JPS63221840A - Manufacture of amorphous hydrogenated carbon membranes - Google Patents

Abstract

PURPOSE:To enable formation of high-performance membranes at low temperatures near a room temperature level and at high speed by polymerizing specific hydrocarbon organic compounds using a low-frequency plasma discharge decomposition method under vacuum. CONSTITUTION:In the first-fifth tanks 6-10 of a capacitor coupling-type plasma CVD as a membrane manufacturing device, hydrocarbon organic compounds such as butadiene having an adiabatic first ionization potential of 8.5-10eV and carrier gases such as H2, He and Ar are hermetically sealed with other additive compounds such as halogen atoms. A reaction chamber 23 is kept under a constant vacuum condition and an electric power of 30-1kw at low frequency of 10-1,000kHz is applied to an electrode plate 22 from a low-frequency power source 26 to generate a plasma discharge between both electrodes 22, 25. Subsequently, amorphous hydrogenated carbon membranes of a desired thickness are formed on a preheated substrate 24 while compound vapors are properly supplied from the tanks.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing an amorphous hydrogenated carbon film that can be formed at around room temperature and at a high film formation rate.

Prior Art and Problems Organic plasma polymerized films can be prepared from all kinds of organic compound gases such as ethylene gas, benzene, and aromatic silanes (e.g., N.T., Be1).
l), M, 5hen et al., [Journal of Applied Polymer Science J (Jou
rnal of Applied Polymer 5
science), Vol. 17, pp. 885-892 (197
3 years) etc.) are known.

However, plasma polymerized films vary greatly in film formability, film properties, etc. depending on the type of raw material gas, manufacturing conditions, etc. Generally, in order to obtain a film with high hardness, scratch resistance, and excellent environmental resistance by plasma polymerizing hydrocarbon-based organic compounds, it is necessary to heat the substrate material to a high temperature and perform the polymerization at a high frequency of around 13.56 MHz. there were.

Therefore, the substrate materials that can be coated with plasma polymerized films are naturally limited, and hydrocarbon-based organic compounds are recommended for articles made of materials that soften or deform at high temperatures, or for various devices that deteriorate their characteristics. Application of plasma polymerization method was difficult.

Problems to be Solved by the Invention The inventors of the present invention have repeatedly studied various plasma polymerization methods, and have discovered that some types of hydrocarbons can form plasma-polymerized films at around room temperature.

That is, an object of the present invention is to provide a method for producing an amorphous hydrogenated carbon film that can form a hydrocarbon-based organic compound by plasma polymerization even at a low temperature around room temperature.

Means for Solving the Problems The present invention has a boiling point with an adiabatic first ionization potential of 8.5.
to 10. The present invention relates to a method for producing an amorphous hydrogenated carbon film, which is characterized by polymerizing a hydrocarbon-based organic compound that is OeV using a low-frequency plasma discharge decomposition method with a frequency of 10 to 1000 KHz in vacuum.

In this specification, the adiabatic first ionization potential refers to the ability to ionize an ion to its lowest vibrational state by separating the single electron with the highest energy from a molecule in the ground state to infinity. It refers to a numerical value expressing the required energy in units of electron volts (eV), and specifically refers to the value measured by photoelectron spectroscopy.

Adiabatic first ionization potential is 8.5-10°OeV
Examples of hydrocarbon organic compounds include cyclohexane (9,89eV), propylene (9,74eV), arene (9,69eV), 1-buty:, z (9,59eV)
, cyclobutene (9,43eV), benzene (9,24
eV), 2-methylpropene (9,21eV), butadiene (9,06eV), bicyclopropyl (9,04eV)
■), cyclopentene (9,01), cycloheptene (
8,87eV), toluene (8,82eV), cyclooctane (8,82eV), phenylacetylene (8°7
5 eV), 2-methyl-2-butene (8,72 eV),
Examples include 2-phenylbutadiene (8,57eV) and cyclopentadiene (8,57eV).

The hydrocarbon organic compounds used in the present invention may be used alone or in combination. When using a compound with unsaturated bonds, it cleaves during plasma polymerization and has the function of forming a crosslinked structure between molecules, so it is difficult to peel off from the substrate compared to compounds without unsaturated bonds. A hard film tends to be formed. Moreover, the hydrocarbon-based organic compound applicable to the present invention may further contain a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, and the like.

As a compound containing a halogen atom, l-chloro-1
, 2,2-trifluoroethylene (9,84eV), cyclopropyl bromide (9,32eV), ■, 1°4.4-
Tetrafluorobutadiene (8,98eV), 1.1.
1-trifluoro-2-iodoethane (9°99eV)
etc. are exemplified.

As a compound containing an oxygen atom, acetone (9°72e
V), ethyl methyl ketone (9,51 eV), diethyl ether (9,61 eV), and the like.

As a compound containing a nitrogen atom, acetamide (9,8
0eV), isopropylamine (8,86eV), ethylamine (9,19eV), diethylamine (8°51
eV), pyridine (9,28 eV), and the like.

As a compound containing a sulfur atom, thiophene (8,8
7 eV), benzothiazole (8,72 eV), and the like.

These compounds are used alone or in combination with planar hydrocarbon organic compounds, and by avoiding the inclusion of halogen atoms in the amorphous hydrogenated carbon film of the present invention, water repellency, abrasion resistance, and transparency are achieved. The optical property is improved, and especially in the case of fluorine, the refractive index is reduced, and an antireflection effect can be achieved.

Furthermore, other hydrocarbon compounds such as methane, ethane,
A mixture of ethylene, acetylene, propane, etc. may be used.

When such compounds are used, plasma polymerization can be carried out at low temperatures (room temperature to 1
00°C).

Therefore, it is possible to coat not only various heat-resistant ceramic products and metal products, but also resins such as polymethyl methacrylate that have poor heat resistance, and various devices that are susceptible to property deterioration due to heat, making the present invention versatile. can be expanded to.

In the present invention, the adiabatic first ionization energy is 8.5e.
If a hydrocarbon-based organic compound smaller than V is used, film-forming properties will decrease, the degree of cross-linking between hydrocarbon-based organic compounds will decrease, and oily substances will be formed, resulting in contamination of the substrate and the inside of the Pelger reaction chamber. Problems also arise.

When a hydrocarbon-based organic compound with an adiabatic first ionization energy greater than io, 0 eV is used, the probability that the polymerization reaction will proceed in the gas phase at room temperature increases, and the formation of a powdery polymer is promoted. However, since a polymer film is not formed on the substrate, film forming properties are deteriorated. There is also the problem that the powdered polymer contaminates the substrate or the interior of the reaction chamber.

In plasma polymerization, molecules in the gas phase are decomposed by discharge under reduced pressure, and active neutral species or charged electrodes contained in the generated plasma atmosphere are induced onto a substrate by diffusion, electric force, magnetic force, etc. The solid phase is deposited by the recombination reaction described above, which is generated from a so-called glow discharge plasma polymerization reaction, and is formed through a plasma state generated by a plasma method using a low frequency of 10 to 1000 KHz. A planar hydrocarbon-based organic compound is formed into a film at a low temperature near room temperature and at a high speed.

Even if a high frequency of 1000 KHz or more is used for plasma generation, the number of radical species or ion species of compounds generated by the plasma that reach the substrate decreases, the deposition rate decreases, and polymerization in the gas phase progresses accordingly. As a result, oily and powdered polymers are likely to be formed. However, if it is possible to maintain the substrate temperature at a high temperature, butadiene or the like can be formed into a film by plasma polymerization at a frequency of 100 OKI-Iz or more, and the above-mentioned problem does not occur.

Furthermore, when polymerization is performed by generating plasma at a frequency of 10 KHz or less, ion damage increases compared to the increase in the number of times the generated radical species or ion species reach the substrate, resulting in brittleness and A rough film with poor adhesion to the substrate is formed.

The amorphous hydrogenated carbon film of the present invention can be produced by combining ionization deposition method, ion beam deposition method, vacuum deposition method, sputtering method, etc. within the scope of the purpose of the present invention, in addition to the low-frequency plasma method. It's okay.

The amorphous carbon film formed according to the present invention has a hydrogen content of 10 to 60 atomic% based on all constituent atoms, and has the following characteristics.

(a) High hardness. A pencil hardness of 3H or higher according to the JIS-5400 standard can be easily obtained.

(b) It can be coated on all kinds of base materials and devices and has excellent adhesion.

(c) It has excellent solvent resistance and is insoluble in various solvents, acids, alkalis, etc.

(d) It is deposited and formed isotropically and uniformly.

There is no shadow seen with vapor deposition, etc.

(e) It has excellent environmental stability, and the properties of the polymeric film are
Resistant to change over time.

(f) It has excellent thermal conductivity, so even if it is coated on a heating element such as an IC, no heat will accumulate inside it.

(g) It has excellent light transmittance, and a film with a thickness of 0.2 μm can transmit 90% or more of visible light.

(h) Excellent wear resistance. Although it has high hardness, it has a low friction coefficient and has excellent wear resistance.

(W) The refractive index is about 1.3 to 1.6.

(nu) Ionization potential is approximately 5.0 to 6. It is OeV.

FIGS. 1 and 2 show a capacitively coupled plasma CVD apparatus, which is an apparatus for producing an amorphous hydrogenated carbon film according to the present invention. FIG. 1 shows a parallel plate plasma CVD apparatus, and FIG. 2 shows a cylindrical plasma CVD apparatus.

Both devices have electrode plates (22) and (25) in FIG.
) and the substrate (24) are of a flat plate type, whereas the electrode plate (30) and the substrate (31) in FIG. 2 are of a cylindrical type. Further, in the present invention, it can also be produced using a separate inductively coupled plasma CVD apparatus. The method for producing an amorphous hydrogenated carbon film of the present invention will be explained using a parallel plate plasma CVD apparatus (FIG. 1) as an example. In the figure, (6) to (10) have first ionization potentials of 8.5 and 10. The first to fifth tanks are sealed with OeV hydrocarbon organic compounds, carrier gases such as Hl, He, Ar, and other additive compound gases. , ) ~ (15)
and mass flow controllers (16) to (20). These gases are sent into the reaction chamber (23) via the main pipe (21).

A low frequency power source (2) is connected to the reaction chamber (23) via a capacitor.
A flat earth electrode plate (25), which is electrically grounded and on which a flat substrate (24), etc. is placed, is arranged opposite to the flat electrode plate (22) connected to the electrode plate (22). There is. Further, the flat electrode plate (22) is connected to a DC voltage source (28) via a coil (27), so that a DC bias voltage is additionally applied in addition to the power applied from the low frequency power source (26). It has become. Also electrode plate (25)
The substrate (24) and the like placed thereon are heated, if necessary, by a heating means (not shown) to, for example, room temperature to lOO<0>C.

In the above configuration, for example, when butadiene is plasma-polymerized on a polymethyl methacrylate plate to produce an amorphous hydrogenated carbon film, the reaction chamber (23) is brought into a constant vacuum state and then the Butadiene gas is supplied from the first tank (6), and H gas is supplied as a carrier gas from the second tank (7). On the other hand, a power of 30 watts to 1 kv is applied to the flat electrode plate (22) from the low frequency power source (26) to generate a plasma discharge between the two electrode plates to form a desired thickness on the preheated substrate (24). Form an amorphous hydrogenated carbon film (2).

Furthermore, other atoms, such as halogen atoms such as fluorine and chlorine, V group elements such as nitrogen, phosphorus, and arsenic, or group I elements such as boron, aluminum, gallium, and indium, may be added to the amorphous hydrogenated carbon film. In order to achieve this, vapors of compounds containing these elements may be appropriately introduced from a tank into the reaction chamber (23) and plasma polymerized together with hydrocarbon-based organic compounds. , refractive index, polarity, etc. can be adjusted. Other atoms can also be added by bombarding the film with the above gas after film formation.

The capacitively coupled plasma CVD apparatus shown in Figure 3 uses a monomer that is liquid at room temperature, such as toluene, as the hydrocarbon-based organic compound, so it is constant temperature! While heating the hydrocarbon organic compound (33) by (32),
The pipe (34) connected to the reaction chamber is also heated and the hydrocarbon-based organic compound is introduced into the reaction chamber (23) as vapor. The other configurations are the same as in FIG. 1.

The amorphous hydrogenated carbon film of the present invention includes the types of starting material gas and other additive gases, the ratio of material gas to diluent gas (H7, inert gas), discharge power, pressure, substrate temperature, DC bias voltage, and annealing temperature. By selecting manufacturing conditions such as , discharge frequency, etc., various film characteristics can be adjusted. Therefore, the above conditions should be appropriately set depending on the object to which the amorphous hydrogenated carbon film of the present invention is applied so as to obtain desired film characteristics.

For example, if you want to form the carbon film with high hardness as a film characteristic, you can change the film forming conditions, such as increasing the low frequency power, lowering the power frequency, or increasing the substrate temperature within the scope of the purpose of the present invention. is valid.

If it is desired to increase the translucency of the film, the operation opposite to the above conditions is effective.

When wear resistance is required, it is effective to include halogen atoms, particularly fluorine atoms, in the amorphous carbon film.

As the fluorine-containing compound, fluorine gas, methyl fluoride gas, tetrafluoromethane gas, fluorinated ethylene gas, fluorinated ethylidene gas, perfluoropropane gas, etc. can be used. It should be noted that when fluorine atoms are contained, the film tends to lose its transparency.

If it is desired to obtain an amorphous hydrogenated carbon film with a high refractive index, atoms of silicon, germanium, etc. are added to the film.

As the silicon source, SiH, 5ttHa gas, etc. may be used; as the germanium source, GeH4, GetHs gas, etc. may be used.

If polarity control regarding conductivity is required,
It is effective to add atoms of the group or group II. The addition of group (1) elements and group (2) elements allows the polarity of the film to be adjusted to p-type and n-type, respectively.

Examples of group III elements include Bs AQSG as I n, and examples of compounds containing B include B (OC2Hs:
Examples include h, BtHe, BCQs, B B r 3, BP, and the like.

AQ (Of C3H?)3 is a compound containing AQ.
, (CHa)3A(21(CtHs)3AI21(i
C4Ha)sA12-AQCQs and the like are exemplified.

A compound containing Ga is Ga (Oi C3H?)!
, (CH,)3Ga, (CtHs)3GaSGaCQs
, G aB r*, etc.

A compound containing In is In (Oi C3H?)
3, (ctHs)aIn, etc.

Examples of group V elements include P, As, Sb, etc., and compounds containing P include P O(OCH3)3, (C.

H5) 3P, PHs, PF, , POCQs, etc.; Compounds containing AS include As Hs, AsCQ3, AsBr*
etc.; 5b(OC*Hs)s, 5 as a compound containing Sb
Examples include bC23 and 5bH5.

The content of the above-mentioned halogen atoms, group II atoms, group II atoms, etc. should be appropriately selected depending on the use of the amorphous hydrogenated carbon membrane.
23) This can be done by controlling the flow rate inward. Furthermore, the content of atoms in the carbon film can be measured by infrared absorption spectroscopy, 'H-NMR, 13C-NMR, organic elemental analysis, Auger spectroscopy, etc.

Using various substrates shown in (a) to (p) below, film formation was attempted under the five conditions shown in Table 1 (Examples 1 to 5).

For comparison, the results of film formation under conditions outside the scope of the present invention are also shown in Table 1 (Comparative Examples 1 to 5).

(Substrate type) (a) Glass (Corning #7059) (b)
Silicon wafer (C) Aluminum plate (A6063) (d) Aluminum plate (A5386) (e) Stainless steel plate (f) Aluminum evaporated glass plate (g) Chrome sputtered glass plate (h) Gold evaporated glass plate (i) Tungsten wire ( D Copper plate (k) A s t S e3 vapor deposited aluminum plate ((2)
GD a-9i deposited aluminum plate (m) Polyester resin (V-200 manufactured by Toyobo Co., Ltd.) coated aluminum plate (n) Polycarbonate resin (manufactured by Ondai Kasei Co., Ltd. -1
300) Coated aluminum plate (0) Methyl methacrylate PMMA (BR-85 made by Mitsubishi Rayon Co., Ltd.) coated aluminum plate (p) Boria arylate (U-400 made by Unitika Co., Ltd.)
0) Coated aluminum plate (film formation) In the glow discharge decomposition apparatus shown in FIG. (11) to (12)) are released, and the raw material gas is transferred from the first tank (6) to the second tank (
7) H2 gas from mass flow controller (16) ~
(17), the amount of gas was adjusted to be as shown in Table 1 and flowed into the reaction chamber (23).

After each flow rate became stable, the internal pressure of the reaction chamber (23) was adjusted to the value shown in Table 1. On the other hand, the board (24
), the above (a) to (p) were used, and Table 1
After preheating to the temperature shown in Table 1, and with each gas flow rate stabilized and the internal pressure stabilized, the low frequency power supply (26) was turned on and the flat electrode plate (22) was heated to the frequency shown in Table 1. Plasma polymerization was performed for the time shown in Table 1 by applying electric power to form an amorphous hydrogenated carbon film on the substrate (24).

In Table 1, the film formability on various substrates was evaluated by ○ and X. ○ is 1 in the JIS-5400 basic test
A score of 0 indicates that the film has excellent adhesion, while an x indicates that it is difficult to form a film due to oily state, powdery state, or peeling from the substrate in the above test.

Effects of the Invention The method for producing an amorphous hydrogenated carbon film of the present invention can be carried out at low temperatures (room temperature to
It can be formed into a film at a temperature of 100° C.) and can be applied to articles made of materials that deform or soften at high temperatures, so it has a wide range of applications.

According to the manufacturing method of the present invention, the film can be deposited at a high rate and a large area can be formed.

The amorphous hydrogenated carbon film obtained by the present invention has excellent hardness and environmental resistance, and can be imparted with various properties by adding other components as desired.

[Brief explanation of drawings]

1 and 3 show one of the apparatuses for carrying out the present invention.
It is a figure which shows an example. (6) to (10)...Tank, (11) to (15).
...Control valves (16) to (20)...Mass flow controller, (21)...Main pipe, (22)...
・Flat type electrode plate, (23)...reaction chamber, (24
)... Flat board, (25)... Flat ground electrode plate, (26)... Low frequency power supply, (27)... Coil,
(28)...DC voltage source, (29)...Vacuum pump, (30)...Cylindrical electrode plate, (31)...Cylindrical substrate, (32)...Thermostatic chamber, (33)... )...Hydrocarbon organic compound (34)...Connecting pipe, (40)...Vacuum container, (41)...Power source, (42)...Electrode support rod, (43), ( 44)...Carbon electrode, (45)...Substrate holding stand, (46)...AQ substrate.

Claims (1)

[Claims] 1. Adiabatic first ionization potential is 8.5 to 10.
A hydrocarbon-based organic compound with a voltage of 0 eV is heated to a frequency of 10 in vacuum.
1. A method for producing an amorphous hydrogenated carbon film, characterized in that polymerization is performed using a low frequency plasma discharge decomposition method of 1000 KHz to 1000 KHz.