JPS6383270A - Production of diamond-like carbon film - Google Patents

Abstract

PURPOSE:To form a superior-quality diamond-like carbon film which has high hardness and is excellent in insulating properties on an Si wafer by forming the activated species of carbon-contg. gas mixed with the activated species of gaseous H2 accelerated with an electric field in the vicinity of the base late of the Si wafer incorporated in a vacuum tank. CONSTITUTION:A base plate 12 of an Si wafer is fitted on a holder 13 thereof in a vacuum tank 1 and heated at 300-800 deg.C with a heater 14. Gaseous H2 is fed to a high-frequency coil 9 through an introduction pipe 7 from a gaseous H2 cylinder 6. Plasma discharge is caused between the high-frequency coil 9 and the holder 13 with a high-frequncy electric source 11 to form the activated species of gaseous H2 and also carbon-contg. gas such as CH4 is discharged through an introduction port 8 from a cylinder 4 and jetted on the base plate 12 together with the activated species of gaseous hydrogen. A diamond-like carbon film which has extremely high hardness and extremely small electric conductivity not more than 10<-11>OMEGA<-1>cm<-1> and is used for decoration, a workpiece and passivation of a semiconductor can be formed on the base plate 12 with excellent productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a tire cent-shaped carbon film that is used as a decorative coating, a coating for workpieces, and a coating for electronic devices.

[Prior art] One of the methods for producing Tiasene 1-like carbon membranes is a low-pressure synthesis method, and methods that have been proposed so far include thermal CVD, plasma CVD (pCVD), and ion Beam method (IB method), ion plate ink method (IP method)
etc.

These methods include introducing a carbon-containing gas into a film formation space using hydrogen gas as a carrier gas, and forming a film by thermal decomposition on a substrate heated to about 600 to 1300°C (thermal CVD method), or the above-mentioned method. The introduced gas is brought into a plasma state in the film forming space to generate carbon-containing active species (C), and the active species or other active species derived from the active species are caused to collide with the surface of the substrate. To form a film (PCVD method), active species of ionized carbon or carbon-containing gas are generated, and the active species are accelerated and collided with the surface of the substrate using an electric field to form a film (PCVD method).
IB Law and IP Law).

In addition to this, there is a method of manufacturing a tire-cent shaped carbon film by electron cyclotron resonance (ECR). For example, E
A method for producing a diamond-like carbon film by applying an accelerating voltage to the CR plasma outlet to draw out ions (Unexamined Japanese Patent Publication No. 6O
-103099), method for producing a tire tent-shaped carbon film in an ECR plasma generation chamber (JP 60-103098)
, a method of intermittently directing charged particles to a deposition chamber (48, 60-195092, etc. is known).

[Problems to be Solved] However, in the conventional method described above, carbon-containing gas and hydrogen gas are introduced into the film forming space in a mixed state, and these gases are simultaneously activated and decomposed in the mixed state. Active species generated from hydrogen gas (hereinafter referred to as "active species (H)", meaning excited molecules, ion species, and radical species).

) and carbon-containing active species (hereinafter referred to as "active species (C)", meaning excited molecules, ionic species, and radical species) occur simultaneously, and the production rate and activity of each active species It is not possible to independently control the degree of oxidation, and there are considerable restrictions on the degree of freedom of membrane installation needles.

In the case of the thermal CVD method and PCVD method, the degree of vacuum during film formation is relatively low, and in the case of the IB method and IP method, the distance from the position where active species are generated to the substrate surface for film formation is Because of the long distance between the two, the generated carbon-containing active species (C) collide with each other before reaching the substrate surface, forming a diamond-like carbon film (mainly containing sp'-structured carbon). In the formation of a carbon film), undesirable active species are generated, and this causes the formation of a carbon film (high electrical conductivity, low Vickers hardness) that mainly contains SP2 structure or SP structure carbon. easy to be Also, depending on the type of raw material gas, carbon-containing active species with a large molecular weight are generated, and these active species collide with the film surface formed on the film-forming substrate -1-, causing etching and sputtering of the film surface. There is also the problem that the film formation rate is suppressed because of this.

In addition, carbon-containing active species (C
) and film formation in the same space, the inner wall surface of the vacuum deposition chamber that forms the space may become contaminated with adhesion of soot, etc., and this contamination may cause the desired film properties to deteriorate. Even if it is not possible to form a film with a 100% active species, or if the active species generation chamber and film formation chamber are separated from each other as in the IB method, contamination of the inner wall surface of the active species generation chamber is unavoidable. . For this reason, it is necessary to clean the inner wall surface of the vacuum deposition apparatus every time a film is formed, which poses problems in terms of productivity and mass production.

The ECR method also had problems with point 11.

[Purpose] The present invention has been made in view of the above points, and its main purpose is to propose a method for manufacturing a diamond-like carbon film that can solve the conventional problems.

Another feature of the present invention is to suppress the content of carbon in the SP2 structure and sp structure, and to produce a carbon film containing mainly carbon in the sp' structure, with extremely low electrical conductivity and high Vickers hardness. The object of the present invention is to propose a method for manufacturing a diamond-like carbon film that can be easily produced.

Still another object of the present invention is to propose a method for manufacturing a diamond-like carbon film with excellent productivity and mass production.

[Means for Solving the Problems] The object of the present invention is to
This is achieved by introducing active species generated from hydrogen by accelerating an electric field through the first introduction means and introducing a carbon-containing gas through the second introduction means during the film formation.

[Function] According to the method for producing a diamond-like carbon film of the present invention described above, the content of carbon in the SP2 structure and the SP structure is extremely small compared to the conventional method, and the carbon film mainly contains carbon in the SP'3 structure. can be produced with higher efficiency and better reproducibility than in the past, and there is no need to clean the vacuum deposition apparatus itself as in the past.

Furthermore, since the film produced mainly contains carbon with an SP3 structure, it is comparable in hardness to diamond-like carbon films produced by conventional methods, and is also electrically resistant. Good quality and electrical conductivity of 10
-"Ω-1cm"' Since it is extremely small, less than 1, it is suitable for decorative coatings, coatings for workpieces, semiconductor passivation films, and even films constituting new electronic devices.

The present invention will be explained in detail below.

The method for producing a diamond-like carbon film according to the present invention is characterized by the above-mentioned points, and more specifically, as a preferred embodiment, the active species (H) generated from hydrogen gas is
It is generated by means such as electrical discharge, microbar discharge, DC discharge, arc discharge, and hot filament. The active species (H) are accelerated by the electric field and move toward the substrate surface. Separately from this, a carbon-containing gas is introduced into the film forming chamber through an inlet of another introduction means. As a result, the respective components are mixed near the surface of the substrate, and a tire-like carbon film is formed on the surface of the substrate.

At that time, the mean free path (see) of the carbon-containing active species (C) is 1 between the inlet of the carbon-containing gas introduction means and the substrate.
The pressure in the vacuum deposition chamber during film formation is adjusted so that the distance between This pressure adjustment is carried out by controlling the introduced active species (H), the respective flow rates of the carbon-containing raw material gas, the gas loss rate of the gas loss system, and the like.

In the present invention, the substrate for film formation or the intermediate electrode may be
The active species (H) are accelerated by applying a negative electric field of about 00V to 15KV. For the intermediate electrode, a wire mesh, a link, a straight metal, or the like can be used. In order to make the film thickness uniform, it is desirable to use 11 fine wire meshes. The material used is stainless steel, tungsten, tantalum nana, etc. Substrate temperature ranges from room temperature to 1000°C
range is desirable. In particular, the temperature is preferably 300 to 800°C. By doing this, it is possible to stabilize the plasma and form a uniform film. Further, by pulsing the carbon-containing gas, sp and sp2 hybrid carbon in the film can be removed by hydrogen plasma. The carbon-containing gas used in the present invention is CH4, C2Hs, C
Chain and alicyclic hydrocarbons such as 3Ha, C6HI3, C
Alcohols such as H2OH and C2H50H, CF4. C
Halides such as 2F6, aldehydes, ketones, organometallic compounds, and the like can be used alone or in combination of two or more.

FIG. 1 and FIG. 2 show an example of an apparatus used to carry out the present invention. Figure 1 shows an apparatus in which a voltage is applied to the substrate, and Figure 2 shows a device in which a stainless steel wire mesh is inserted between the substrate and the hydrogen activation source.
This is a device in which a voltage is applied. In both FIG. 1 and FIG. 2, hydrogen is activated by turning it into plasma using a 13.56 MHz high frequency coil. In the figure, 1.16 is a vacuum chamber, and the main bag 2.17 is connected to a vacuum pump. 3.5.18.20 are gas valves used for film formation. 4.19 is a carbon-containing gas cylinder, and 6.21 is a hydrogen gas cylinder. 7.22 is hydrogen gas inlet, 8
．． 23 is a carbon-containing gas inlet. 11.26 is 13
．． 9.24 is high frequency coil 1 with 56MHz high frequency power supply
High frequency matching is done with O225. 12.2
7 is a substrate, 13.28 is a substrate holder, 14.29 is a heater for heating the substrate, 15.31 is a DC power supply for voltage application,
30 is a wire mesh intermediate electrode.

Specific examples of the present invention are shown below.

[Example 1] A circular silicon wafer having a size of 1 inch was attached to a substrate holder of the apparatus shown in FIG. 1 as a substrate for film formation, and film formation was performed under the experimental conditions shown in Table 1. Methane was used as the carbon-containing gas, and the distance between the substrate and the methane gas inlet was 1.5 cm.
And so.

Table 1 Approximately 9 gm of carbon film was deposited on the substrate in a 10 hour deposition time. When this carbon film was analyzed by X-ray diffraction, peaks identified as (111) and (220) planes of diamond were confirmed.

Also, the Vickers hardness is 4000kg/mm2. The electrical conductivity was IQ-+1Ω-'cm-'.

[Comparative Example 1] Using the same apparatus as in Example 1, methane gas was mixed with hydrogen gas and introduced from the gas introduction lower, and the other conditions were as in Example 1.
Film formation was carried out under the same conditions as (at this time, the gas inlet 8 was removed).

Approximately 8 pLm of carbon film was deposited on the substrate in 10 hours of deposition. When this carbon film was analyzed by X-ray diffraction, peaks associated with the (111) and (220) planes of diamond were not confirmed, and the Vickers hardness was 2500 kg.
/ m m', and the electrical conductivity is 1O-6Ω-'
cm-'.

[Comparative Example 2] Using the same apparatus as in Example 1, the distance between the substrate and the carbon gas inlet was set to 8 cm, which was longer than the mean free path of the carbon-containing gas active species. Table 2 shows the experimental conditions.

Table 2 A carbon film of about 8 #Lm was deposited on the substrate after 10 hours of film formation. When this carbon film was analyzed by X-ray diffraction, peaks associated with the (111) and (220) planes of diamond could not be confirmed, and the Vickers hardness was 2800 k.
g/m m2, and the electrical conductivity is 5xlO-
It became 6Ω-'Cm-'.

[Example 2] A 1-inch circular silicon ueno Methane was used as the carbon-containing gas, and the distance between the substrate and the methane gas inlet was 1.5 cm, and the distance between the intermediate electrode and the substrate was 3.5 cm.

Table 3 Approximately 12 gm of carbon film was deposited on the substrate in 10 hours of deposition. When this carbon film was analyzed by X-ray diffraction, peaks corresponding to the (111) and (220) planes of diamond were confirmed. The /2° Vickers hardness was 4200 kg/mm 2 and the electrical conductivity was IQ-10Ω-'cm-'.

(Effects of the Invention) As explained above, by mixing carbon-containing gas with active hydrogen gas species accelerated by an electric field near the substrate to generate active species of carbon-containing gas, the carbon-containing gas has high hardness and good insulation properties. We were able to create a high quality diamond-like carbon film. Specifically, by separating the hydrogen gas activation part and the carbon-containing gas introduction part, etching of the film does not occur, the film formation rate increases, and the generation of carbon with an sp2 hybrid orbital is suppressed. Diamond-like carbon is deposited on the substrate.

Furthermore, by arranging the carbon-containing gas inlet near the substrate, the probability of existence of carbon-containing active species increases, and high-quality diamond-like carbon is deposited on the substrate.

[Brief explanation of the drawing]

FIGS. 1 and 2 show an apparatus for manufacturing a diamond-like carbon film according to the present invention. 1.16 Reaction chamber 4.19 Carbon-containing gas 6.21 Hydrogen gas 7.22 Hydrogen gas inlet 8.23 Carbon-containing gas inlet 9.24 High-frequency coil 11.26 High-frequency power supply 12.27 Substrate 14.28 Substrate holder 15.31 DC power supply 30 intermediate electrode

Claims (1)

[Claims] An active species generated from hydrogen is introduced into a film forming space in which a film forming substrate is arranged by being accelerated by an electric field through a first introducing means, and a carbon-containing gas is introduced through a second introducing means. A method for producing a diamond-like carbon film, characterized by forming a film.