JPH02119010A - Insulation film - Google Patents

Abstract

PURPOSE:To improve heat resistance, electric insulation property, ion permeability resistance and preservation stability by forming an organic insulation film with a solution having a specified moisture content in which alicyclic polyamide, alicyclic polyamic acid or alkylamine salt of amic acid is dissolved. CONSTITUTION:Alicyclic polyamide, alicyclic polyamic acid or alkylamine salt of amic acid is dissolved, and the moisture content is specified at 0.001-15wt.%. A moisture content at less than 0.001wt.% is industrially insufficient because of a polar solvent, and a moisture content exceeding 15wt.% causes deposition of polyamide or a drop in the applicability to a substrate. It is possible, therefore, to improve heat resistance, electric insulation resistance, ion permeability resistance and preservation stability within a specified range of moisture content.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an insulating film, particularly an electrical insulating film made of an organic film that has excellent heat resistance, electrical insulation, ion permeation resistance, and storage stability, and has no pinholes. The present invention also relates to an insulating film suitable as an electronic device.

[Prior Art] Conventionally, an aromatic polyamic acid solution prepared by reacting an aromatic tetracarboxylic dianhydride and an aromatic diamine has been used as a heat-resistant insulating film used in electric or electronic devices, including wiring. Polyimide films that are formed by coating on a substrate and then heating at high temperatures have been used.

[Problems to be Solved by the Invention] However, the conventional aromatic polyamic acids are greatly affected by moisture in the solution, and as a result, the storage stability of the solution decreases due to the presence of moisture, and it is difficult to apply the solution. After that, pinholes occur in the polyimide film formed by imidization,
It was difficult to obtain a good insulating film.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems and provide an insulating film made of an organic film without pinholes, which has excellent storage stability, heat resistance, electrical insulation properties, and ion permeation resistance. It is in.

[Means for Solving the Problems] The present invention provides solutions for dissolving alicyclic polyimides, alicyclic polyamic acids, or alkylamine salts of the amic acids (hereinafter referred to as "alicyclic polyimides"). The present invention provides an insulating film made of an organic film formed using a solution having a water content of 0.001 to 15% by weight.

The alicyclic polyimide used in the present invention refers to an alicyclic polyamic acid obtained by reacting an alicyclic tetracarboxylic acid with a diamine in an organic solvent, or an alicyclic polyamic acid obtained by reacting an alicyclic tetracarboxylic acid with a diamine, and a long-chain alkylamine compound with the amic acid. It contains an alkylamine salt of the amic acid obtained by the reaction, and an alicyclic polyimide obtained by imidizing the amic acid and the alkylamine salt of the amic acid.

Note that the tetracarboxylic acids used in the present invention include tetracarboxylic acid, tetracarboxylic acid anhydride, tetracarboxylic dianhydride, tetracarboxylic acid monoalkyl ester, tetracarboxylic acid dialkyl ester, tetracarboxylic acid trialkyl ester, and tetracarboxylic acid tetraalkyl ester.

Such tetracarboxylic acids include 1,2°3.4.
-Cyclobutanetetracarboxylic acids, 1°2.3.4-
Cyclopentanetetracarboxylic acids, 2.3.5-tricarboxycyclopentyl acetic acids, 3,5.6-tricarboxy-norbornane 2-acetic acids, 5- (2,5-
dioxotetrahydrofuryl)-3-methyl-cyclohexenedicarboxylic acids, bicyclo(2,,2,2)-oct-7-nin-tetracarboxylic acids, 1. 2. 3
．． 4-furantetracarboxylic acids, 3.3', 4゜4
Examples include alicyclic tetracarboxylic acids such as -perfluoroisopropylidene tetracarboxylic acids. Among these tetracarboxylic acids, particularly preferred are 2,3.5 tricarboxycyclopentyl acetic acids and 1,2°3,4-cyclopentenetetracarboxylic acids.

In the present invention, the alicyclic tetracarboxylic acids include butanetetracarboxylic acids, 4゜4'-bis(3
, 4-dicarboxyphenoxy) diphenyl sulfides, 4.4'-bis(3゜4-dicarboxyphenoxy) diphenyl sulfones, 4.4'-bis(3,4-dicarboxyphenoxy) diphenylpropanes, 3 .3
', 4゜4'-perfluoroisopropylidene tetracarboxylic acids, 3.3', 4.4'-biphenyl ether tetracarboxylic acids, bis(phthalic acid) phenylphosphine oxides, p-phenylene-bis-(triphenyl phthalic acids), m-phinidine-bis-(triphenylphthalic acid), bis(triphenylphthalic acid)-4,4'-diphenyl ethers, bis(triphenylphthalic acid) 4,4'-diphenylmethane , pyromellitic acids, 3.3', 4.4'-benzophenonetetracarboxylic acids, 3.3', 4.4'-biphenylsulfonetetracarboxylic acids, 1.4. 5.8-
Naphthalenetetracarboxylic acids, 2,3,6.7-naphthalenetetracarboxylic acids, 3.3', 4゜4'-biphenylethertetracarboxylic acids, 3.3', 4.
Aliphatic or aromatic tetracarboxylic acids such as 4'-dimethyldiphenylsilane tetracarboxylic acids and 3.3', 4.4'-tetraphenylsilane tetracarboxylic acids can be used in combination. The proportion of these aliphatic or aromatic tetracarboxylic acids used in combination is usually 50 mol% or less, preferably 20 mol% or less, based on the alicyclic tetracarboxylic acids.

The diamines include para-phenylene diamine, meta-phenylene diamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ethane, benzidine, 4,4'-diaminodiphenyl sulfide, 4,4'-diamino Diphenylsulfone, 4.4'
-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3゜3'-dimethyl-4,4'-diaminobiphenyl, 3,4'-diaminobenzanilide, 3,
4'-diaminodiphenyl ether, 3.3'-diaminobenzophenone, 3.4'-diaminobenzophenone, 4.4'-diaminobenzophenone, 2°2-bis(4-(4-aminophenoxy)phenyl)propane,
Bis(1-(4-aminophenoxy)phenyl)sulfone, 1,4-bis(4-aminophenoxy)benzene,
1,3-bis(4-aminophenoxy)benzene, 1,
3-bis(3-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)-10-hydro-anthracene, 9,9-bis(4-aminophenyl)fluorene,
4.4'-methylene-bis(2-chloroaniline), 2
．． 2',5,5'-tetrachloro-4,4'-diaminobiphenyl, 2,2'dichloro-4,4-diamino-
Aromatic diamines such as 5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4゜4'-diaminobiphenyl, 1,1'-methaxylylene diamine, 1,3-
Propanediamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, 4,4'-dimethylhebutamethylene diamine, 1,4-diaminocyclohexane, isophorone diamine, tetrahydrodiamine Aliphatic or cycloaliphatic diamines such as cyclopentadienylene diamine, hexahydro-4,7-methanoindanilene shimethylene diamine, tricyclo(6,2,1,02.7)-landecylene dimethyldiamine, and RI R1 H2N-(CH2)-3i-(0-3N (C
H2) -NH2m
n mRI R1 (wherein, R1 is a methyl group having 1 to 12 carbon atoms, an ethyl group,
Alkyl group such as propyl group, alicyclic group such as cyclohexyl group, or aromatic group such as phenyl group, m is 1 to
An integer of 3, n represents an integer of 1 to 2o. ) and the like are diaminoorganosiloxanes.

The proportion of diamine used is usually 0.5 to 2 mol, preferably 0.8 mol, per 1 mol of tetracarboxylic acids.
~1.3 mol.

The reaction between the tetracarboxylic acids and the diamine is carried out in an organic solvent by a conventionally known method.

The organic solvent here is not particularly limited as long as it can dissolve the alicyclic polyamic acid obtained.
For example, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, bis(methoxyethyl)ether, tetrahydrofuran, chloroform, 1,4-dioxane. etc. can be mentioned.

In addition, the organic solvent in this case includes general organic solvents such as ethers, halogenated hydrocarbons, hydrocarbons such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, Diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, 0-dichlorobenzene, hexane, heptane, octane, benzene,
Toluene, xylene, etc. can also be mixed to the extent that alicyclic polyamic acid is not precipitated.

The amount of this organic solvent to be used is not particularly limited, but the amount is such that the solid content concentration is usually 0.1 to 30% by weight.

Moreover, the reaction between tetracarboxylic acids and diamines is usually carried out at 0 to 150°C, preferably at 0 to 80°C.

Furthermore, the alicyclic polyimide used in the present invention is synthesized by dehydrating and ring-closing the alicyclic polyamic acid obtained above in the same organic solvent as above using, for example, a dehydrating agent and a basic catalyst. be done. Here, as the dehydrating agent, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. Furthermore, the basic catalyst is not particularly limited, but tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used.

The amount of the dehydrating agent used is 0.8 to 1O equivalent to the amount of bonds to be dehydrated and ring-closed in the alicyclic polyamic acid, and the amount of the basic catalyst used is the amount of the dehydrating agent used in the organic solvent in which the alicyclic polyamic acid is dissolved. 0.5 to 10 equivalents, and the reaction temperature is usually 0 to 1
The temperature is 80°C.

The alicyclic polyimide solution obtained in this way is
Usually, the same organic solvent used in the reaction is used to prepare a solution having a solid content concentration of 0.05 to 20% by weight, preferably 1 to 15% by weight.

The alicyclic polyamic acid alkylamine salt used in the present invention is produced by reacting the alicyclic polyamic acid obtained above with a long-chain alkylamine compound.

This long-chain alkylamine compound has the following formula: (where,
R2 is a higher alkyl group, preferably an alkyl group having 6 to 30 carbon atoms, more preferably 10 to 25 carbon atoms, in view of good film forming properties, and R3 and R4 may be the same or different. , a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 6 carbon atoms. ) is an amine compound represented by Examples of the higher alkyl group for R2 include n-amyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n- -tridecyl group, n-tetradecyl group, n-pentadecyl group, n-
Hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-eicosyl group, n-henicosyl group, n-tocosyl group, n-tridecyl group, n-
Examples include a tetradecyl group and an n-triacontyl group. Examples of the hydrocarbon groups for R3 and R4 include alkyl groups such as methyl, propyl and pentyl groups, and alicyclic groups such as cyclohexyl.

”-2 Specific examples of long-chain alkylamine compounds include n
-amylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n
-pentadecylamine, n-hexadecylamine, n-
Primary amines such as heptadecylamine, n-octadecylamine, n-nonadecylamine, n-eicosylamine, n-henicosylamine, n-tocodylamine, n-tetradecylamine, n-1 liacontylamine, cyclohexylamine; N-methyl-n-octylamine, N-methyl-n-decylamine, N-methyl-n-dodecylamine, N-methyl-n-tetradecylamine,
Secondary amines such as N-methyl-n-hexadecylamine, N-n-octadecylamine, dicyclohexylamine, dioctylamine, didodecylamine, dioctadecylamine, dioctadecylamine; N,N-dimethyloctylamine, N , N-dimethyl-n-decylamine, N,N-dimethyl-n-dodecylamine, N,N-
Dimethyl-n-tetradecylamine, N,N-dimethyl-n-hexadecylamine, N,N-dimethyl-n-octadecylamine, N,N-dimethyl-〇-eicosylamine and N,N-dimethyl-n - Tertiary amines such as tocodylamine may be mentioned.

In order to obtain a good insulating film, it is preferable to use an alkylamine or aromatic amine compound having 1 to 30 carbon atoms, and more preferably an alkylamine or aromatic amine compound having 3 to 20 carbon atoms. .

The reaction between the alicyclic polyamic acid and the long-chain alkylamine compound can be carried out by adding the long-chain alkylamine compound as it is or adding the long-chain alkylamine compound to the reaction solution containing the resulting reaction product after producing the amic acid, or This can be carried out by mixing a solution of a long-chain alkylamine compound dissolved in an organic solvent that can be used for acid synthesis.

This reaction is usually carried out at 0 to 150°C, preferably at 0 to 60°C.
Can be done at ℃.

In this reaction, the amount of the long-chain alkylamine compound used is usually 0.00% per mole of repeating unit in the amic acid molecule. 5-5 mol, preferably 0. 5-3
It is a mole. The amount of the long-chain alkylamine compound used is too small relative to the repeating unit of the amic acid molecule,
If the amount is too large, a polyimide film with high film formability and insulation properties cannot be formed.

The reaction solution containing the alicyclic polyamic acid alkylamine salt obtained in this way is prepared using the same solvent as used in the reaction, and usually has a concentration of 0.1 to 10 mmol/1, preferably 0.1 to 10 mmol/1. It is used after preparing a solution of about 2 to 6a+mol/1.

In addition, the intrinsic viscosity η1nh of the polymer used in the present invention
(concentration 0.5g/100ml, solvent N, N-dimethylacetamide, measurement temperature 30°C) is preferably 0.0
5=ie/g or more, particularly preferably 0.05 to 20 ir/g
It is g.

The alicyclic polyimide solution obtained as described above has a water content of 0.001 to 15% by weight, preferably 0.001 to 15% by weight.
0.005 to 10% by weight. Moisture content 0.001% by weight
It is industrially difficult to reduce the moisture content to less than 15% by weight because the solvent used is a polar solvent, and if the moisture content exceeds 15% by weight, polyimide may precipitate depending on the solvent used or the applicability to the substrate may deteriorate. .

The organic film of the present invention is formed by applying and drying a solution of the alicyclic polyimide, and preferably using the alicyclic polyamic acid alkylamine salt obtained above, as described below. It is formed by the Langmuir-Prodgett method.

First, a solution of an alicyclic polyamic acid alkylamine salt is poured onto the water surface to form a monomolecular layer of the amic acid alkylamine salt on the water surface. Next, the surface pressure at which the monomolecular layer of the amic acid alkylamine salt is formed is usually set to 5 to 5.
40 dyn/cm, preferably 10-35 dyn/c
The substrate is immersed onto the water surface on which a monomolecular layer has been formed while maintaining the temperature at a constant speed, usually 0.
5-100mm/111ns preferably 1-30m
A monomolecular layer or a cumulative film of monomolecular layers of the amic acid alkylamine salt is formed on the surface of the substrate by repeating lifting and lowering at a speed of m/mlrr. The cumulative number of monomolecular layers formed can be made as desired by appropriately selecting the number of times the substrate is lifted. In order for a monomolecular layer or a cumulative film of monomolecular layers made of the amic acid alkylamine salt to suitably function as an insulating film of the present invention, the monomolecular layer usually has a thickness of 1.
It is preferable to obtain a film that has been applied approximately 400 times, preferably 2 to 300 times.

If the number of times the monomolecular layer is accumulated is too large, it will take a long time to form the insulating film, and the productivity of the device will decrease.

The monomolecular layer or cumulative film of monomolecular layers of the alicyclic polyamic acid alkylamine salt formed on the substrate as described above is usually heated at 40 to 250°C, preferably at 100 to 250°C.
The organic film of the present invention can be obtained by drying at 00°C.

In addition, the organic film of the present invention can be formed by forming an organic film in a mixed solution of a dehydrating agent and a catalyst or in a solution obtained by dissolving the dehydrating agent and the catalyst individually after forming a monomolecular layer or a cumulative film of monomolecular layers. By sequentially immersing and heating the substrates, the alicyclic polyamic acid alkylamine salt may be ring-closed to form a polyimide film. As the dehydrating agent and the catalyst, the same ones used when imidizing the alicyclic polyamic acid can be mentioned.

The heating temperature for ring-closing the alicyclic polyamic acid alkylamine salt is usually 0 to 200°C, preferably 0°C.
~150°C.

Further, the organic film of the present invention may be formed by general coating and drying using a solution of the alicyclic polyimide.

Electrical and electronic devices using an insulating film made of an organic film formed using a solution of alicyclic polyimide used in the present invention can be manufactured, for example, by the following method.

First, a solution of alicyclic polyimide is applied onto a substrate containing a metal or a semiconductor using a roll coater method, a spinner method, or a spinner method.
It is applied by a printing method or the like to form an organic film, and this organic film is dried at a temperature of 80 to 200°C, preferably 120 to 200°C, for 5 to 180 minutes, preferably 30 to 90 minutes.

The thickness of this organic film after drying is usually 0.01 to 1 μm.
1 preferably 0.01 to 0.5 μm.

In addition, when applying a solution of alicyclic polyimide,
If necessary, in order to further improve the adhesion between the substrate and the organic film, apply a silane coupling agent or
It is also possible to apply a titanium coupling agent or the like.

Substrates used in electrical and electronic devices having the insulating film of the present invention include alumina, quartz, float glass, soda glass, flexible polyester films such as polyethylene terephthalate, polyethylene terephthalate, polyether sulfone, polycarbonate, etc.
Transparent substrates made of other plastic films can be used, and substrates with metal thin films formed on these substrates, metallic substrates, and S1SGaAs.

Semiconductors such as ZnS, Zn5eSCdS, BaTiO
Examples include ferroelectric substrates such as 3 and L1NbO3. Furthermore, metal thin films may be wired on these substrates depending on the purpose.

Next, electric and electronic devices using the insulating film of the present invention include, for example, a metal electrode/insulating film/semiconductor structure in which the insulating film of the present invention is formed on a compound semiconductor and a metal electrode is formed thereon. , used in photoelectric conversion elements and light emitting elements such as LEDs.

Furthermore, similar to the metal electrode/insulating film/semiconductor structure, a structure in which an insulating film is formed on a semiconductor substrate and two or more elements are formed on it is a CCD (Charge-coupled
It is used in charge transfer type devices such as devices. Next, a structure in which a metal electrode, an insulating film, and a metal electrode are stacked in this order on an insulating substrate or a semiconductor substrate can be used as a transistor or a capacitor. Furthermore, it can also be used as an element with an insulating film/metal electrode structure used in liquid crystal alignment films and the like.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example N, N-dimethylacetamide/benzene (50150
, volume ratio) in the mixed solution was dissolved an alicyclic polyamic acid synthesized from 2,3.5-tricarboxycyclopentyl acetic dianhydride and 4゜4'-diaminodiphenyl ether to make a solution with a concentration of 1 mmol/2. Prepared. In this solution, a concentration of 1 mmol/N,N-dimethyl-n-octadecylamine was dissolved in the same mixture as above.
The Q solution was mixed so that the diamine was twice the molar amount per mole of the repeating unit of the amic acid, and water was further added to prepare an alicyclic polyamic acid alkylamine salt solution. The water content of this solution is 5% by weight. This solution was poured onto ion-exchanged water (25°C) filled in a water tank, and while maintaining the surface pressure in the water tank at 25 dyn/cm, the substrate was immersed at an angle of 4511 with respect to the water surface and moved up and down to form single molecules. A monolayer cumulative film consisting of 10 layers was formed on the surface of the substrate.

The substrate used was a circular glassy carbon electrode with a diameter of 5 mm. The substrate was pulled up at a rate of 5 mm/min, and after the cumulative film was formed, pyridine/acetic anhydride/benzene (
1:1:3 weight ratio) for 24 hours, and imidization was performed at a reaction temperature of 10 to 30°C. The IR spectrum of the organic film before imidization by treatment with pyridine/acetic anhydride/benzene has a wavenumber of 2800 to 3000.
cm-' showed a strong absorption attributed to C-H stretching vibration, but this absorption completely disappeared in the film after treatment, indicating that imidization occurred and an organic film of polyimide was formed. It was confirmed.

An element having a metal electrode/insulating film structure obtained using the insulating film made of an organic film thus formed was used as one electrode, and 1
mMK4 [Fe (CN)6] -0゜When the redox reaction of ions was investigated using cyclic portammetry in a 1M KCl aqueous solution, no current flowing between the electrodes was observed, as shown in Figure 1. It was shown that the polyimide membrane of the present invention has high ion permeability.

Next, an electrode with a diameter of 5 mm is formed on the insulating film of the aluminum metal electrode/insulating film structure by gold vapor deposition, and the metal electrode/insulating film is
When an element with an insulating film/metal electrode structure was formed and the electrical resistance value between metals was examined, the volume resistivity was 101.
A value of 8Ω·em or more was obtained, indicating that the insulating film of the present invention has excellent insulation properties.

Further, the thermal decomposition initiation temperature of polyimide produced in the same manner as measured with a differential thermal calorimeter was 430° C., indicating that the insulating film of the present invention has excellent heat resistance.

Comparative Example Instead of the polyamic acid used in the example, a polyamic acid synthesized from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether was used to prepare a solution of polyamic acid alkylamine salt in the same manner as in the example. . The water content of this solution is 0.1% by weight. Using the obtained solution of polyamic acid alkylamine salt, a polyimide film was formed in the same manner as in the example.

Next, an element with a metal electrode/insulating film structure was fabricated using the polyimide film in the same manner as in the example, and 1mMK4 [Fe
(CN) When the redox reaction of ions was investigated using cyclic portammetry in a 6-0.1 M KCl aqueous solution, a current value of 5 μA was observed, indicating that ions were permeating.

[Effects of the Invention] The insulating film of the present invention is made of an organic film with no pinholes and has excellent heat resistance, electrical insulation, ion permeation resistance, and storage stability. and useful in electronic devices.

[Brief explanation of the drawing]

Figure 1 shows the results of cyclic portammetry using the metal electrode/insulating film structure electrode shown in the example, where the horizontal axis shows the applied voltage and the vertical axis shows the current value flowing between the electrodes. . Patent applicant: Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] An insulating film made of an organic film formed using a solution containing an alicyclic polyimide, an alicyclic polyamic acid, or an alkylamine salt of the amic acid and having a water content of 0.001 to 15% by weight.