JP2001234340A - Amorphous hard carbon film and its deposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film deposition method for obtaining an amorphous hard carbon film good in wear resistance, sliding characteristics and adhesion by a relatively simple procedure. SOLUTION: A high-frequency signal is applied to the space between two electrodes 2 and 3 arranged in a confronted state in an evaporation chamber 1 held to a vacuum with a high-frequency generator 5, a pulse modulator 6 and a matching circuit 7 in a pulse way with a prescribed repeated cycle, a prescribed pulse width and a prescribed high-frequency power, and moreover, reaction gas is introduced therein to cause plasma reaction, so that an amorphous hard carbon film is deposited on a substrate 4 placed on the second electrode 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, an amorphous hard carbon film and a method for forming the same, and more particularly, to a film having improved wear resistance, sliding characteristics, and adhesion.

[0002]

2. Description of the Related Art Amorphous hard carbon films have attracted attention as hard coating materials for mechanical parts and the like because of their relatively high hardness. As a method of forming the amorphous hard carbon film, for example, there is a method of forming a film having a thickness of several μm on a substrate made of an iron alloy or an aluminum alloy by a continuous discharge RF plasma CVD method or the like. The amorphous hard carbon film formed by the method described above has a drawback that the amorphous hard carbon film is easily peeled off due to residual stress caused by thermal stress, pressure stress, and the like generated during the formation. In order to solve such a disadvantage, for example, Japanese Patent Application Laid-Open No. Sho 58-126972 discloses that an intermediate layer is formed between a substrate on which an amorphous hard carbon film is formed and an amorphous hard carbon film. Has been proposed, and in Japanese Patent Application Laid-Open No. 4-300287,
It has been proposed to improve the adhesion by controlling the hydrogen concentration in the film.

[0003]

However, in the former method, the procedure of film formation is complicated, and as a result, the cost of machine parts and the like using an amorphous hard carbon film as a coating material is increased. There were problems such as invitation. In addition, the latter method has a problem that it cannot be said that it is at a level that can sufficiently withstand the use of actual mechanical parts. The present invention has been made in view of the above-described circumstances, and has a relatively simple film-forming procedure, compared with the prior art, abrasion resistance, sliding characteristics and good adhesion of an amorphous hard carbon film and the same. It is intended to provide a film forming method. Another object of the present invention is to provide a method of forming an amorphous hard carbon film which can be realized by adding a simple modification to a conventional manufacturing apparatus. Another object of the present invention is to provide a film forming method that requires a small increase in the temperature of the substrate.

[0004]

In order to achieve the above object, a method for forming an amorphous hard carbon film according to the present invention comprises:
A first and a second electrode are disposed in a vapor deposition chamber held in a vacuum, facing each other, a signal source for generating a high-frequency signal is connected to the second electrode, and a high-frequency high-frequency signal is applied between the two electrodes. And applying a reaction gas to cause a plasma reaction to occur, and forming an amorphous hard carbon film by vapor deposition on a substrate mounted on the second electrode surface, wherein the high-frequency signal is Is applied in a pulsed manner with a predetermined repetition period, a predetermined pulse width, and a predetermined high-frequency power to obtain an amorphous hard carbon film.

[0005] The amorphous hard carbon film obtained by such a film forming method has a conventional amount of wear of the film in a non-lubricated atmosphere, a coefficient of friction and a wear amount of a partner material, and a wear amount of a partner material in light oil. It is reduced as compared with that by the membrane method,
It exhibits high adhesion without providing a so-called intermediate layer as in the related art. In particular, the predetermined repetition cycle is:
40 Hz or more, the predetermined time is 150 μsec or more, and the predetermined high-frequency power is 1 per unit area of the electrode.
It is preferable that it is 8 W / cm ² or more. Further, it is preferable to use C ₆ H ₆ as a reaction gas.

Further, it is preferable that the reaction gas is supplied into the deposition chamber in synchronization with the application timing of the pulsed high-frequency signal.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. The members, arrangements, and the like described below do not limit the present invention, and can be variously modified within the scope of the present invention. First, a configuration of a pulse RF plasma CVD apparatus used for forming an amorphous hard carbon film according to an embodiment of the present invention will be described with reference to FIG. First, this pulse RF plasma CVD apparatus is based on a conventionally known and well-known RF plasma CVD apparatus, and is configured to perform an intermittent discharge as described later in place of the conventional continuous discharge. It is. In the vapor deposition chamber 1 held in a vacuum state, a first electrode 2 that is grounded externally and a second electrode 3 to which a high-voltage high-frequency signal described later is applied appropriately face each other. It is provided at a great distance. And the second electrode 3
A substrate 4 on which an amorphous hard carbon film is formed is mounted thereon. The size of the first and second electrodes 2 and 3 in the embodiment of the present invention is 1600 c
It was used in m ^2.

A high-frequency generator 5 as a signal source, a pulse modulator 6, and a matching circuit 7 are provided outside the vapor deposition chamber 1, and a continuous high-frequency wave generated by the high-frequency generator 5 is provided. , Pulse modulated by the pulse modulator 6,
A pulse-modulated high-frequency signal is applied to the second electrode 3 via a matching circuit 7 provided for achieving electrical matching between the pulse modulator 6 and the second electrode 3. I have.

Here, the high-frequency generator 5 and the matching circuit 7
Has basically the same configuration as that of the conventional device except for its electrical capacity. On the other hand, the pulse modulator 6 performs pulse modulation on a continuous wave signal of a predetermined frequency output from the high frequency generator 5 so that the continuous signal is intermittent as shown in FIG. , In other words, a continuous wave signal is output in a pulsed manner. Such a signal is applied to the second electrode 3 via the matching circuit 7. FIG. 3A schematically illustrates the power of the above-described high-frequency signal applied to the second electrode 3. In addition, evaporation chamber 1
Since negative ions collect around the second electrode 3 due to the plasma reaction, the timing of the high-frequency signal applied to the second electrode 3 as shown in FIG. Self-bias to a negative potential state in synchronism with.

A source gas is introduced into the vapor deposition chamber 1. That is, in the first tank 9,
The raw material gas is sealed, and the raw material gas in the first tank 9 is supplied to the first flow controller 11 and the first control valve 1.
3 and is introduced into the vapor deposition chamber 1. Here, in the case where the first control valve 13 supplies a pulse of the reaction gas to be described later, for example, a piezo valve configured to be able to perform a pulse-like opening / closing operation control using a piezo element is used. Is preferred. Further, a route pump 15, an axial flow molecular pump 16, and a pressure control valve 17 are provided outside the deposition chamber 1.
An axial flow molecular pump 16 is connected to the vapor deposition chamber 1 via a pressure control valve 17 so that the inside of the vapor deposition chamber 1 can be evacuated.

Next, a pulse R having the above-described configuration is used.
The conditions for forming the amorphous hard carbon film by the F plasma CVD apparatus, the film formation results, and the like will be described. First, in the embodiment of the present invention, a film was formed under the following film forming conditions.

Pulse RF power: 40 kW Base frequency: 13.56 MHz Pulse frequency: 40 Hz (period = 25 msec) Pulse width: 150 μsec Duty ratio: 1/167 (0.6%) Reaction pressure: 5.8 Pa Source gas: C ₆ H ₆ (benzene) Source gas flow rate: 30 sccm Substrate: High-speed tool steel (SKH51) and bearing steel (SUJ)
2)

Here, the pulse RF power indicates the peak value of the input power of the high frequency generator 5. The base frequency is the frequency of a high-frequency signal generated by the high-frequency generator 5. The pulse frequency is such that a high-frequency signal is intermittently applied to the second electrode 3 as shown in FIG. 3C, and the application period is converted into a frequency, that is,
This is a value obtained as f (MHz) = 10 ⁻⁶ / (a + b). Here, as shown in FIG. 3C, a and b represent a pulse width, that is, an on period of a pulse, and b represents an off period of a pulse. It is assumed to be seconds (sec). The pulse width is shown in FIG.
As shown in (C), this represents a time interval a at which the high-frequency signal is output in a pulsed manner. The duty ratio is a ratio a / b (see FIG. 3C) between the above-described pulse width and the output stop time b of the high-frequency signal output in a pulsed manner.
The reaction pressure is a pressure in the vapor deposition chamber 1. The substrate is a member on which a film is formed, and for the two types as described above,
Film formation was performed under the above film formation conditions.

Under these conditions, the deposition rate is at most 2.
It was 5 μm / hr. The characteristics of the amorphous hard carbon film thus obtained are as follows. First, the fine hardness of the obtained amorphous hard carbon film is 18000MP at maximum.
a. The coefficient of friction is 0.0
45, 0.1 was obtained in lubricating oil. The friction depth of the film was 0.15 μm in a non-lubricated atmosphere and 0.04 μm in a lubricating oil. Further, the wear diameter of the mating material was 0.16 mm in both the unlubricated atmosphere and the lubricating oil. Further, in a so-called scratch test, a scratch load of 50 N or more could be obtained without providing a conventional intermediate layer. The wear test performed to obtain friction and wear characteristic data such as a coefficient of friction was performed using a so-called ball-on-disc wear tester which is conventionally known and well-known. This will be described in detail in the description of FIG. 4 relating to comparison of the characteristics with the conventional film. Further, in the film forming method according to the embodiment of the present invention, since the high-frequency signal applied to the second electrode 3 is intermittent (pulsed), the temperature rise of the substrate 4 is higher than that of the conventional film forming method. The substrate 4 is relatively small (the temperature of the substrate 4 is about 50 ° C.), so that a film can be formed on a low heat-resistant substrate, which was impossible in the related art.

On the other hand, to give an example of similar characteristics of an amorphous hard carbon film obtained by a conventional continuous discharge RF plasma CVD method, first, CH ₄ (methane) is used as a raw material gas. In this example, the deposition rate was
The maximum was 1.3 μm / hr. The microhardness of the obtained amorphous hard carbon film was 30,000 MPa at the maximum.
The coefficient of friction is 0.08 in unlubricated atmosphere, and in lubricating oil,
0.12 was obtained. The wear depth of the film is less than 0.1 in an unlubricated atmosphere.
3 μm, 0.05 μm in lubricating oil. Further, the wear diameter of the mating material was 0.24 mm in a non-lubricated atmosphere and 0.26 mm in a lubricating oil. Furthermore, in the adhesion test, it was 37 N at the maximum with the so-called intermediate layer provided. The intermediate layer in this conventional example was formed of a DLC film containing silicon and nitrogen.

When the above-mentioned various characteristics of the amorphous hard carbon film according to the present invention are compared with those of the prior art, the film forming method according to the present invention (hereinafter referred to as “pulse plasma CVD method”) shows that the film forming rate is About twice as fast as the conventional method could be obtained. Regarding the hardness, the amorphous hard carbon film according to the present invention is lower than the conventional one, but the abrasion coefficient, the abrasion depth of the film and the abrasion depth of the mating material are improved as compared with the conventional one. It has become something. Regarding the adhesion, the amorphous hard carbon film according to the present invention shows a high adhesion of 50 N in a scratch test without providing an intermediate layer as in the related art.

Next, a comparison of the friction and wear characteristics between the amorphous hard carbon film according to the embodiment of the present invention and the film manufactured by the conventional method will be described with reference to FIG. The wear test performed to obtain the data in FIG. 4 was performed using a conventionally known and well-known ball-on-disk wear tester. As test conditions, a SUJ2 ball having a diameter of 6 mm was used as a mating material, a load of 10 N, a sliding speed of 25 mm / s (rotational speed of 159 rpm), and a sliding distance of 1 mm.
The conditions were 98 mm (21000 path), a sliding diameter of 3 mm, a humidity of 15 to 35%, and an atmospheric temperature of 25 ± 2 ° C.

First, in FIG. 4, "PW CVD" means film formation by the pulse plasma CVD method in the embodiment of the present invention as described above, and "CW CVD".
Is a conventional plasma CVD using a continuous wave high frequency signal.
It means film formation by the method. “FWD” is replaced by “Fi
Abbreviation for lm Wear Depth, which means the depth of friction of the film.
WSD ”is an abbreviation for“ Ball Wear Scar Diameter ”
It means the friction diameter generated in the ball of the mating material. In FIG. 4, the left vertical axis represents the magnitude of the friction coefficient, and the right vertical axis represents the magnitude of the friction coefficient.
The common vertical axis represents the size of each of "FWD" and "BWSD" described above. In the same figure, the abscissa indicates the raw material and the minute hardness of each film. In addition, on the right vertical axis, “FWD”
And "BWSD" are different from each other as shown. In the figure, the hatched histogram indicates the friction depth of the film, the white histogram indicates the wear diameter of the mating material, and the filled triangle indicates the friction coefficient. .

In this test example, the amorphous hard carbon film according to the present invention had a fine hardness of 13100 MPa. By comparing only the microhardness, it can be confirmed that a harder product is obtained by the conventional manufacturing method, but that the wear friction characteristics are equal to or higher than those of the conventional one.

Next, FIG. 5 shows the wear friction characteristics based on the results of the wear test performed in light oil, together with the wear friction characteristics of the film by the conventional film forming method. I do. The wear gas oil used here is ISO (T
he International Organization for Standardization)
“High Frequency Reciprocating Ri
g ”, the wear scar diameter after the test was 571 μm. The vertical and horizontal axes of the figure and the meanings of the respective abbreviations are the same as those in FIG. In the case of this light oil, as in the case of the above-mentioned wear friction characteristics in the atmosphere (see FIG. 4), by comparing only this minute hardness, the one obtained by the conventional production method can obtain a harder one. However, it can be confirmed that the abrasion friction characteristics show the same or higher characteristics as those of the conventional one.
The wear depth of the film is not inferior to the conventional one.

Next, the relationship between the pulse frequency, the film forming speed, and the minute hardness will be described with reference to FIG. First,
In the figure, the lower horizontal axis represents the pulse frequency (Pulse fr).
equency), the upper horizontal axis is the off time
Are respectively shown. Here, the pulse frequency is a value obtained by converting an application cycle of a high-frequency signal applied intermittently into a frequency, and f (MHz) = 10 ⁻⁶ / (a +
b) (a and b in FIG. 3).
reference). The pause time corresponds to a time b (see FIG. 3) during which the application of the high-frequency signal to the second electrode 3 is stopped. Further, the right vertical axis indicates minute hardness, and the left vertical axis indicates a film formation rate (Growth rate). In the upper left part of the figure, “QC ₆ H ₆
= 1 means that C ₆ H ₆ (benzene) is used as the raw material gas.
The notation “5.8 Pa” indicates the reaction pressure, and the notation “PW = 40 kW” indicates that the pulse RF power is 4
0 kW, the notation of “P _WID = 150 μs” is:
That the pulse width a (see FIG. 3) is 150 μsec,
The notation “T / S = 80 mm” means that the distance between the second electrode 3 and the first electrode 2 (see FIG. 1) is 80 mm.
It means each. The notation at the upper left of FIG. 6 is used in the same meaning in other drawings.

In the figure, a characteristic line represented by a two-dot chain line indicates a change in the film forming speed with respect to the pulse frequency (or the pause time). It can be seen that it increases with the increase. In other words, it can be confirmed that the deposition rate increases as the downtime decreases. In the figure, a characteristic line represented by a solid line indicates a change in microhardness with respect to the pulse frequency (or pause time). With this characteristic line, the microhardness tends to increase as the pulse frequency increases. It can be confirmed that there is. In other words, it can be confirmed that the microhardness tends to increase as the pause time becomes shorter. Incidentally, the conventional manufacturing method has a maximum of 28000M.
A fine hardness of Pa could be obtained.

Next, the relationship between the pulse power, the film forming speed and the minute hardness will be described with reference to FIG. First,
In FIG. 7, the horizontal axis represents the pulse power, and the pulse power mentioned here has the same meaning as the pulse RF power first mentioned as one of the film forming conditions in the embodiment of the present invention. The right vertical axis shows the microhardness, and the left vertical axis shows the film forming speed. The film formation conditions in this test example were set to a constant pulse frequency of 40 Hz.
This is the same as that described in FIG. 6 except that the pulse power is made variable. In the figure, a characteristic line represented by a two-dot chain line indicates a change in the film forming speed with respect to the pulse power. From this characteristic line, the film forming speed tends to increase with an increase in the pulse power. It can be almost confirmed. In the figure, the characteristic line represented by a solid line indicates a change in microhardness with respect to pulse power.From this characteristic line, microhardness tends to increase with an increase in pulse power. Almost can be confirmed. Note that a film could not be formed at a pulse power of 20 kW or less. According to this test example, it can be said that the high frequency power applied to the second electrode 3 is preferably 18 W / cm ² or more per unit area. The power value is a peak value.

Next, the relationship between the pulse width, the film forming speed, and the minute hardness will be described with reference to FIG. First, FIG.
, The horizontal axis indicates the pulse width. Also,
The right vertical axis shows the fine hardness, and the left vertical axis shows the film forming speed. The film forming conditions in this test example are the same as those described with reference to FIG. 6 except that the pulse frequency and the pulse width are variable. In the figure, the characteristic line represented by the two-dot chain line indicates the change in the film formation rate with respect to the change in the pulse width when the pulse frequency is set to 40 Hz, and the characteristic line represented by the one-dot chain line indicates that the pulse frequency is 20 Hz. 3 shows a change in the film forming rate with respect to a change in the pulse width in the case of. In the same figure, a characteristic line represented by a dotted line indicates a change in minute hardness with respect to a change in pulse width when the pulse frequency is 40 Hz, and a characteristic line represented by a solid line indicates a pulse frequency of 20 Hz. The change of the minute hardness with respect to the change of the pulse width in each case is shown. According to this test example, it can be confirmed that both the deposition rate and the microhardness increase with an increase in the pulse width between 50 and 150 μsec.

Next, the relationship between the pulse frequency and the friction coefficient, the wear depth of the film and the wear diameter will be described with reference to FIG. The characteristic line in FIG. 9 shows the result of evaluating the effect of the pulse frequency on the wear friction characteristics of the film by a ball-on-disk wear test in light oil. The conditions for the ball-on-disk wear test in light oil were first described in FIG.
Are the same as in the case of the test example shown in FIG. First, in FIG. 9, the horizontal axis indicates the pulse frequency. Also,
The right vertical axis is a common vertical axis representing the respective sizes of “FWWD” and “BWSD”, and the meaning of each abbreviation is described in FIG. Is the same as that described in the description. Further, the left vertical axis represents the magnitude of the friction coefficient. In the figure, the characteristic line represented by the two-dot chain line represents the change in the friction coefficient with respect to the frequency, and the characteristic line represented by the solid line represents the change in the wear depth of the film with respect to the pulse frequency. The characteristic lines indicate changes in the wear diameter of the counterpart material with respect to the pulse frequency.
According to this test example, the wear depth of the film (see the solid characteristic line) and the wear diameter of the mating material (see the dashed-dotted characteristic line)
Decreases as the pulse frequency increases, and it can be confirmed that the pulse frequency shows the best value at 40 Hz. Further, it can be confirmed that the friction coefficient increases with an increase in the pulse frequency.

Next, the relationship between the pulse width and the friction coefficient, the wear depth of the film, and the wear radius will be described with reference to FIG. The characteristic line in FIG. 10 shows the result of evaluating the effect of the pulse width on the wear friction characteristics of the film by a ball-on-disk wear test in light oil. The conditions of the ball-on-disk wear test in light oil are the same as those of the test example shown in FIG. First, in FIG. 10, the horizontal axis indicates the pulse width. In addition, the vertical axis on the right side is a common vertical axis representing the size of each of “FWWD” and “BWDSD”. 4 is the same as that described above. Further, the left vertical axis represents the magnitude of the friction coefficient.
In the upper right part of the figure, the notation “P _freq = 40 Hz” means that the pulse frequency is 40 Hz.

In the figure, the characteristic line represented by the two-dot chain line indicates the change in the coefficient of friction with respect to the pulse width, and the characteristic line represented by the solid line indicates the change in the wear depth of the film with respect to the pulse width.
The characteristic line represented by the dashed line indicates the change in the wear diameter of the mating material with respect to the pulse width.
Note that the film formation conditions were the same as before, and the pulse frequency of 40 Hz, which is the best condition, was used. According to this test example, the wear depth of the film (see the characteristic line of the solid line) and the wear radius of the counterpart material (see the characteristic line of the dashed line) decrease as the pulse width increases, and the best value is obtained at 150 μsec. It can be confirmed that it shows. Further, it can be confirmed that the coefficient of friction increases as the pulse width increases up to a pulse width of about 120 μsec, but thereafter gradually decreases as the pulse width increases.

Next, a method of supplying a reaction gas will be described. First, in the above-described formation of the amorphous hard carbon layer film in the embodiment of the present invention, it was assumed that the reaction gas was always supplied as in the related art, but this was supplied in a pulsed manner as follows. (Hereinafter, such a method of supplying the reaction gas is referred to as “pulse supply”). FIG. 2 shows an example of a device configuration required for pulse supply. First, this configuration example will be described. Note that the same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. Hereinafter, different points will be mainly described. In FIG. 2, a pulse synchronization control circuit 8 synchronizes with a pulse modulation operation of a pulse modulator 6 to control a first control valve 13 using a piezo valve.
This is for controlling the opening and closing operation of. That is, the first control valve 13 is controlled by the pulse synchronization control circuit 8.
As shown in FIG. 3C, the second electrode 3 is opened at a timing when a high-frequency signal is applied to the second electrode 3 in a pulsed manner.

Therefore, in such a configuration, the reaction gas is supplied into the vapor deposition chamber 1 immediately before the high-frequency signal is applied to the second electrode 3. By such a pulse supply of the reaction gas, during the discharge pause, that is, the second
During the period during which the application of the high-frequency signal to the electrode 3 is suspended (in other words, until the next high-frequency signal is applied),
Particles that have an adverse effect on film formation, called etching species, generated by a discharge reaction when a high-frequency signal is applied immediately before can be sufficiently exhausted to move to the next discharge state, and the film formation speed and hardness can be increased. And other properties of the film can be further improved.

This is presumed to be due to the following reasons.
Is done. The film grows when the source gas dissociates and separates in the plasma.
Of the particles that have been solved and become particles,
This is performed by vapor deposition on the substrate (substrate 4). original
When the feed gas is a hydrocarbon gas, for example, methane
In the case of CH₄→ CH ₃+ H → CH₂Like + 2H
It is considered that the dissociation proceeds by the reaction.
H₃And other particles contribute to film formation, and the decomposed hydrogen is etched away.
Generally speaking, it hinders film growth as a seeding species
Have been. By the way, the pulse plasma CV according to the present invention
In method D, particles dissociated by high-pressure plasma are
Film surface during film formation while retaining the collision energy of the potential difference
Impact, the effect of the etching species tends to appear significantly
No.

Therefore, it is considered that reducing the amount of etching species is very effective in improving the film formation rate. Further, in the pulsed plasma CVD method according to the present invention, since the discharge is repeated in a pulsed manner, both the deposition process of the film during the discharge and the deposition process by the particles having a long life called a so-called after-glow immediately after the discharge are performed. It is considered that the deposition of the film proceeds. Here, since the above-mentioned hydrogen atom has a sufficiently long life as compared with particles such as CH ₃ , it is expected that a soft layer containing a large amount of hydrogen is formed in the afterglow, which lowers the hardness of the film. It is possible that they have Therefore, the above-described pulse supply of the reaction gas can control the gas supply period, supply the fresh gas in a state where the particles dissociated in the first discharge are sufficiently exhausted, and perform the next discharge. Therefore, it is considered that the amount of generated hydrogen is suppressed in the vapor deposition process.

Although benzene is used as the reaction gas in the embodiment of the present invention, methane, acetylene, or the like may be used instead of benzene.

[0033]

As described above, in the amorphous hard carbon film according to the present invention, the wear amount of the film and the wear amount of the mating material in the wear friction test in light oil are reduced by the conventional film forming method. Thus, the adhesiveness is reduced, and the adhesiveness is higher than before without providing a so-called intermediate layer. In addition, it is possible to provide an amorphous hard carbon film in which the durability is improved by reducing the amount of wear and improving the adhesion. Further, according to the method for forming an amorphous hard carbon film according to the present invention, it is possible to obtain an amorphous hard carbon film capable of improving friction and wear characteristics and adhesion without providing an intermediate layer as in the related art. Since the film formation rate can be improved and the film formation speed is improved, a film formation method that is extremely cost-effective compared to the conventional method is provided. Further, according to the method for forming an amorphous hard carbon film according to the present invention, the method can be realized only by adding a pulse modulator to a conventional plasma CVD apparatus. It is possible to provide a film forming method having better film forming characteristics than in the past. Furthermore, according to the method for forming an amorphous hard carbon film according to the present invention, since the application of the high-frequency signal is performed in a pulsed manner, the temperature rise of the substrate can be reduced, and therefore, the formation on the low heat-resistant base material can be achieved. This has an effect of enabling a film.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration example of a pulse RF plasma CVD apparatus used for film formation by a pulse plasma CVD method according to the present invention.

FIG. 2 is a configuration diagram showing another configuration example of a pulse RF plasma CVD apparatus used for film formation by the pulse plasma CVD method according to the present invention.

FIG. 3 is a schematic diagram illustrating a state of application of a high-frequency signal in a pulse RF plasma CVD apparatus used for film formation by a pulse plasma CVD method according to the present invention.
FIG. 3A is a schematic diagram showing a change in power of a high-frequency signal applied to the second electrode, FIG. 3B is a schematic diagram showing a state of an electric field near the second electrode, and FIG. FIG. 3 is a schematic diagram showing a high-frequency signal applied to a second electrode.

FIG. 4 is a histogram showing wear friction characteristics obtained by a ball-on-disk wear friction test in the atmosphere together with similar wear friction characteristics of a film formed by a conventional film forming method.

FIG. 5 is a histogram showing wear friction characteristics by a ball-on-disk wear friction test in light oil together with similar wear friction characteristics of a film formed by a conventional film forming method.

FIG. 6 is a characteristic diagram showing a relationship between a pulse frequency, a film forming speed, and minute hardness.

FIG. 7 is a characteristic diagram showing a relationship among a pulse power, a film forming speed, and a minute hardness.

FIG. 8 is a characteristic diagram showing a relationship between a pulse width, a film forming speed, and minute hardness.

FIG. 9 is a characteristic diagram showing the effect of pulse frequency on wear friction characteristics in light oil.

FIG. 10 is a characteristic diagram showing the effect of pulse width on wear friction characteristics in light oil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vapor deposition chamber 2 ... 1st electrode 3 ... 2nd electrode 5 ... High frequency generator 6 ... Pulse modulator 7 ... Matching circuit 8 ... Pulse synchronous control circuit 9 ... 1st tank 13 ... 1st control valve

Claims (6)

[Claims] 1. A first and a second electrode are disposed in an evaporation chamber held in a vacuum so as to face each other, and a signal source for generating a high-frequency signal is connected to the second electrode. A high-frequency high-frequency signal is applied to the substrate, a reaction gas is introduced to cause a plasma reaction, and an amorphous hard carbon film is formed by vapor deposition on the substrate mounted on the second electrode surface. Applying the high-frequency signal between the electrodes in a pulsed manner at a predetermined repetition period, a predetermined pulse width, and a predetermined high-frequency power to obtain an amorphous hard carbon film. A method for forming a hard carbon film. 2. The method according to claim 1, wherein the predetermined repetition cycle is 40 Hz or more, the predetermined time is 150 μsec or more, and the predetermined high frequency power is 18 W / cm ² or more per unit area of the electrode. Item 3. A method for forming an amorphous hard carbon film according to Item 1. 3. The amorphous hard carbon film according to claim 1, wherein the reactive gas is supplied into the vapor deposition chamber in synchronization with the application timing of the pulsed high-frequency signal. Film formation method. 4. A first and second electrode are disposed in a vapor deposition chamber held in a vacuum so as to face each other, a signal source for generating a high-frequency signal is connected to the second electrode, and the second electrode is disposed between the two electrodes. To
A high-frequency signal is applied in a pulsed manner at a predetermined repetition period, a predetermined pulse width, and a predetermined high-frequency power, and a reaction gas is introduced to cause a plasma reaction, and a substrate mounted on the second electrode surface is formed. An amorphous hard carbon film formed on the substrate, wherein C ₆ H ₆ is used as the reaction gas. 5. A first and a second electrode are disposed in a vapor deposition chamber held in a vacuum so as to face each other, and a signal source for generating a high-frequency signal is connected to the second electrode. To
A high-frequency signal is applied in a pulsed manner at a predetermined repetition cycle, a predetermined pulse width, and a predetermined high-frequency power, and the reaction gas is introduced into the vapor deposition chamber in synchronization with the application timing of the pulsed high-frequency signal. An amorphous hard carbon film formed by introducing a plasma reaction to form a film on a substrate placed on the second electrode surface, wherein C ₆ H ₆ is used as the reaction gas. An amorphous hard carbon film characterized by the following. 6. The predetermined repetition cycle is 40 Hz or more, the predetermined time is 150 μsec or more, and the predetermined high frequency power is 18 W / cm ² or more per unit area of the electrode. Item 6. The amorphous hard carbon film according to item 4 or 5.