrodes for generating plasma. For this reason, even if the insulating film is deposited thickly for a long time, plasma instability does not occur, and a CVD film without variations in film quality and thickness can be stably produced. Moreover, since these members do not act as discharge generating electrodes, they are not directly exposed to plasma that decomposes the source gas. For this reason, it is hard to deposit a film | membrane on these members compared with a prior art. For this reason, scattering of flakes caused by thick deposition of the film hardly occurs, and film defects are hardly generated.

(From open air to removal)
When the film formation process is completed, the output of the plasma generation power source 10 and the introduction of the process gas are stopped, and the film formation is completed. When the temperature of the base material W is high, the temperature is lowered if necessary, the inside of the vacuum chamber 2 is opened to the atmosphere, and the base material W is removed. If it does in this way, it will become possible to obtain the base material W in which the CVD film was formed in the surface.

(Example)
Next, an example of forming a protective film by the plasma CVD method using the plasma CVD apparatus 1 having the above-described configuration will be described.

The plasma CVD apparatus 1 is also equipped with a pulsed DC power source. By switching the electrical connection, a negative intermittent DC voltage can be simultaneously applied to the rotating shafts belonging to the two groups instead of the plasma generating power source 10. By such a method, it is possible to perform film formation equivalent to the prior art as a comparative example.

In the following, a tree-like work set as shown in FIG. 4B was mounted on all the rotation axes. And this work set itself is handled as a simulated base material, and the actual base material W is handled as a holder WH on a tree-like work set on one of six axes work set (simulated base material). A base material (test piece) W for evaluation was mounted on the top. In addition, as a kind of base material (test piece) W, (1) Test piece of silicon (Si) wafer (hereinafter referred to as test piece (1)), (2) Carbide test piece (hereinafter referred to as test piece (2) )), (3) A cemented carbide test piece (hereinafter referred to as test piece (3)) coated with an intermediate layer (Cr layer + WC layer, total film thickness 1 μm) in advance was used.

(From substrate set to vacuum exhaust)
First, a tree-like work set is mounted as a simulated base material on all the rotation axes. One of the simulated substrates is handled as the substrate holder WH, the substrate W is fixed, and the substrate W is set. When the base material W and the simulated base material are thus set, the inside of the vacuum chamber 2 is exhausted to a high vacuum state using the vacuum pump 3 (evacuation means 3).

(Ion bombard treatment)
Next, an inert gas such as Ar is introduced from the

gas supply unit

9 and 2 kW of electric power is applied at a pressure of 3 Pa while rotating the revolution table to generate a glow discharge for 30 seconds. Etching was performed for cleaning.

(Film formation)
Thereafter, acetylene is introduced as a process gas from the gas supply unit 9 at a flow rate of 700 sccm, and while maintaining a pressure of 2.5 Pa, the plasma generation power supply 10 is applied with 4 kW of power at a frequency of 70 to 80 kHz to grow it. Electric discharge was generated, and a film was formed on the surface of the simulated base material including the base material W. During the film forming process, arc discharge was sometimes observed, but the frequency was less than 5 times per minute, and the arc discharge was interrupted by the discharge interrupting mechanism of the plasma generation power source, and the time was about 100 msec. To return to normal discharge. Therefore, there was no abnormality in the film formation. The film formation rate was about 5 μm / Hr, and the film thickness was about 3 μm by adjusting the film formation time.

(From open air to removal)
When the film formation process is completed, the output of the plasma generation power source 10 and the introduction of the process gas are stopped, and the film formation is completed. The inside of the vacuum chamber 2 was opened to the atmosphere, and the formed substrate W was taken out.

A hard carbon film containing about 3 μm of hydrogen was formed on the surface of the treated substrate W. The formed film is a healthy and glossy film regardless of any test piece (1), test piece (2), or test piece (3). No peeling of the film was observed.

When the film hardness of the formed film was measured with a nanoindenter, it was found that the film hardness was 21 GPa. Moreover, when the adhesiveness of the film | membrane on a test piece (3) was evaluated using the scratch testing machine, the adhesiveness of the film | membrane was evaluated as 100 N or more. The result of the above film formation test is referred to as Example 1.

As a comparative example, the process up to the ion bombardment process was exactly the same as in Example 1, and in the film formation process, acetylene was introduced as a process gas at a flow rate of 700 sccm and maintained at a pressure of 2.5 Pa. An intermittent DC power of 4 kW at a frequency of 30 kHz, which is the maximum frequency of the power source, is simultaneously applied to the base material W of group A and the base material W of group B to generate glow discharge between the vacuum chamber 2 and the embodiment. A similar film formation was attempted. However, arc discharge occurs continuously, and it is difficult to apply predetermined power. When the inside of the vacuum chamber was observed, glow discharge was intermittently generated while arc discharge was generated at various locations on the base material holder. The test was terminated because scheduled power application was not possible. The above film formation test is referred to as Comparative Example 1. In order to solve the above-mentioned problems of frequent arc discharge, the intermittent voltage operation was stopped, and a method using a DC voltage application or another power source with a maximum frequency of 250 kHz was used to increase the frequency to 80 kHz. However, there was no significant change in the situation.

Based on the above problems, the level at which arc discharge does not occur frequently in the power from the pulse DC power source was investigated in the same manner as in Comparative Example 1. As a result, it was found that when the set power is 1.2 kW or less, the occurrence frequency of arc discharge is several times per minute.

For this reason, as another comparative example, the other steps are completely the same as in Example 1, and in the film forming step, acetylene is introduced as a process gas at a flow rate of 700 sccm and maintained at a pressure of 2.5 Pa. An intermittent direct current power of 1.2 kW at a frequency of 30 kHz, which is the maximum frequency of the power supply, is simultaneously applied to the base materials of the group A and the group B from the pulse DC power source to generate a glow discharge between the vacuum chamber and the embodiment. A similar film was formed. The film formation rate was 2.2 μm / Hr, and a film of about 3 μm was formed by adjusting the film formation time.

A hard carbon film containing about 3 μm of hydrogen was formed on the surface of the base material thus formed. The formed film was able to form a sound film regardless of the test piece (1), test piece (2), or test piece (3), and no peeling of the film was observed. However, the appearance of the film is slightly less glossy than Example 1. The film hardness of the formed film was measured using a nanoindenter. As a result, the film hardness was found to be 14 GPa. Moreover, the adhesiveness of the film | membrane on a test piece (3) was evaluated using the scratch testing machine. As a result, the adhesion of the film was evaluated as 80N. The result of the above film formation test is referred to as Comparative Example 2.

In Comparative Example 2, the film hardness decreased as a result of lowering the power. Therefore, a condition search was further performed to search for a condition that allows the application of as high a power as possible.

Based on the result, the other steps are the same as in Example 1, and in the film forming step, acetylene is introduced as a process gas at a flow rate of 100 sccm, and the pressure is supplied from the pulse DC power source while maintaining the pressure of 1 Pa. A 3.5 kW intermittent DC power at a maximum frequency of 30 kHz is simultaneously applied to the base materials of the A group and the B group to generate a glow discharge between the vacuum chamber and the same film formation as in the example. went. The film formation rate was 0.9 μm / Hr, and a film of about 2 μm was formed by adjusting the film formation time. The reason why the film thickness was 2 μm was that although a film formation of 3 μm was attempted, a sound film could not be formed with all the substrates, and the film thickness decreased.

A hard carbon film containing about 2 μm of hydrogen was formed on the surface of the substrate W thus formed. As for the formed film, a healthy glossy film was formed on the test piece (3), but partial peeling was observed on the test piece (1) and the test piece (2). The film hardness of the formed film was measured using a nanoindenter. As a result, the film hardness was found to be 24 GPa. Moreover, the adhesiveness of the film | membrane on a test piece (3) was evaluated using the scratch testing machine. As a result, the adhesion of the film was evaluated as 50N. The result of the above film formation test is referred to as Comparative Example 3.

Comparing the film formation conditions of Example 1 and Comparative Example 1, it is found that when the same process conditions are set, the method of the present invention suppresses abnormal discharge and greatly improves the film formation stability. It was. This is because, in the method of the comparative example, since the glow discharge is excited by the intermittent DC voltage, the substrate is biased to a negative potential and is at a potential that attracts ions in the plasma. On the other hand, according to the film forming method of the present invention, the substrate has a negative potential with respect to the plasma and attracts ions in the plasma, and the substrate has a positive potential with respect to the plasma and the ions in the plasma repel and emit electrons. Experience the same period of attraction.

Although it is speculated from here, when an insulating film such as DLC or SiOx is formed on the surface of a conductive metal substrate, the substrate being formed is a composite of a conductive metal and an insulating film. Become a body. Therefore, as in the present invention, the period during which the substrate attracts ions during film formation and the period during which electrons are attracted are equivalent, so that charge-up is unlikely to occur, and arc discharge is relatively high power. It is thought that it does not occur to the level.

When the film formation state of Example 1 and the film formation state of Comparative Example 2 are compared, in the film formation method of the present invention, when the same gas condition is set, a larger electric power can be input. Can be formed at high speed.

For the purpose of investigating the cause of the large difference related to the adhesion of the film observed between Example 1 and Comparative Example 3, the internal stress of the film was measured by the warp of the base material using the test piece (1). As a result, the compressive stress of 0.6 GPa was observed in the test piece of Example 1, while the compressive stress of 2.8 GPa was observed in the test piece of Comparative Example 1. From these results, it is considered that the large difference in adhesion is due to the difference in the level of compressive stress of the formed film.

In the same manner, the film formation conditions were changed at the time of film formation, and the film formation process was performed, and Examples 2 to 3 were created as the evaluation results. These results are shown in the table below.

As can be seen from this table, in the method for forming a protective film according to the present invention, if other conditions are the same, high power can be applied, and as a result, a high-speed film can be formed. In addition, the film formed by the method for forming a protective film according to the present invention can form a film having low film stress and excellent adhesion as compared with the conventional forming method. This is thought to be due to the following mechanism.

5A and 5B show a change in potential during film formation in the method for forming a protective film according to the present invention in comparison with the prior art.

In the case of the conventional method for forming a protective film, a negative DC potential is intermittently applied to the substrate W when glow discharge is excited, as shown in FIG. 5B. For this reason, the film formed on the substrate W is formed while receiving a positive ion bombardment (bombardment) from plasma except for a short time when it is positively biased. For this reason, it is presumed that the film being formed is formed while continuously receiving ion implantation, and a large compressive stress is generated in the film. As a result, it is easy to obtain a high hardness in the film, but the adhesion of the film is relatively poor due to the influence of compressive stress.

On the other hand, in the case of the method for forming a protective film according to the present invention, as shown in FIG. 5A, the glow discharge is excited by an alternating voltage applied between the A group of base materials W and the B group of base materials W. It is done by. For this reason, a negative potential is applied to the half during film formation and bombarded by positive ions in the plasma, but a low positive potential is applied during the remaining half of the period, and only electrons in the plasma flow in, causing ion bombardment. There is no period. During the period when a negative potential is applied, ions are implanted in the same way as in the prior art, but in the remaining period, the impact of electrons becomes the central period and it is estimated that the effect of mitigating the impact of ions occurs. . As a result, it is considered that the compressive stress in the film is reduced and a film having relatively excellent adhesion can be formed.

In order to develop such a mechanism, it is important to set the frequency of the AC plasma generation power source 10 to an appropriate range. If the frequency of the plasma generating power supply 10 is too high, ions in the plasma cannot follow the change in potential, and the situation where the ion irradiation of the present invention occurs intermittently is not formed. For this purpose, it is necessary that the frequency of the plasma generation power source 10 be 1 MHz or less at which ions can follow. On the other hand, if the frequency of the plasma generating power supply 10 is too low, charge-up occurs between the switching of positive and negative voltages, and arc discharge is likely to occur. Therefore, the frequency of the plasma generating power source 10 is preferably 1 kHz or higher, and more preferably 10 kHz or higher.

As described above, according to the method for forming a protective film according to the first embodiment of the present invention using the plasma CVD apparatus 1, a CVD film is difficult to deposit on a portion other than the base material, and cleaning is not performed for a long time. Stable operation is possible. In addition, production efficiency is high while maintaining stable film formation conditions. Furthermore, it is possible to form a film having low film stress and excellent adhesion.

<Second Embodiment>
Hereinafter, the plasma CVD apparatus 21 according to the second embodiment of the present invention will be described with reference to FIG. The plasma CVD apparatus 21 according to the second embodiment does not rotate the substrate W, whereas the plasma CVD apparatus 1 according to the first embodiment described above is an apparatus that revolves the substrate. The difference is that it is stationary. That is, the base material W is stopped at a position where one group and the other group face each other, and a protective film is formed on the surface of the base material W. Other than that, the second embodiment is the same as the first embodiment, and therefore, the same parts as those described above are not repeated here.

As shown in FIG. 6, the plasma CVD apparatus 21 does not include the self-revolving table 5 (or includes the rotary table 5, but may not rotate the rotary table 5), and has a rectangular shape. A protective film is formed on the substrate by a plasma CVD method with the stainless steel plates facing each other. In this case, the stainless steel plate itself may be a base material holder WH provided with a large number of holes, and the base material W may be held in the holes. Further, the stainless steel plate itself may be the base material W. In the following description, it is assumed that the stainless steel plate itself is the base material W.

Note that the notations “A” and “B” in FIG. 6 are the same as “A” and “B” in the first embodiment, and are two groups into which the base material is divided, and one group Is electrically insulated from the chamber potential and the other group, and is connected to both electrodes of a plasma generation power source 10 for generating plasma. In the example shown in FIG. 6, the base material of one group A and the base material of the other group B are alternately arranged, so that these base materials are arranged to face different groups of base materials. is doing.
Similar to the first embodiment, the stainless steel plate (base material W) was placed in the vacuum chamber 22 and the process up to the etching process was completed.

As an example, in the film forming process, HMDSO is introduced as a process gas at a pressure of 2.5 Pa, and 2 kW of electric power is applied from the plasma generation power source 10 to generate glow discharge. ) And a group B base material W (stainless steel plate), a glow discharge was generated, a film was formed on the surface of the base material W, and taken out to the atmosphere.

A film containing about 2 μm of Si, C, O, and H as a component was formed on the surface of the base material W thus formed. This film has water repellency and, for example, has a characteristic that it can be easily removed even if an adhesive resin adheres. The adhesive tape adhered to the film in this way can be easily peeled off by spraying water at a high pressure.

On the other hand, as a comparative example, a glow discharge was generated between the vacuum chamber 22 by simultaneously applying 2 kW of power from the pulse DC power source to the group A base material W and the group B base material W in the film forming process. Except for the above, the same treatment was performed to form a film on the surface of the substrate W, and the substrate W was taken out to the atmosphere. A substantially similar film was formed on the surface of the base material W thus formed, but slight peeling was observed at the corners of the stainless steel plate. The characteristics of the film have water repellency as in the examples. Similarly, in the test in which the adhesive tape was removed by spraying water, the peeling of the film expanded from the above-mentioned peeling site.

For this reason, even if the coating film to be formed and the situation of the base material arrangement are different, according to the method for forming a protective film by the plasma CVD method according to the present invention, a film having relatively excellent adhesion is formed. can do.

<Preferred form relating to coating material applicable to the embodiment>
Below, the preferable form in connection with film | membrane material is demonstrated.

(1) The gas supplied into the vacuum chamber includes a hydrocarbon gas such as acetylene, methane, benzene, toluene, ethane, and ethylene. The formed film is a hydrogen-containing carbon film called DLC or the like.
(2) The gas supplied into the vacuum chamber includes a hydrocarbon gas such as acetylene, methane, benzene, toluene, ethane, and ethylene. The formed film is a carbon film having conductivity.
(3) Gas supplied into the vacuum chamber contains hydrocarbon gas such as acetylene, methane, benzene, toluene, ethane, ethylene, and silane, TMS, HMDSO, HMDSN, etc., and the formed film contains silicon. It is a film containing C, Si, and H as essential elements called DLC.
(4) The gas supplied into the vacuum chamber contains a hydrocarbon gas such as acetylene, methane, benzene, toluene, ethane, and ethylene as a main component, and a gas containing a metal (TMS, TTIP, etc.) as an additional component. Include as. The formed film is a carbon film containing a metal element called Me: DLC.
(5) The gas supplied into the vacuum chamber includes an organosilane-based gas containing Si as an essential element, such as TMS, HMDSO, and HMDSN. The formed film is a protective film containing Si, C, and H as essential elements.
(6) The gas supplied into the vacuum chamber includes an organosilane-based gas containing Si as an essential element, such as silane, TMS, HMDSO, and HMDSN. A film formed by mixing an oxidizing gas (such as oxygen) with this is a protective film containing Si, O, C, and H as essential elements.
(7) The gas supplied into the vacuum chamber includes an organosilane-based gas containing Si of silane, TMS, HMDSO, and HMDSN as an essential element. A film formed by mixing a gas containing nitrogen (nitrogen gas, ammonia, etc.) with this is a protective film containing Si, N, C, and H as essential elements.

<Preferred embodiment relating to a substrate applicable to the embodiment>
Below, the preferable form in connection with a base material is demonstrated.

Regarding the film formation method, the base material must have a certain degree of conductivity. This is because the AC voltage applied to the base material is lower than a so-called RF (Radio Frequency) high frequency, and for example, insulating glass is not an object of this film forming method.

(1) Preferred substrates include metals, conductive ceramics, plastics / glasses having a conductive film formed on the surface, and the like. In addition, a silicon base material doped with an impurity element to provide conductivity is also a target. This is necessary to effectively transmit the voltage for creating the plasma across the substrate.
(2) In the conventional film formation method, such a protective film can be coated on, for example, cemented carbide, ceramics, tool steel, mold steel used for tools and molds, or automotive parts. In many cases, a carburized material, a nitrided material, a heat-treated material and the like whose hardness generally exceeds 10 GPa are used. This is based on the idea that a coating with higher hardness is applied to the surface of such a high hardness material. This is because they often peel off without being able to follow the deformation.
(3) Needless to say, it is also preferable to use such a hard substrate in the method for forming a protective film by the plasma CVD method according to the present invention. Rather, when a film is formed on a substrate having a relatively low hardness, the difference from the prior art becomes noticeable. This is because the method for forming a protective film by the plasma CVD method according to the present invention has a characteristic that the film stress is relatively low and can easily follow the deformation of the substrate. In addition, in the method for forming a protective film by the plasma CVD method according to the present invention, it is advantageous that a thick coating is possible when applied to an object having a relatively low hardness.
(4) From such a viewpoint, as a suitable base material for the method for forming a protective film by the plasma CVD method according to the present invention, a steel material and stainless steel that are not surface-hardened, a non-ferrous metal that does not have a very high hardness ( Titanium, aluminum, aluminum alloy, magnesium alloy), plastics with conductive surface treatment (for example, plating), and the like are more advantageous than the conventional method.
(5) The above description is based on the premise that the method for forming a protective film by the plasma CVD method according to the present invention applies that the surface has conductivity. However, as an exception, an insulating member that is thinly coated on the surface of a conductive material can be an object of the method for forming a protective film by the plasma CVD method according to the present invention. This is because when the insulating layer is thin, an alternating voltage can be transmitted through the capacitance of the insulating layer. The applicable insulating layer thickness varies depending on the frequency of the power source. For example, when a frequency range of several tens of kHz is used, the thickness of the insulating layer cannot exceed 1 mm and is preferably up to about 200 μm.

<Preferable form relating to mounting form of base material applicable to the embodiment>
In the following, preferred forms relating to the mounting form of the base material, and particularly preferred forms will be listed, focusing on the mounting form of the base material divided into two groups.

(1) The embodiment disclosed as the first embodiment, which has a self-revolving table and whose rotation axis is divided into a group A and a group B (FIG. 1). Furthermore, the form which has two or more pairs of this self-revolving table.
(2) A form disclosed as the second embodiment, in which a plurality of flat base materials or base material holders belong alternately to the A group and the B group (FIG. 2).
(3) A mode having at least one pair of rotary tables, which will be described later as a third embodiment, and each rotary table and a substrate mounted thereon are divided into a group A and a group B. A plasma CVD apparatus 31 according to the third embodiment shown in FIGS. 7 and 8 has two pairs of rotary tables in a vacuum chamber 32.
(4) A mode in which one or more pairs of self-revolving tables, which will be described later as a fourth embodiment, are provided, and each self-revolving table and the substrate mounted thereon are divided into a group A and a group B. A plasma CVD apparatus 41 according to the fourth embodiment shown in FIG. 9 has two pairs of rotary tables in a vacuum chamber 42.
(5) A form in which two flat substrate holders are arranged to face each other, and a plurality of substrates are fixed to the facing surfaces of the substrate holders.
(6) A mode in which a rotary table (including a self-revolving table) is arranged in two upper and lower layers, and a base material arranged on the upper and lower two-layer table is divided into a group A and a group B.

<Third Embodiment>
Hereinafter, a plasma CVD apparatus 31 that realizes the protective film forming method according to the third embodiment of the present invention will be described.

FIG. 7 shows a perspective view of the entire configuration of the plasma CVD apparatus 31, and FIG. 8 shows a top view thereof.

In this plasma CVD apparatus 31, a base material is installed on two rotary tables 5 (5A, 5B) arranged in a vacuum chamber 32. The base material shown in FIG. 7 is schematically represented by a cylinder. The actual items are piston rings, rocker arms, cutting tools, piston pins, etc. These relatively small parts are mounted on a jig so that the jig and parts can be integrated into a cylindrical space. is there. And the some base material mounted on the same turntable 5 comprises the group. Since there are two turntables 5, the plurality of base materials are divided into two groups (Group A and Group B). Each turntable 5 is electrically insulated between the chamber potential and the mutual group, and is connected to both electrodes of the plasma generating power source 10 for generating plasma.

Since parts other than these configurations are the same as those in the first embodiment, the same parts as those described above will not be repeated here.

When the method for forming a protective film according to the first embodiment described above is performed using this plasma CVD apparatus 31, a CVD film is unlikely to deposit on portions other than the substrate W, and stable operation can be performed without cleaning over a long period of time. Is possible. In addition, production efficiency is high while maintaining stable film formation conditions. Furthermore, it is possible to form a film having low film stress and excellent adhesion.

<Fourth Embodiment>
Hereinafter, a plasma CVD apparatus 41 that realizes the protective film forming method according to the fourth embodiment of the present invention will be described.

A perspective view of the overall configuration of the plasma CVD apparatus 41 is shown in FIG.

In this plasma CVD apparatus 41, a plurality (four in this case) of rotation tables 4 that hold the substrate W, which is a film formation target, in a state of rotation are provided on the rotation table 5. That is, the plurality of rotation tables 4 are arranged on the rotation table 5, and the rotation table 5 provided with the plurality of rotation tables 4 in the plasma CVD apparatus 21 is used as the rotation axis of the rotation table 4 (rotation axis P). A rotation mechanism 8 that revolves around a revolution axis Q that is parallel to the axis is provided. In the plasma CVD apparatus 21, a plurality of (here, two) turntables 5 are arranged symmetrically with respect to the center line of the plasma CVD apparatus 1 in the vacuum chamber 22. Further, the vacuum exhaust means 3 is provided on this center line. Here, the number of turntables 5 is not particularly limited as long as it is arranged so as to be symmetric with respect to the center line of plasma CVD apparatus 1. The number of the rotation tables 4 provided per one rotation table 5 is not particularly limited, but it is desirable that the rotation tables 5 are arranged so as to have the same number even if they are different. Further, each of the plurality of rotation tables 4 is arranged to have an equal radius from the revolution axis of the rotary table 5 and at equal intervals around the revolution axis Q.

When the method for forming a protective film according to the first embodiment described above is performed using the plasma CVD apparatus 41, more base materials W can be formed at a time than in the first embodiment. In addition, production efficiency is high while maintaining stable film formation conditions. Furthermore, it is possible to form a film having low film stress and excellent adhesion.

<Fifth Embodiment>
Hereinafter, a plasma CVD apparatus 51 according to a fifth embodiment of the present invention will be described. The plasma CVD apparatus 51 according to the fifth embodiment includes the plasma CVD apparatus 1 according to the first embodiment described above and a film supply source (sputter evaporation source, arc evaporation source) that forms an intermediate layer on the substrate. Is different. Other than that, the second embodiment is the same as the first embodiment, and therefore, the same parts as those described above are not repeated here.

As shown in FIG. 10, the plasma CVD apparatus 51 includes a film supply source 6 (sputter evaporation source, arc evaporation source, etc.) for forming a film different from the protective film by the plasma CVD method in the vacuum chamber 52. In the following description, an arc evaporation source 6 or a sputter evaporation source 6 will be described). In the film forming process, an intermediate layer to be inserted between the film formed by plasma CVD and the substrate W is formed using the arc evaporation source 6.

When the protective film is formed by the plasma CVD method, alternating current power is supplied from the plasma generation power source 10 and the substrate W and the second group of the rotation table 4 belonging to the first group 18 (see FIGS. 1 and 2). Glow discharge is generated between the rotating table 4 and the base material W belonging to 19 (see FIGS. 1 and 2), and plasma necessary for film formation is generated between the base materials W.

As described above, if the rotation tables 4 of the first group 18 and the rotation tables 4 of the second group 19 having opposite polarities are arranged alternately (alternately) in the circumferential direction, rotations adjacent to each other in the circumferential direction are performed. A potential difference always occurs between the base materials W held on the table 4, and a glow discharge is surely generated between them. When the positive electrode and the negative electrode of the plasma generating power source 10 are switched, the polarities of the rotating tables 4 adjacent in the circumferential direction are also switched, and glow discharge is continuously generated between the two. Therefore, it is possible to perform film formation on a large number of substrates W at once and uniformly.

That is, if it is the above-mentioned structure, even if the base material W becomes a counter electrode, the housing | casing of the turntable 5 and the vacuum chamber 2 will not become a counter electrode. Therefore, these members do not act as glow discharge generating electrodes for generating plasma. Even if the insulating film is deposited thick for a long time, plasma instability does not occur, and it is possible to stably produce a CVD film having no variation in film quality and thickness. Moreover, since these members do not act as discharge generating electrodes, they are not directly exposed to plasma that decomposes the source gas. For this reason, it is hard to deposit a film | membrane on these members compared with a prior art. For this reason, scattering of flakes caused by thick deposition of the film hardly occurs, and film defects are hardly generated. In addition, the coating itself represented by metal-containing DLC is somewhat conductive. However, in this case as well, there remains an effect that the film is difficult to be deposited on the housing of the vacuum chamber 52, flakes are hardly scattered, and film defects are hardly generated. In addition, even when a certain conductive film such as metal-containing DLC is formed on the base material, a film with poor insulating properties may be formed in the chamber portion where plasma is weak. . In such a case, the effect of preventing plasma destabilization also appears.

Thus, in this plasma CVD apparatus 51, the arc evaporation source 6 is installed in the vacuum chamber 52. A CVD film containing an additive element can be formed by operating the arc evaporation source 6 while forming a film by plasma CVD. More preferably, as shown in FIG. 10, there is a region partitioned by a partition member in the vacuum chamber 52. An arc evaporation source 6 is installed in this region. As shown in FIG. 10, the arc evaporation source 6 has a rectangular flat plate shape.

The partition member that partitions the partition is electrically connected to the vacuum chamber 52 and also functions as an anode of the arc evaporation source 6. The evaporation material (target) mounted on the arc evaporation source 6 acts as a cathode. From the arc spot generated on the surface of the evaporation material, the electrons carrying the discharge current and the vapor of the evaporation material are ejected in an ionized state, and plasma is formed in front of the arc evaporation source 6. Electrons in the plasma flow into the partition member, and the partition member acts as an anode.

* The partition member that divides the partition has an opening. Through this opening, the substrate can be irradiated with metal vapor evaporated by arc discharge. It is possible to form a film in which a metal is mixed in a CVD film formed by glow discharge plasma.

On the other hand, plasma generated in the arc evaporation source with the supply of metal vapor affects the state of glow discharge. However, the operating state of the glow discharge can be controlled by adjusting the power for exciting the glow discharge. The deposition rate of plasma CVD is not limited by the operation of the arc evaporation source 6.

The inside of the partition region communicates with the film forming region around the base material W of the vacuum chamber 52 through the opening, but the atmosphere is blocked except for that, and can be controlled to different gas atmospheres. In particular, when a gas other than the CVD film forming gas (non-film forming gas) is supplied to the partition region, the partition region has a higher pressure than the film forming region, and the non-film forming gas is supplied to the partition region of the film forming gas. Prevent inflow. The supply gas is preferably an inert gas (Ar, Ne, He, Kr, Xe, etc.). Further, even a reactive gas may be a gas that does not form an insulating compound when combined with the evaporation material of the arc evaporation source 6, such as nitrogen gas.

When the arc evaporation source 6 is operated in such a state, even if the film forming gas flows into the partition region, a film that maintains conductivity can be formed on the inner surface of the partition region that is operating as the anode. . Therefore, an insulating film that impairs the stability of discharge, which has been a problem in the past, is not deposited, and stable operation is possible.

In addition, the pressure at the time of film formation differs depending on the film type and the mounted evaporation source.

When the arc evaporation source 6 is mounted, a pressure of about 0.1 Pa to 10 Pa is preferable. Although depending on the gas component, if it is less than 0.1 Pa, it is difficult to generate a stable glow discharge, and the deposition rate depends on the gas pressure, so a pressure of 1 Pa or more is more preferable. This is because at a pressure exceeding 10 Pa, the pressure is too high and the metal element supplied from the arc evaporation source 6 does not easily reach the substrate.

In addition, when a sputter evaporation source is installed, it is desirable to keep the partial pressure of the film forming gas in the atmosphere within a range where no CVD film is deposited on the sputter evaporation source. The pressure of the film forming gas needs to be less than 0.5 Pa.

In the plasma CVD apparatus 51 equipped with the arc evaporation source 6, ion bombarding is performed by applying a negative voltage of 500 to 1000 V to the substrate while irradiating metal ions supplied from the arc evaporation source 6. It is also possible. This process is sometimes called metal ion bombardment.

By the way, the plasma CVD apparatus 51 described above has six rotation tables 4 arranged on the rotation table 5. However, various patterns are conceivable for the number and arrangement of the rotating tables 4 on the rotating table 5.

<Sixth Embodiment>
Hereinafter, a plasma CVD apparatus 61 according to a sixth embodiment of the present invention will be described. Note that the plasma CVD apparatus 61 according to the sixth embodiment differs from the plasma CVD apparatus 51 according to the fifth embodiment described above in the holding state of the substrate W on the turntable 5. Other than that, it is the same as the fifth embodiment, and therefore, the same parts as those described above are not repeated here.

The plasma CVD apparatus 61 according to the sixth embodiment of the present invention is a film supply source in addition to the configuration of the plasma CVD apparatus 31 according to the third embodiment or the plasma CVD apparatus 41 according to the fourth embodiment. A sputter evaporation source 6 is provided. That is, in this plasma CVD apparatus 61, the sputter evaporation source 6 is installed so that vapor can be supplied to both of the two rotary tables 5. With this configuration, the plasma CVD coating is formed by glow discharge generated between the two groups of substrates mounted on the two turntables 5. Decomposition of the film forming gas occurs exclusively around the base material and hardly adheres to the vacuum chamber 62. As a result, the sputter evaporation source 6 installed for supplying the additive element can be stably operated for a long time.

The specific embodiments described above mainly include inventions having the following configurations.

That is, the method for forming a protective film of the present invention is a method of forming a protective film on the surface of a plurality of conductive substrates by plasma CVD, and the plurality of substrates are divided into two groups, Mounting a substrate in the chamber in a state in which the group and the other group and the chamber are electrically insulated; setting a vacuum state in the chamber; and supplying a process gas including a deposition gas in the chamber And forming a protective film on the surface of the substrate by generating discharge plasma between the substrates by supplying AC power between the two groups of substrates. Features.

Preferably, in the step of forming the protective film, the one group becomes a negative potential and operates as a working electrode which plays a main role in generating discharge plasma, and the other group becomes a positive potential and operates as a counter electrode. The first state to be performed and the second state in which the first state and the positive / negative of the potential are switched are alternately and temporally repeated to generate discharge plasma between the two groups of base materials. can do.

More preferably, the AC power is at least one of a sine waveform, a positive and negative alternating rectangular waveform, a waveform in which successive pulses of the same polarity appear alternately, and a waveform in which a rectangular wave pulse is superimposed on a sine waveform. It can be configured to be represented by two waveforms.

More preferably, the frequency of the AC power can be configured to be within a range of 1 kHz to 1 MHz.

More preferably, the frequency of the AC power can be configured to be within a range of 10 kHz to 400 kHz.

More preferably, it may be configured to further include a step of irradiating the base material with vapor of evaporating material.

More preferably, a protective film can be formed on the surface of the base material while irradiating the base material with vapor of an evaporation material.

More preferably, a protective film can be formed on the surface of the base material while rotating the base material.

More preferably, a protective film can be formed on the surface of the base material by stopping the base material at a position where the one group and the other group face each other.

By using the method for forming a protective film of the present invention, it is difficult for a CVD film to be deposited on portions other than the base material. Stable operation is possible without cleaning for a long time. In addition, production efficiency is high while maintaining stable film formation conditions. And a protective film with high adhesiveness to a base material can be formed.

By the way, the present invention is not limited to the above-described embodiments, and the shape, structure, material, combination, and the like of each member can be appropriately changed without changing the essence of the invention. Further, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. However, matters that can be easily assumed by those skilled in the art are employed.

Claims

A method of forming a protective film on the surface of a plurality of conductive substrates by plasma CVD,
Dividing the plurality of substrates into two groups, mounting the substrate in the chamber in a state where one group and the other group and the chamber are electrically insulated; and
Creating a vacuum in the chamber;
A process gas including a film forming gas is supplied into the chamber, and an alternating current power is supplied between the two groups of substrates to generate discharge plasma between the substrates to protect the surface of the substrate. Forming a film;
A method for forming a protective film comprising:
In the step of forming the protective film, the one group becomes a negative potential and operates as a working electrode that plays a main role in generating the discharge plasma, and the other group becomes a positive potential and operates as a counter electrode. The first state and the second state in which the first state and the positive / negative of the potential are interchanged are alternately repeated in time to generate the discharge plasma between the two groups of substrates.
The method for forming a protective film according to claim 1.
The AC power is expressed by at least one of a sine waveform, a positive and negative alternating rectangular waveform, a waveform in which consecutive pulses of the same polarity appear alternately, and a waveform in which a rectangular wave pulse is superimposed on a sine waveform. To be
The method for forming a protective film according to claim 1.
The frequency of the AC power is in the range of 1 kHz to 1 MHz.
The method for forming a protective film according to claim 1.
The frequency of the AC power is in the range of 10 kHz to 400 kHz.
The method for forming a protective film according to claim 4.
Further comprising irradiating the substrate with vapor of evaporating material;
The method for forming a protective film according to claim 1.
Forming a protective film on the surface of the base material while irradiating the base material with vapor of evaporating material;
The method for forming a protective film according to claim 6.
The method for forming a protective film according to claim 1, wherein the protective film is formed on the surface of the base material while rotating the base material.
The method for forming a protective film according to claim 1, wherein the base material is stopped at a position where the one group and the other group face each other to form a protective film on the surface of the base material.