JPS63221841A - Manufacture of amorphous hydrogenated carbon membranes - Google Patents

Abstract

PURPOSE:To enable even resins having inferior heat resistance at low temperatures near room temperatures to be coated with membranes by polymerizing specific hydrocarbon organic compounds by low-frequency plasma method. CONSTITUTION:Hydrocarbon organic compounds used are compounds having an energy gap of 95-11eV between the highest molecular orbit to be occupied and the lowest molecular orbit. For instance, cisbutadiene, transbutadiene, allene, etc. are used. When manufacturing the membrane, first a reactor chamber 23 is set to a constant vacuum state in a glow discharge decomposition device, and a stock gas is introduced into the reactor chamber 23 from the first-fifth tanks 6-10 with a carrier gas while adjusting the gas amount. When the internal pressure is stable, a low-frequency power supply 26 is turned ON to allow low-frequency plasma polymerization at frequencies of 10-100kHz. Thus amorphous hydrogenated carbon membranes are formed on substrates 24 such as polymethylmethacrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION 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).
1), M, 5hen et al., Journal of Applied Polymer Science J
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 provides a hydrocarbon-based organic compound in which the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (L, UMO) is 9.5 to 11 eV. The present invention relates to a method for producing an amorphous hydrogenated carbon film, which comprises polymerizing in vacuum using a low frequency plasma discharge decomposition method at a frequency of 10 to 1000 KH2.

Electrons may be present within the molecule. There are various orbitals, but the highest occupied molecular orbital (HOMO) is the one with the highest energy among the orbitals containing electrons (Hi
ghost 0ccupied Mo1ecularO
The lowest unoccupied molecular orbital (LUMO) is the lowest energy orbital that does not contain an electron (1, lowest unoccupied molecular orbital).
ular 0rbftal).

In the present invention, the energy gap between the HOMO and LUMO is 9.5 to 11 eV, preferably 9°7 to IO.
,7 eV, more preferably 9.8 to 10°5 eV.

The energy gap between rt OMO and LUMO is 9
If a hydrocarbon-based organic compound with a voltage smaller than 5 cV is used, it becomes difficult to achieve plasma polymerization at low temperatures.

In other words, the energy gap between HOMO and LUMO is 9
, 5 eV tend to be easily liquefied at room temperature, so when performing plasma polymerization, it is necessary to vaporize and maintain that state. It is necessary to equip a heater for this purpose and a heater to prevent condensation inside the piping and the reaction chamber, which leads to the complexity of the apparatus. Furthermore, even if the organic compound is maintained at the lowest temperature required for vaporization, decomposition by plasma discharge cannot be achieved sufficiently, and the degree of crosslinking between hydrocarbon-based organic compounds becomes low, resulting in the formation of an oily substance. There also arises the problem that the substrate and the inside of the Pelger reaction chamber are contaminated.

When a hydrocarbon-based organic compound with an energy gap between HOMO and LUMO of more than 11 eV is used, the probability that the polymerization reaction will proceed in the gas phase at room temperature increases, and the formation of a powder-like polymer is promoted. On the contrary, a polymer film is not formed on the substrate, resulting in a decrease in film formability.

There is also the problem that the powdered polymer contaminates the substrate or the interior of the reaction chamber.

The energy values of HOM O, UMO, and UMO are determined using the so-called P P method [P P P method], which is a semi-empirical method in LCA O-SCF calculations for handling π-electron systems. Bull method (Pariser - Parr -
The values calculated according to the Pople method)) were used. For such calculations, reference may be made to, for example, Sadatsugu Yonezawa et al., Introduction to Quantum Chemistry, 3rd edition, p. 275, published by Kagaku Doujin (1984). The parameters required for the calculations, ie, ionization potential, electron affinity, and -center electron repulsion integral, were taken from the literature. For literature, see Jay Hines (
J, Hinze), H, H, Jaffe (H,
H, J arfe), Jacks (J, Am, Ch
Em, Sac, ), Volume 84, Page 540 (1962
year), or MJ Nis Dev7-(lvl
, J.S., Dewar), T.Morita (T.Mo.
Rita), J. Am, Chem, Soc, vol. 91, p. 794 (1969). In addition, the two-center electron repulsion integral is the distance R between two atoms.
The theoretical formula proposed by Pearl was used within the range of 2.8 people.

The SCF property of the calculation was determined when the maximum value of the difference 1εi−ε/i+ between the MO energy εi and ε′i obtained in the previous calculation was less than 5×10−′.

The energy gap between the HOMO and LUMO mentioned above is 9
．． When using a hydrocarbon organic compound with a voltage of 5 to 11 eV,
Amorphous hydrogenated carbon films can be formed at low temperatures (room temperature to 100°C).

Therefore, the present invention can be coated not only on various heat-resistant ceramic products and metal products, but also on resins such as polymethyl methacrylate that have poor heat resistance, and on various devices that are susceptible to characteristic deterioration due to heat. It can be used for many purposes.

Therefore, the vine hydrocarbon organic compound applicable to the present invention is
This applies to those having a π-electron system, and the π-electron system includes carbon-carbon double bonds or triple bonds, and two or more of them may exist in a conjugated or non-conjugated state. .

The π-electron bond has the function of being cleaved during plasma polymerization to form a crosslinked structure between molecules. In the case of a compound that does not have a π-conjugated system, a film that is easy to peel off from the substrate, has no hardness, and is brittle is formed.

Specifically, cis-butadiene (10,47 eV), trans-butadiene (10,31 eV), propylene (9
, 83 eV), arene (10,52 eV), ■-butene (9,85 eV), and cyclobutene (10,54 eV).

The hydrocarbon organic compounds used in the present invention may be used alone or in combination.

Furthermore, other hydrocarbon compounds such as methane, ethane, ethylene, propane, etc. may be mixed and used within a range that does not impair plasma polymerization at low temperature and low frequency.

The amorphous carbon film of the present invention formed using such a compound has a hydrogen content of 10 to 60 atoms based on all constituent atoms.
c%, 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 uniformly deposited and formed.

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.

In the case of the hydrocarbon-based organic compound of the present invention, plasma polymerization is possible at low temperatures near room temperature, and it can be applied to various fields.

In plasma polymerization, molecules in the gas phase are decomposed by electrical discharge under reduced pressure, and activated neutral species or charged species contained in the generated plasma atmosphere are diffused onto a substrate and induced by electric or magnetic force. 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. The above-mentioned 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 Hayabusa 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 1000 KHz or higher, 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.

FIGS. 1 and 2 illustrate a capacitively coupled plasma CVD apparatus as an apparatus for manufacturing 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 include electrode plates (22), (25) and a substrate (24) in FIG.
The difference is that the electrode plate (30) and the substrate (31) in FIG. 2 have a cylindrical shape, whereas the electrode plate (30) and the substrate (31) in FIG. 2 are of a flat plate type. In addition, in the present invention, inductively coupled plasma C
It can also be produced using a VD device. The method for producing the amorphous hydrogenated carbon film of the present invention is carried out by parallel plate plasma CVD.
This will be explained by taking the apparatus (FIG. 1) as an example. (6) to (1) in the figure
0) are hydrocarbon organic compounds suitable for the present invention, H
The first to fifth tanks are hermetically sealed carrier gases such as L, He, and Ar, and other additive compound gases, and each tank is connected to the first to fifth regulating valves (11) to (15) and the mass flow controller (16). ) to (20). These gases are sent into the reaction chamber (23) via the main pipe (21).

The reaction chamber (23) is connected to a low frequency power source (
A flat earth electrode plate (25) is arranged opposite to the flat electrode plate (22) connected to the electrode plate (26), which is electrically grounded and on which the flat substrate (24) etc. are placed. There is. Further, the flat electrode plate (22) has a coil (27
) is connected to a DC voltage source (28), and in addition to the power applied from the low frequency power source (26), a DC bias voltage is additionally applied. Also, the electrode plate (2
5) If necessary, the substrate (24) etc. placed thereon are heated to, for example, room temperature to 100° C. by a heating means (not shown).

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 3 Qwatts to lkv 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). An amorphous hydrogenated carbon film (2) is formed.

Furthermore, other atoms, such as halogen atoms such as fluorine and chlorine, group II elements such as nitrogen, phosphorus, and arsenic, or group III elements such as boron, aluminum, gallium, and indium, may be added to the amorphous hydrogenated carbon film. is also possible, and for that purpose, vapors of compounds containing those elements are
The characteristics of the carbon film,
For example, wear resistance, 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 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 (H2, 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 according to the object to which the amorphous hydrogenated carbon film of the present invention is applied so that desired film characteristics can be obtained.

For example, if you want to form a carbon film with high hardness in terms of film properties, 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, SiH5itl~L gas, etc. may be used; as the germanium source, GeH, Get H* 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 B1Aσ, Ga1In, etc., and compounds containing B include B (OCyl-1s)s,
Examples include B t H*, BCl23, BBr3, and B Fa.

Compounds containing AQ include A 12 (Ot C3Ht
)a, (CH3)3Aσ, (C,H5)3A12, (t
C4Ha) s A QsAQC123 etc. are exemplified.

As a compound containing Ga, Ga(Oi C3H?)l
, (CHs)3Gas (C*Hs)sGa, GaCQ
3, GaBr5, etc.

As a compound containing In, I n (Of C3H?)
l, (CtHs)s I n, etc.

Examples of group V elements include P, As, Sb, etc., and compounds containing P include p o (o CH3)3, (C.

H5) 3 P, P H3, PF'5, POC (!a
etc.: As a compound containing AS, As H3, As C
12a, AsBr+, etc.: Compound containing Sb
(OCtH5)3.5bCQs, 5btr3, etc. are exemplified.

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. In addition, the content of atoms in the carbon film can be measured using infrared absorption spectroscopy, 'H-NMR, '3C-NMR, organic brother analysis,
This is possible using Auger spectroscopy, etc.

Using the various substrates shown in (a) to (p) below, film formation was attempted under the three conditions shown in Table 1 using the manufacturing equipment shown in Figure 1 (Examples 1 to 3) . For comparison, the results of film formation under conditions outside the scope of the present invention are also shown in Table 1 (
Comparative Examples 1-3).

(Substrate type) (a) Glass (Corning #7059) (b)
Silicon wafer (c) Aluminum plate (A6063) (d) Aluminum plate (A5386) (e) Stainless steel plate ([) Aluminum evaporated glass plate (g) Chrome sputtered glass plate (h) Gold evaporated glass plate (i) Tungsten wire ( D Copper plate (k) A Ss S es evaporated aluminum corrugated plate Q) GD
a-St deposited aluminum plate (m) Polyester resin (V-200 manufactured by Toyobo Co., Ltd.)
Coated aluminum plate (n) Polycarbonate resin (manufactured by Kijin Kasei-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. Valve ((11) to (12)
)), raw material gas from the first tank (6), H gas from the second tank (7), and the mass flow controller (1
6) to (17), the gas amount 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, film formability on various substrates was evaluated using ○ and X. ○ indicates that the film has excellent adhesion and obtained a score of 10 in the JIS-5400 standard substrate test, ×
indicates that it is difficult to form a film because it becomes oily, powdered, or peels off 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 given various properties by adding other atoms, etc., if desired.

[Brief explanation of the drawing]

FIGS. 1 and 2 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 type substrate, (25)...Flat type ground electrode plate,

Claims (1)

[Claims] 1. The energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is 9.5.
1. A method for producing an amorphous hydrogenated carbon film, comprising polymerizing a hydrocarbon-based organic compound having a voltage of 10 to 11 eV in vacuum using a low-frequency plasma discharge decomposition method with a frequency of 10 to 1000 KHz.