JP6821991B2 - Insulating film and organic field effect transistor device containing it - Google Patents

Description

The present invention has photocrosslinkability, excellent electrical insulation, low leakage current, and high dielectric breakdown strength, and after cross-linking, exhibits solvent resistance to organic semiconductor solutions using various organic solvents and is excellent. The present invention relates to an insulating film made of a polymer having both flatness and wettability.

Organic field effect The polymer for forming the polymer dielectric layer (insulating film layer) used in the transistor device exhibits high dielectric breakdown strength, low leakage current, solubility in general-purpose organic solvents, and solvent resistance. Therefore, the cross-linking property is required, and the polymer dielectric layer after cross-linking is required to have wettability against an organic solvent and high flatness.

Dielectric breakdown strength refers to the maximum electric field value that can be applied without destroying the dielectric layer that constitutes the device. The higher the dielectric breakdown strength, the higher the stability of the device. The leakage current density is an index showing the magnitude of the current flowing from the gate electrode to the source electrode through the dielectric layer having insulation properties, for example, a path other than the original conductive path. The leakage current is obtained by manufacturing an MIM capacitor having a three-layer structure of metal / dielectric / metal and measuring the current value flowing in the dielectric layer.

Solubility in general-purpose solvents is an essential requirement for manufacturing organic field-effect transistor devices by the printing method, while in organic field-effect transistor devices, the polymer dielectric layer is an overlay layer such as an organic semiconductor layer. Stacked. Therefore, when the overlay layer is formed on the polymer dielectric layer by a printing method using a solvent, it is necessary that the polymer dielectric is insoluble in the present solvent (solvent used in the printing method). .. Therefore, the polymer dielectric layer (insulating film layer) must be soluble in a general-purpose organic solvent when the layer is formed, and insoluble in the organic solvent after the layer is formed. Conflicting performance is required.

As a technique for meeting such a demand, a technique for cross-linking a polymer dielectric layer formed by a solution film is known. For example, benzocyclobutene resin (trademark cycloten) and polyvinylphenol resin (trademark Marlinker) are known, but benzocyclobutene resin has a high cross-linking temperature of 250 ° C. and is a base material when plastic is used as a base material. However, it is difficult to use because it undergoes thermal deformation, and it has a long curing time and is inferior in economic efficiency. Furthermore, it is extremely difficult to apply it to the roll-to-roll process, and the flatness of the film, which affects the device performance, is not sufficient. Polyvinylphenol uses a melamine resin or the like as a cross-linking agent and requires a long-term curing reaction at a temperature of about 150 ° C., and is extremely difficult to apply to the roll-to-roll process. Further, the hydroxyl groups of the polyvinylphenol resin are not completely eliminated, and the high leakage current presumed to be caused by the additives and the hydrophilicity due to the remaining hydroxyl groups has become a problem. Furthermore, the flatness of the film was not sufficient.

Among the types of polymers that do not require cross-linking, fluorocyclic ether resin (trademark Cytop) and polyparaxylylene resin (trademark parylene) are used as polymers for the polymer dielectric layer (insulating film layer). Etc. have been proposed. Since the fluorocyclic ether resin does not dissolve in a general-purpose organic solvent after film formation, it has an advantage that it is insoluble in a general-purpose solvent even when it is not crosslinked, but it is inferior in economic efficiency. Further, since the surface tension of this material is low, the wettability to the base material is poor, and the base material that can be coated or printed is also greatly restricted. In addition, there is also a problem that pinholes are easily formed due to poor wettability and the leakage current is high. Polyparaxylylene resin has the advantage that it does not dissolve in general-purpose solvents because the monomer is vapor-deposited on the substrate by the vacuum vapor deposition method and polymerized on the substrate to form a film, but it is suitable for printing processes and roll-to-roll processes. It has a fatal defect that it cannot be dealt with. As described above, the polymer used for the conventionally known polymer dielectric layer (insulating film layer) has solubility in a general-purpose solvent, cross-linking temperature, time required for cross-linking, solvent resistance, leakage current, and wetting with a solvent. There are some problems regarding properties, flatness when formed into a film, and the like, and a polymer capable of solving all of these problems and a polymer dielectric layer (insulating film layer) containing the polymer have been required.

Photocrosslinking technology is known as a means for crosslinking at a low temperature and shortening the crosslinking time. For example, a photocrosslinking property such as a cinnamoyl group can be obtained with respect to a polymer having a hydroxyl group in a side chain such as poly (hydroxyethyl methacrylate), vinylphenol-methyl methacrylate copolymer, polyacetoxyethyl methacrylate, polyhydroxyethyl methacrylate and the like. A technique for using a photocrosslinkable polymer obtained by reacting a compound having a compound as a polymer dielectric is disclosed (see, for example, Patent Document 1). However, in Patent Document 1, it is difficult to react all the hydroxyl groups existing in the above-mentioned hydroxyl group-containing polymer with the photocrosslinkable compound like the above-mentioned polyvinylphenol, and the residual hydroxyl groups are unavoidable. Further, Patent Document 1 also discloses a technique for reducing the amount of residual hydroxyl groups by reacting unreacted hydroxyl groups with trifluoroacetic anhydride to esterify them. However, it is extremely difficult to completely eliminate the hydroxyl group, and the introduction of the fluorine compound has an adverse effect that the wettability to the organic solvent is lowered.

Further, a technique of using poly (vinyl silicate) as a polymer dielectric of an organic field effect transistor device has been proposed (see, for example, Non-Patent Document 1 and Non-Patent Document 2), but the solution-coated high molecular weight. The flatness of the molecular dielectric layer (insulating film layer) was about 0.7 nm, and further flattening was required.

In addition to these, photocrosslinking technology and technology using a photocrosslinkable resin are known (see, for example, Non-Patent Document 3 and Non-Patent Document 4). For example, polystyrene and poly-α-methylstyrene are known as resist materials. In the 1950s, a technique relating to a photosensitive polybenzalacetophenone resin obtained by reacting an aromatic vinyl compound polymer such as cinnamoyl chloride with cinnamoyl chloride was disclosed (see, for example, Patent Documents 2 and 3). However, no disclosure has been made so far regarding a technique for applying the resist material disclosed in Patent Documents 2 and 3 to an insulating film using printed electronics technology.

Patent No. 5148624 U.S. Pat. No. 2,566,302 U.S. Pat. No. 270,665

Applied Physics Letters, Vol. 92, p. 143306 (2008) Applied Physics Letters, Vol. 95, p. 073302 (2009) Journal of Environmental Nanotechnology Magazine, Volume 3, Issue 3, Page 1 (2014) Polymer Bulletin, Vol. 11, p. 191 (1984)

The present invention has been made in view of the above problems, and an object of the present invention is solubility in a general-purpose solvent, crosslinking temperature, time required for crosslinking, solvent resistance, dielectric breakdown strength, leakage current, wettability to a solvent, and a film. It is an object of the present invention to provide a polymer dielectric layer (insulating film layer) having excellent performance in terms of flatness in the case of.

As a result of diligent studies to solve the above problems, the present inventors have made an insulating film using a specific polymer, so that the insulating film is soluble in a general-purpose solvent, cross-linking temperature, time required for cross-linking, solvent resistance, and insulation. We have found that a polymer dielectric layer (insulating film layer) having excellent performance can be obtained in terms of breaking strength, leakage current, wettability to a solvent, and flatness when formed into a film, and to complete the present invention. I arrived.

That is, the present invention is an insulating film made of a polymer having repeating units of the formulas (1) and (2).

{(In formula (1), Ar is an allyl group of C6 to C19, Y is a hydrogen, halogen, cyano group, carboxyalkyl group, alkyl ether group, aryl ether group, alkyl group of C1 to C18, fluoroalkyl group, Alternatively, it represents a cycloalkyl group. In addition, k represents an integer of 0 to 5, and M is an organic group represented by the formula (A) or the formula (B).)

(In formula (A) or formula (B), R ₁ represents hydrogen or an alkyl group of C1 to C6.)}

{(In formula (2), Ar represents an allyl group of C6 to C19, Y represents an organic group defined in formula (1), m is an integer of 1 to 5, and n represents (pk). , P represent the total number of substitutable sites on the aromatic group Ar, Z represents at least one organic group selected from formulas (C) to (E), and M is the same as in formula (1). is there.)

In formulas (C) to (E), R ₂ and R ₃ independently represent hydrogen or an alkyl group of C1 to C6, respectively, and R _{4 to} R ₁₇ independently represent a halogen, cyano group and carboxyalkyl group, respectively. , Alkyl ether group, aryl ether group, C1 to C18 alkyl group, fluoroalkyl group, or cycloalkyl group.)}
The present invention will be described in detail below.

The insulating film of the present invention is an insulating film made of a polymer having the repeating units of the above formulas (1) and (2).

In formula (1), Ar represents an allyl group of C6 to C19.

The allyl group of C6 to C19 in Ar in the formula (1) is not particularly limited, and examples thereof include a phenyl group, a naphthyl group, an anthranil group, and a biphenyl group.

In the formula (1), Y represents a hydrogen, a halogen, a cyano group, a carboxyalkyl group, an alkyl ether group, an aryl ether group, an alkyl group of C1 to C18, a fluoroalkyl group, or a cycloalkyl group.

The halogen in Y in the formula (1) is not particularly limited, and examples thereof include chlorine and fluorine.

The carboxyalkyl group in Y in the formula (1) is not particularly limited, and examples thereof include a carboxymethyl group, a carboxyethyl group, and a carboxypropyl group.

The alkyl ether group in Y in the formula (1) is not particularly limited, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, and a butoxy group.

The alkyl group of C1 to C18 in Y in the formula (1) is not particularly limited, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group.

The fluoroalkyl group in Y in the formula (1) is not particularly limited, and for example, 1,1,1-trifluoroethyl group, 1,1,1,2,2-pentafluoropropyl group, 1,1, Examples thereof include 1,2,2,3,3-heptafluorobutyl groups.

The cycloalkyl group in Y in the formula (1) is not particularly limited, and examples thereof include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. In the formula (1), k represents an integer of 0 to 5.

In the formula (1), M is an organic group represented by the above formula (A) or the above formula (B).

In formula (A) or formula (B), R ₁ represents hydrogen or an alkyl group of C1 to C6.

There is no particular limitation on the alkyl group C1~C6 in _{R 1} in the formula (1), for example, a methyl group, an ethyl group, n- propyl group, an isopropyl group, etc. n- butyl group.

In formula (2), Ar represents an allyl group of C6 to C19.

The allyl group of C6 to C19 in Ar in the formula (2) is not particularly limited, and examples thereof include a phenyl group, a naphthyl group, an anthranil group, and a biphenyl group.

In formula (2), Y represents an organic group similar to the organic group defined in formula (1).

In equation (2), m represents an integer of 1 to 5, and n represents (pk). Here, p represents the total number of substitutable sites on the aromatic group Ar.

In formula (2), Z represents at least one organic group selected from formulas (C) to (E), and M is the same as in formula (1).

In formulas (C) to (E), R ₂ and R ₃ independently represent hydrogen or an alkyl group of C1 to C6, respectively, and R _{4 to} R ₁₇ independently represent a halogen, cyano group and carboxyalkyl group, respectively. , Alkyl ether group, aryl ether group, C1 to C18 alkyl group, fluoroalkyl group, or cycloalkyl group.

There is no particular limitation on the alkyl group C1~C6 in _R 2, _{R 3} in the formula (C) ~ formula (E), for example, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group And so on.

The halogen in R _{4 to} R ₁₇ in the formulas (C) to (E) is not particularly limited, and examples thereof include chlorine and fluorine.

The carboxyalkyl group in R _{4 to} R ₁₇ in the formulas (C) to (E) is not particularly limited, and examples thereof include a carboxymethyl group, a carboxyethyl group, and a carboxypropyl group.

The alkyl ether group in R _{4 to} R ₁₇ in the formulas (C) to (E) is not particularly limited, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, and a butoxy group. ..

There is no particular limitation on the alkyl groups of C1~C18 in _R 4 _{to R 17} in the formula (C) ~ formula (E), for example, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group , N-hexyl group, n-decyl group, n-octadecyl group and the like.

The fluoroalkyl group in R _{4 to} R ₁₇ in the formulas (C) to (E) is not particularly limited, and is, for example, a 1,1,1-trifluoroethyl group, 1,1,1,2,2-. Examples thereof include a pentafluoropropyl group and a 1,1,1,1,2,2,3,3-heptafluorobutyl group.

The cycloalkyl group in R _{4 to} R ₁₇ in the formulas (C) to (E) is not particularly limited, and examples thereof include a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

Examples of the organic group represented by the specific formula (C) include the following.

Examples of the organic group represented by the specific formula (D) include the following.

Examples of the organic group represented by the specific formula (E) include the following.

The polymer having the specific repeating units of the formulas (1) and (2) used in the present invention contains an aromatic group and also contains a hydroxyl group, an amino group, a thiol group and the like that react with an acid chloride. If not, it can be used without any restrictions.

In the present invention, there is no limitation on the molecular weight of the polymer having the repeating units of the above formulas (1) and (2), for example, 500 to 10,000,000 (g / mol). Can be used. From the viewpoint of the solution viscosity of the obtained polymer, it is preferably 10,000 to 100,000 (g / mol).

The polymers having the repeating units of the above formulas (1) and (2) used in the present invention can be produced by a known method, and a photodimerizable compound contains an aromatic group by a Friedel-Crafts acylation reaction. It is obtained by introducing it into a polymer. Here, in the present invention, the flatness of the film is excellent due to the introduction of the photodimerizable compound, and the flatness is inferior only with the aromatic group-containing polymer.

In the present invention, the photodimerizable compound is an acid chloride compound of cinnamic acid represented by the following formula (3), an acid chloride compound of benzoylvinylbenzoic acid represented by the following formula (4), and the following formula (5). The acid chloride compound of phenylethenyl benzoic acid represented is shown. Among these, it is preferable to use the acid chloride of cinnamic acid, which is easy to produce. In addition, two or more of these compounds can be used in combination as needed.

(Equation (3) to (5) _in, R 2 _{to R 17} are the same as defined in formula (C) - (E).)
The amount of the above-mentioned acid chloride charged to the polymer having the repeating units of the formulas (1) and (2) is contained in the polymer in order to improve the solubility of the obtained polymer in an organic solvent and the storage stability. The amount is preferably 0.005 to 1 mol, more preferably 0.05 to 0.7 mol, based on 1 mol of the phenyl group. The amount of photoreactive groups introduced into the phenyl group in the reaction is 0.01 from the viewpoint of ease of photocrosslinking, solvent resistance of the layer after photocrosslinking, solubility in organic solvents, and storage stability. The amount is preferably ~ 0.6 mol, more preferably 0.2 to 0.5 mol.

Examples of the aromatic group-containing copolymer introduced by the Friedelcrafts acylation reaction include polystyrenes such as poly-α-methylstyrene, poly-p-methoxystyrene, and syndiopolystyrene; polyvinylnaphthalene, polyvinylbiphenyl, and polyvinyl. Polypolyallyl ketones such as anthracene, polyvinylcarbazole, polyvinylphenylketone; styrene-butadiene random copolymers; ethylene / styrene random copolymers; styrene / acrylonitrile copolymers; styrene / alkyl methacrylate copolymers; styrene / α-phenyl Alkyl acrylate copolymer; styrene / maleic anhydride copolymer; styrene / acrylic acid copolymer; styrene / 4-vinylpyridine copolymer; styrene / trans-1,3-pentadiene copolymer; styrene / 2, 4,6-trimethylstyrene copolymer; styrene / p-acetoxystyrene copolymer; styrene / vinyl-tris (trimethoxysiloxy) silane copolymer; styrene / vinylbenzoate copolymer; styrene / vinylbutyl ether copolymer Examples thereof include petroleum resins, but in order to lower the dielectric constant and reduce the leakage current, it is preferable to use a copolymer composed only of aromatic hydrocarbons and aliphatic hydrocarbons. In addition, these polymers can be used in combination of two or more.

The Friedel-Crafts acylation reaction can be carried out using a reaction catalyst.

As the reaction catalyst that can be used in the present invention, known ones can be used, and anhydrous iron (III) chloride, anhydrous aluminum chloride and the like are exemplified. The amount of the catalyst added is 0.9 to 1.5 with respect to the above-mentioned acid chloride because it is suitable for avoiding complicated decalcification operation after the reaction and preventing a decrease in the reaction rate. It is preferably double molar.

The Friedel-Crafts acylation reaction is an exothermic reaction and causes a side reaction in which photoreactive groups are crosslinked by heating in this reaction system. In the present invention, in order to suppress the side reaction, it is preferable to carry out by a solution reaction in which the reaction temperature can be easily controlled. In the present invention, the reaction solvent used in the solution reaction can be used without any limitation as long as it is stable to the Friedel-Crafts reaction and is inert to the reaction. Therefore, a chlorine-based hydrocarbon solvent is preferably used. Examples of the chlorine-based hydrocarbon solvent include methylene chloride, carbon tetrachloride, 1,1,2-trichloroethane, and chloroform.

In the Friedel-Crafts acylation reaction, the reaction temperature is not particularly limited, but 0 ° C. to 40 ° C. is preferable from the viewpoint of economic efficiency related to cooling and heating.

In the Friedel-Crafts acylation reaction, the reaction time is not particularly limited, and examples thereof include 5 hours to 100 hours. From the viewpoint of reaction rate and economy, it is preferably 10 to 50 hours.

Further, the polymer having the repeating units of the formulas (1) and (2) may contain a cyclobenzobutene structure based on the dimerization of photocrosslinking groups as long as the solubility is not impaired. ..

Examples of the cyclobenzobutene structure based on the dimerization of the photocrosslinking group include structures represented by the following formulas (6) to (8).

(In the formula _(6), R 2 ~R ₈ is similar to Equation (3))

(In equation (7), R ₂ , R ₃ , and R _{9 to} R ₁₄ are the same as in equation (4)).

(In equation (8), R ₂ , R ₃ , and R _{9 to} R ₁₇ are the same as in equation (5)).
The insulating film of the present invention is formed by using a solution in which a polymer having the repeating units of the above formulas (1) and (2) is dissolved in a solvent.

The solvent can be used without any limitation as long as it is a solvent that dissolves the polymer. For example, cyclohexane, benzene, toluene, xylene, ethylbenzene, isopropylbenzene, N-hexylbenzene, tetralin, decalin, isopropylbenzene, etc. Aromatic hydrocarbons such as chlorobenzene; chlorinated aliphatic hydrocarbon compounds such as methylene chloride and 1,1,2-trichloroethylene; aliphatic cyclic ether compounds such as tetrahydrofuran and dioxane; ketone compounds such as methyl ethyl ketone and cyclohexanone; ethyl acetate, Ester compounds such as dimethylphthalate, methyl salicylate and amylacetate; alcohols such as N-butanol, ethanol and ISO-butanol; 1-nitropropane, carbon disulfide and the like are exemplified, and these solvents are mixed as necessary. Can be used.

The insulating film according to the present invention includes, for example, spin coating, drop casting, dip coating, doctor blade coating, pad printing, squeegee coating, roll coating, rod bar coating, air knife coating, wire bar coating, flow coating, gravure printing, flexo. It can be formed by printing, screen printing, inkjet printing, letterpress reversal printing, or the like. Since the insulating film of the present invention is formed by using these methods, the insulating film of the present invention needs to have excellent solubility in a general-purpose solvent.

When the insulating film according to the present invention is used as a polymer dielectric layer, it is preferably thin in order to increase the electric field effect and reduce the driving voltage. In the present invention, in order to avoid an increase in leakage current and prevent an increase in drive voltage, 10 to 2000 nm is preferable, and more preferably 50 to 1000 nm.

Further, when the insulating film according to the present invention is used as the polymer dielectric layer, an aromatic group-containing polymer having no photocrosslinkability can be mixed and used in forming the polymer dielectric layer, and the polymer can be used as the polymer. For example, polystyrenes such as poly-α-methylstyrene, poly-p-methoxystyrene, syndiopolystyrene; polyvinylnaphthalene, polyvinylbiphenyl, polyvinylanthracenes, polyvinylcarbazoles, styrene-butadiene random copolymers; ethylene. -Sterene random copolymer; among copolymers composed of polystyrene segment and polybutadiene segment, diblock copolymer, triblock copolymer, multiblock copolymer, star polymer, or dendrimer; styrene-isoprene random copolymer. Combined; among copolymers consisting of polystyrene segment and polyisoprene segment, diblock copolymer, triblock copolymer, multiblock copolymer, star polymer, or dendrimer; polystyrene segment and poly (ethylene / butylene) segment Among the copolymers composed of diblock copolymers, triblock copolymers, multiblock copolymers, star polymers, or dendrimers; among copolymers composed of polystyrene segments and poly (ethylene / propylene) segments. Diblock copolymer, triblock copolymer, multiblock copolymer, star polymer, or dendrimer; styrene / acrylonitrile copolymer; styrene / alkylacrylate copolymer; styrene / alkyl methacrylate copolymer; styrene / α-Fluoroalkyl acrylate copolymer; styrene / α-phenylalkyl acrylate copolymer; styrene / trifluoromethyl acrylate copolymer; styrene / maleic anhydride copolymer; styrene / acrylic acid copolymer; styrene / acetic acid Vinyl copolymer; styrene / 4-vinylpyridine copolymer; styrene / trans-1,3-pentadien copolymer; styrene / 2,4,6-trimethylstyrene copolymer; styrene / p-acetoxystyrene copolymer Combined; Poly (styrene / α-methylstyrene) copolymer; styrene / vinyl-tris (trimethoxysiloxy) silane copolymer; styrene / vinylbenzoate copolymer; styrene / vinylbutyl ether copolymer, polyvinylphenyl ketone, etc. Examples thereof include polyvinyl allyl ketones.

When the insulating film according to the present invention is used as the polymer dielectric layer, it can be used in a state in which the film is formed or, if necessary, photocrosslinked. In the present invention, when the film is formed and then used as a polymer dielectric layer without photocrosslinking, it exhibits good solubility in a general-purpose solvent used for forming the film, and further. It is necessary to be able to form an organic semiconductor layer on the upper part of the film using a solvent different from the general-purpose solvent. At this time, when the film has solvent resistance to the organic semiconductor solution, it can be used as the polymer dielectric layer in the state where the film is formed. If the solvent resistance is not excellent, the film cannot be formed by the printing method, and it is necessary to form the film by a method such as a thin film deposition method, which is inferior in economy to the printing method.

When the insulating film according to the present invention is used as the polymer dielectric layer, radiation is used for photocrosslinking, and examples thereof include ultraviolet rays having a wavelength of 245 to 350 nm. The irradiation amount is appropriately changed depending on the composition of the polymer dielectric, and examples thereof include 150 to 3000 mJ / cm ² , in order to prevent a decrease in the degree of cross-linking and to improve economic efficiency by shortening the process. It is preferably 150 to 1000 mJ / cm ² . The irradiation of ultraviolet rays is usually carried out in the atmosphere, but can also be carried out in an inert gas or in a constant amount of an inert gas stream, if necessary. If necessary, a photosensitizer can be added to promote the photocrosslinking reaction. The photosensitizer used is not limited in any way, and examples thereof include benzophenone compounds, anthracene compounds, anthracene compounds, thioxanthone compounds, and nitrophenyl compounds, but benzophenone having high compatibility with the polymer used in the present invention. Compounds are preferred. In addition, two or more kinds of the sensitizer can be used in combination as needed.

Since the insulating film of the present invention is crosslinked by ultraviolet rays, heating at the time of crosslinking is not essential. Therefore, the temperature at which the crosslinking is performed is not particularly limited, and the crosslinking can be performed in the temperature range of 0 to 40 ° C. (room temperature).

In addition, the insulating film of the present invention can be efficiently crosslinked in a short time, and the time required for crosslinking can be 10 minutes or less. Since it is suitable for controlling the cross-linking time, it is preferable that the time required for cross-linking is 1 to 10 minutes.

When the insulating film according to the present invention is used as a polymer dielectric layer, it can be used as a polymer dielectric layer in an organic field effect transistor (FET). The organic field transistor can be obtained, for example, by laminating an organic semiconductor layer having a source electrode and a drain electrode attached on a substrate and a gate electrode via a gate insulating layer (polymer dielectric layer).

The insulating film of the present invention has a low leakage current because the formation of fine holes (pinholes) that cause electric leakage is suppressed. When the insulating film of the present invention is used as a polymer dielectric layer, the leakage current is preferably 0.01 nA or less from the viewpoint of practicality as an organic field effect transistor (FET) element.

The insulating film of the present invention has excellent wettability to a solvent, and when used as a polymer dielectric layer, it is a bottom gate top contact (BGBC) type and top gate bottom contact (TGTC) type organic field effect transistor. When an appropriate amount of the organic semiconductor solution covering the S (source) electrode and the D (drain) electrode on the layer is applied to the device, the electrode can be completely covered.

The insulating film of the present invention has excellent flatness, and when used as a polymer dielectric layer, the surface roughness (Ra) must be 0.3 nm or less from the viewpoint of better flatness. preferable.

When the insulating film of the present invention is used as a polymer dielectric layer, the threshold voltage of the FET element exceeds 0 and is 2.0 V or less, or from the viewpoint of practicality as an organic field effect transistor (FET) element. It is preferably −2.0 V or higher and less than 0 V.

When the insulating film of the present invention is used as a polymer dielectric layer, the mobility of the FET element is 0.20 cm / Vs or more from the viewpoint of practicality as an organic field effect transistor (FET) element. preferable.

The insulation film of the present invention, when used as a polymer dielectric layer is from the standpoint of utility as organic field effect transistor (FET) element, on current / off current ratio of the FET elements 10 ⁶ or more Is preferable.

When the insulating film of the present invention is used as a polymer dielectric layer, it is preferable that there is no hysteresis of the source-drain current of the FET element from the viewpoint of practicality as an organic field effect transistor (FET) element.

When the insulating film of the present invention is used as a polymer dielectric layer, the dielectric breakdown strength of the FET element is preferably 3 MV / m or more from the viewpoint of practicality as an organic field effect transistor (FET) element. ..

In the present invention, the organic field effect transistor (FET) is a bottom gate / bottom contact (BGBC) type, a bottom gate / top contact (BGTC) type, a top gate / bottom contact (TGBC) type, and a top gate / top contact (TGTC). Any type may be used. Here, among these organic field-effect transistors having various structures, for example, the structure of a bottom gate-bottom contact (BGBC) type element is shown in FIG.

The base material that can be used in the present invention is not particularly limited as long as sufficient flatness for producing the device can be ensured. For example, glass, quartz, aluminum oxide, high-doped silicon, silicon oxide, tantalum dioxide, tantalum pentoxide, and indium are used. Inorganic material substrates such as tin oxide; plastics; metals such as gold, copper, chromium, titanium, aluminum; ceramics; coated paper; surface-coated non-woven fabrics, etc., and composite materials made of these materials or multiple layers of these materials. It may be a non-woven material. It is also possible to coat the surfaces of these materials in order to adjust the surface tension.

Plastics used as a base material include polyethylene terephthalate, polyethylene naphthalate, triacetyl cellulose, polycarbonate, polymethyl acrylate, polymethyl methacrylate, polyvinyl chloride, polyethylene, ethylene / vinyl acetate copolymer, polymethylpentene-1, polypropylene. , Cyclic polyolefin, Fluorinated cyclic polyolefin, Polyester, Polyolefin, Polycarbonate, Polypolyphenol, Polyvinyl alcohol, Poly (diisopropyl fumarate), Poly (diethyl fumarate), Poly (diisopropyl maleate), Polyether sulfone, Polyphenylene sulfide, Polyphenylene Examples thereof include ether, polyester elastomer, polyurethane elastomer, polyolefin elastomer, polyamide elastomer, and styrene block copolymer. In addition, two or more of the above plastics can be laminated and used as a base material.

The conductive gate electrode, source electrode, or drain electrode that can be used in the present invention includes gold, silver, aluminum, copper, titanium, platinum, chromium, polysilicon, VDD, indium tin oxide (ITO), and the like. A conductive material such as tin oxide is exemplified. Further, a plurality of these conductive materials can be laminated and used.

When forming the electrodes (forming the circuit pattern), the polymer dielectric layer is UV-crosslinked, and then the surface of the polymer dielectric layer is irradiated with vacuum ultraviolet (VUV) light using a light-shielding mask to make it hydrophilic. It is possible to form a modified circuit pattern. The irradiation time of VUV light varies depending on the structure of the polymer dielectric used and the distance between the light source and the surface of the polymer dielectric layer, but from the viewpoint of sufficient hydrophilicity and improvement of economic efficiency by shortening the process, 1 Minutes to 10 minutes are preferable, and 1 minute to 5 minutes are more preferable.

Further, in the BGTC type element, an electrode is formed on the above-mentioned base material or the organic semiconductor layer. In this case, the method for forming the electrode is not particularly limited, and examples thereof include vapor deposition, high-frequency sputtering, electron beam sputtering, and the like, and solution spin using an ink obtained by dissolving nanoparticles of the conductive material in water or an organic solvent. Methods such as coating, drop casting, dip coating, doctor blade, die coating, pad printing, roll coating, gravure printing, flexo printing, screen printing, inkjet printing, and letterpress reversal printing can also be adopted. Further, if necessary, a treatment for adsorbing fluoroalkyl thiol, fluoroallyl thiol or the like on the electrode may be performed.

The organic semiconductor that can be used in the present invention is not limited, and either N-type or P-type organic semiconductor can be used, and it can also be used as a bipolar transistor that combines N-type and P-type.

Examples of organic semiconductors include TIPS-pentacene (F-1), C8-BTBT (F-2), TES-ADT (F-3), Dif-TES-ADT (F-4), and polyhexylthiophene (F-5). ) Etc. are exemplified.

In the present invention, both low molecular weight and high molecular weight organic semiconductors can be used, and these can be mixed and used.

In the present invention, examples of the method for forming the organic semiconductor layer include a method of vacuum-depositing an organic semiconductor, a method of dissolving an organic semiconductor in an organic solvent, coating and printing, and the like, and the thin film of the organic semiconductor layer is formed. There are no restrictions as long as it can be formed. The solution concentration when coating or printing with a solution of an organic semiconductor layer in an organic solvent varies depending on the structure of the organic semiconductor and the solvent used, but from the viewpoint of forming a more uniform semiconductor layer and reducing the thickness of the layer. Therefore, it is preferably 0.5% to 5% by weight. The organic solvent at this time is not limited as long as the organic semiconductor is dissolved at a constant concentration capable of forming a film, and is hexane, heptane, octane, decane, dodecane, tetradecane, decalin, indan, 1-methylnaphthalene, 2-ethyl. Naphthalene, 1,4-dimethylnaphthalene, dimethylnaphthalene isomer mixture, toluene, xylene, ethylbenzene, 1,2,4-trimethylbenzene, mesityrene, isopropylbenzene, pentylbenzene, hexylbenzene, tetraline, octylbenzene, cyclohexylbenzene, 1 , 2-Dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, trichlorobenzene, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, γ-butyrolactone, 1,3-butylene glycol, ethylene glycol , Benzene alcohol, glycerin, cyclohexanol acetate, 3-methoxybutyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, anisole, cyclohexanone, mesitylene, 3-methoxybutyl acetate, cyclohexanol acetate, Dipropylene glycol diacetate, dipropylene glycol methyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 1,6-hexanediol diacetate, 1,3-butylene glycol diacetate, 1,4-butanediol diacetate , Ethylacetate, phenylacetate, dipropylene glycol dimethyl ether, dipropylene glycol methyl-N-propyl ether, tetradecahydrophenylene, 1,2,3,4,5,6,7,8-octahydrophenylene, decahydro-2 -Naftor, 1,2,3,4-tetrahydro-1-naphthol, α-terpineol, isophorontriacetindecahydro-2-naphthol, dipropylene glycol dimethyl ether, 2,6-dimethylanisole, 1,2-dimethylanisole, 2 , 3-Dimethylanisole, 3,4-dimethylanisole, 1-benzothiophene, 3-methylbenzothiophene, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chloroform, dichloromethane, tetrahydrofuran , 1,2-Dimethoxyethane, dioxane, cyclohexanone, acetone, methyl ethyl ketone, diethyl ketone, diisopropyl ketone, acetophenone, N, N-dimethylformamide, N-methyl-2-pyrrolidone and the like, but the crystal film having preferable properties. A solvent having a high dissolving power of an organic semiconductor and a boiling point of 100 ° C. or higher is suitable for obtaining the above, and xylene, isopropylbenzene, anisole, cyclohexanone, mesityrene, 1,2-dichlorobenzene, 3,4-dimethylanisole, Pentylbenzene, tetraline, cyclohexanbenzene and decahydro-2-naphthol are preferred. Further, a mixed solvent in which two or more of the above-mentioned solvents are mixed at an appropriate ratio can also be used.

Various organic / inorganic polymers or oligomers, or organic / inorganic nanoparticles can be added to the organic semiconductor layer as needed, and a polymer solution can be applied onto the polymer dielectric layer to form a protective film. Further, various moisture-proof coatings, light-resistant coatings and the like can be applied on the protective film as needed.

According to the present invention, a polymer dielectric having excellent performance in terms of solubility in a general-purpose solvent, cross-linking temperature, time required for cross-linking, solvent resistance, leakage current density, wettability to a solvent, and flatness when formed into a film. Can provide a body layer.

It is a figure which shows the structure by the cross-sectional shape of the bottom gate-bottom contact (BGBC) type element.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. The organic semiconductor (di-n-hexyldithienobenzodithiophene) used in the examples was obtained by the production method of JP2015-224238A.

In the examples, spin coating, film thickness measurement, UV irradiation, and vacuum deposition were carried out with the following devices.
<Spin coating>
MS-A100 manufactured by Mikasa Co., Ltd. was used.
<Film thickness measurement>
The measurement was performed using a Bruker Dectak XT stylus profiler.
<UV irradiation>
A mercury lamp activation device for physics and chemistry H-400-A / B manufactured by Irie Co., Ltd. and a high-pressure mercury lamp H-400P (manufactured by Toshiba Lighting & Technology Corporation) were used.
<Vacuum vapor deposition>
A small vacuum vapor deposition apparatus VTR-350M / ERH manufactured by ULVAC, Inc. was used.

In the examples, the wettability of the polymer dielectric layer, the dielectric breakdown strength, and the evaluation of the FET (field effect transistor) element were evaluated under the following conditions.
<Wetability of polymer dielectric layer>
1 μl each of 5 kinds of solvents having different surface tensions, toluene, tetraline, xylene, mesitylene, and chlorobenzene was added dropwise onto the polymer dielectric (polymer having repeating units of formulas (1) and (2)), and S When an appropriate amount of organic semiconductor solution covering the electrodes and D electrode is applied, if the shape at the moment when the droplet is applied is maintained or if it spreads wet, it can cover the entire electrode, which is good in this case ( 1 point) On the other hand, when the droplet shrinks and / or moves, it becomes impossible to cover the electrode, so the case where the liquid shrinks and / or moves is evaluated as a defect (0 point). .. A score of 5 will be given if good results are obtained with all solvents.
<Dielectric breakdown strength>
Silver was vacuum-deposited on a washed and dried 30 × 30 mm ² glass (Eagle XG manufactured by Corning Inc.) to form a gate electrode having a thickness of 30 nm. After that, a dielectric (insulator) is formed on the base material on which the gate electrode is formed, and the gold electrode is vacuum-deposited on the dielectric layer to prepare a MIM capacitor, and the voltage is applied between the silver and gold electrodes. Then, the voltage at which the current starts to flow inside the dielectric breakdown due to dielectric breakdown was measured, and the value divided by the thickness of the dielectric breakdown was defined as the dielectric breakdown strength.
<Evaluation of FET element>
A bottom gate bottom contact (BGBC) type element, which is a form of an organic electric current effect transistor, is manufactured, and the gate voltage is changed under the condition of a source-drain voltage of -60 volt using a semiconductor parameter analyzer SCS4200 manufactured by Caseley. The mobility, low leakage current density, on-current / off-current ratio, source-drain current hysteresis, and threshold voltage were evaluated.

Synthesis Examples 1 to 7 are shown below, but the reaction, purification, and drying were all carried out under yellow light or under shading. In addition, in the synthesis example, the reason why it was carried out under yellow light or under shading is to prevent the cross-linking reaction of the photodimerizable compound and the photocrosslinking reaction of the polymer into which the photodimerizable compound was introduced.
[Synthesis Example 1] Synthesis of Polymer 1 (Polymer 1 having repeating units of formulas (1) and (2)) 2.8 g of polystyrene (reagent, Aldrich) having a weight average molecular weight of 280,000 was placed in a 200 ml Schlenk tube. It was charged and 38 g of super-dehydrated methylene chloride (reagent, Tokyo Kasei) was added and dissolved. 0.47 g of anhydrous aluminum chloride (reagent, Wako Pure Chemical Industries, Ltd.) was added to this solution, and the flask was ice-cooled and stirred for 30 minutes. A solution prepared by dissolving 4.45 g of cinnamoyl chloride (reagent, Tokyo Kasei), which is an acid chloride compound of cinnamic acid, in 10 g of ultra-dehydrated methylene chloride is gradually added to this solution, and the mixture is reacted under ice-cooling for 10 minutes. The reaction was carried out at room temperature for 35 hours. The reaction solution was gradually poured into a beaker containing 100 g of ice under stirring to quench the reaction. After all the ice had melted, methylene chloride was removed from the reaction solution by an evaporator, and the pink solid and water were separated. The solid was washed twice with 50 ml of water and three times with 50 ml of methanol. This solid was dissolved in 100 ml of toluene, filtered using a Teflon filter, poured into 700 ml of methanol under stirring to reprecipitate the polymer, and separated using a Teflon filter. After repeating the reprecipitation operation of the polymer three more times, the polymer was dried under reduced pressure at room temperature to obtain 2.7 g of the polymer 1.
[Synthesis Example 2] Synthesis of Polymer 2 (Polymer 2 having Repeating Units of Formulas (1) and (2)) 0.9 g of polystyrene (reagent, aldrich) having a weight average molecular weight of 2500 was charged into a 100 ml Schlenk tube. , 10 g of super-dehydrated methylene chloride (reagent, Tokyo Kasei) was added and dissolved. 0.17 g of anhydrous aluminum chloride (reagent, Wako Pure Chemical Industries, Ltd.) was added to this solution, and the flask was ice-cooled and stirred for 30 minutes. A solution prepared by dissolving 0.16 g of cinnamoyl chloride (reagent, Tokyo Kasei), which is an acid chloride compound of cinnamic acid, in 5 g of super-dehydrated methylene chloride is gradually added to this solution, and the mixture is reacted under ice-cooling for 10 minutes. The reaction was carried out at room temperature for 141 hours. The reaction was quenched by gradually pouring the reaction solution into a beaker containing 100 g of ice under stirring. After all the ice had melted, methylene chloride was removed by an evaporator and the light brown solid and water were separated by filtration. The obtained solid was washed twice with water and then three times with methanol. This solid is dissolved in 50 ml of toluene, filtered using a Teflon filter, and then 500 ml of methanol is poured under stirring to precipitate the polymer, and the polymer obtained by filtration is dried under reduced pressure at room temperature to a weight of 1 g. Combined 2 was obtained.
[Synthesis Example 3] Synthesis of Polymer 3 (Polymer 3 having Repeating Units of Formulas (1) and (2)) 1 g of polyvinylnaphthalene (reagent, aldrich) having a weight average molecular weight of 30,000 was charged into a 100 ml Schlenk tube. , 15 g of super-dehydrated methylene chloride (reagent, Tokyo Kasei) was added and dissolved. 0.2 g of anhydrous aluminum chloride (reagent, Wako Pure Chemical Industries, Ltd.) was added to this solution, and the flask was ice-cooled and stirred for 30 minutes. A solution prepared by dissolving 0.2 g of cinnamoyl chloride (reagent, Tokyo Kasei), which is an acid chloride compound of cinnamic acid, in 5 g of ultra-dehydrated methylene chloride is gradually added to this solution, and the mixture is reacted under ice-cooling for 10 minutes. The reaction was carried out at room temperature for 43 hours. The reaction was quenched by gradually pouring the reaction into a beaker containing 100 g of ice. After all the ice had melted, methylene chloride was removed from the reaction solution by an evaporator, and the light brown solid and water were separated. After the solid was filtered and separated, it was washed twice with 50 ml of water and four times with 50 ml of methanol. This solid was dissolved in 50 ml of toluene, filtered using a Teflon filter, and then poured into 500 ml of methanol under stirring to reprecipitate the polymer and separated by a Teflon filter. The same reprecipitation operation was repeated three more times, and then dried under reduced pressure at room temperature to obtain 0.9 g of polymer 3.
[Synthesis Example 4] Synthesis of polymer 4 (polymer 4 having repeating units of formulas (1) and (2)): Poly (styrene-methylmethacrylate) copolymer (styrene-alkyl methacrylate copolymer) Synthesis of 1 g of a poly (styrene-methylmethacrylate) copolymer (reagent, aldrich) having a weight average molecular weight of 120,000 was charged into a 100 ml Schlenk tube, and 25 g of superdehydrated methylene chloride (reagent, Tokyo Kasei) was added and dissolved. 0.16 g of anhydrous aluminum chloride (reagent, Wako Pure Chemical Industries, Ltd.) was added to this solution, and the flask was ice-cooled and stirred for 30 minutes. A solution prepared by dissolving 0.15 g of cinnamoyl chloride (reagent, Tokyo Kasei), which is an acid chloride compound of cinnamic acid, in 5 g of ultra-dehydrated methylene chloride is gradually added to this solution, and the mixture is reacted under ice-cooling for 10 minutes. The reaction was carried out at room temperature for 35 hours. The reaction was quenched by gradually pouring the reaction into a beaker containing 100 g of ice. After all the ice had melted, methylene chloride was removed from the reaction solution by an evaporator, and the pale yellow solid and water were separated. After the solid was filtered and separated, it was washed twice with 50 ml of water and four times with 50 ml of methanol. This solid was dissolved in 50 ml of toluene, filtered using a Teflon filter, and then poured into 600 ml of methanol under stirring to reprecipitate the polymer and separated by a Teflon filter. The same reprecipitation operation was repeated three more times, and then dried under reduced pressure at room temperature to obtain 0.85 g of polymer 4.
[Synthesis Example 5] Synthesis of Polymer 5 (Polymer 5 having repeating units of formulas (1) and (2)) Poly (α-methylstyrene) (polystyrenes) having a weight average molecular weight of 300,000 in a 100 ml Schlenk tube. ) (Reagent, Aldrich) was charged, and 25 g of super-dehydrated methylene chloride (Reagent, Tokyo Kasei) was added and dissolved. 0.2 g of anhydrous aluminum chloride (reagent, Wako Pure Chemical Industries, Ltd.) was added to this solution, and the flask was ice-cooled and stirred for 30 minutes. A solution prepared by dissolving 0.2 g of cinnamoyl chloride (reagent, Tokyo Kasei), which is an acid chloride compound of cinnamic acid, in 5 g of ultra-dehydrated methylene chloride is gradually added to this solution, and the mixture is reacted under ice-cooling for 10 minutes. The reaction was carried out at room temperature for 36 hours. The reaction was quenched by gradually pouring the reaction into a beaker containing 100 g of ice. After all the ice had melted, methylene chloride was removed from the reaction solution by an evaporator, and the pale yellow solid and water were separated. After the solid was filtered and separated, it was washed twice with 50 ml of water and four times with 50 ml of methanol. This solid was dissolved in 50 ml of toluene, filtered using a Teflon filter, and then poured into 600 ml of methanol under stirring to reprecipitate the polymer and separated by a Teflon filter. The same reprecipitation operation was repeated three more times, and then dried under reduced pressure at room temperature to obtain 0.91 g of polymer 5.
[Synthesis Example 6] Synthesis of polymer 6 (polymer 6 having repeating units of formulas (1) and (2)) Poly (styrene / α-methylstyrene) copolymer (reagent, aldrich) in a 100 ml Schlenk tube. ) 1 g was charged, and 20 g of super-dehydrated methylene chloride (reagent, Tokyo Kasei) was added and dissolved. 0.2 g of anhydrous aluminum chloride (reagent, Wako Pure Chemical Industries, Ltd.) was added to this solution, and the flask was ice-cooled and stirred above for 30 minutes. A solution prepared by dissolving 0.2 g of cinnamoyl chloride (reagent, Tokyo Kasei), which is an acid chloride compound of cinnamic acid, in 5 g of ultra-dehydrated methylene chloride is gradually added to this solution, and the mixture is reacted under ice-cooling for 10 minutes. The reaction was carried out at room temperature for 35 hours. The reaction was quenched by gradually pouring the reaction into a beaker containing 100 g of ice. After all the ice had melted, methylene chloride was removed from the reaction solution by the evaporator, and the pale yellow solid and water were separated. After the solid was filtered and separated, it was washed twice with 50 ml of water and four times with 50 ml of methanol. This solid was dissolved in 50 ml of toluene, filtered using a Teflon filter, and then poured into 600 ml of methanol under stirring to reprecipitate the polymer and separated by a Teflon filter. The same reprecipitation operation was repeated three more times, and then dried under reduced pressure at room temperature to obtain 0.93 g of polymer 6.
[Synthesis Example 7] Synthesis of polymer 7 (polymer 7 having repeating units of formulas (1) and (2)) (synthesis of vinylphenyl ketone)
16.8 g of 3-chloropropiophenone (reagent, Aldrich) and 200 ml of chloroform (reagent, Tokyo Kasei) were charged in a 500 ml three-necked flask under a nitrogen stream, and 24.7 g of triethylamine (reagent, Tokyo Kasei) was added to 30 After dropping over 1 minute, the reaction was carried out at room temperature for 18 hours. The reaction solution was placed in a separatory funnel and washed twice with 200 ml of a 0.1 N hydrochloric acid aqueous solution, twice with 200 ml of pure water, and twice with 200 ml of a saturated aqueous sodium hydrogen carbonate solution. The organic layer was separated, dried over sodium sulfate, a small amount of hydroquinone was added, and the mixture was concentrated on an evaporator. The obtained concentrated solution was distilled under reduced pressure to fractionate the components at 113 to 115 ° C. under a pressure of 4 mmHg to obtain 13 g of vinylphenyl ketone. All of the above synthesis operations were performed under yellow light.
_{^{1 H-NMR (CDCl 3,}} 21 ℃): δ = 7.94 (D, 2H), 7.56 (T, 1 H), 7.47 (T, 2H), 7.16 (DD, 1H) ^{, 6.44 (D, 1 H)} , 5.94 (D, 1 H).

(Synthesis of polyvinylphenyl ketone)
10 g of vinyl phenylketone was charged under nitrogen into a 50 ml flask equipped with a stirrer and heated to 60 ° C. The nitrogen substitution operation was repeated three times using a vacuum pump with the vinyl phenylketone melted. A solution prepared by dissolving 32 mg of lauroyl peroxide in 1 ml of toluene was collectively added to the reactor under a nitrogen stream, and the reaction was carried out at 60 ° C. for 4 hours. After cooling the contents to 50 ° C., 20 ml of toluene was added under stirring. The reactor was then cooled to room temperature and poured into a 500 ml beaker containing 250 ml of methanol to precipitate and filter the polymer. The operation of re-dissolving the obtained polymer in 20 ml of toluene and reprecipitating it with methanol was repeated three times, and the mixture was dried under reduced pressure at 30 ° C. to obtain 2.5 g of polyvinylphenyl ketone. The weight average molecular weight measured by GPC was 53,000. All the above operations were performed under yellow light.

(Synthesis of Polymer 7)
5 g of polyvinylphenylketone (polyvinylallyl ketone) was charged into a 300 ml Schlenk tube, and 100 g of super-dehydrated methylene chloride (reagent, Tokyo Kasei) was added and dissolved. 1.1 g of anhydrous aluminum chloride (reagent, Wako Pure Chemical Industries, Ltd.) was added to this solution, and the flask was ice-cooled and stirred for 30 minutes. A solution prepared by dissolving 1.0 g of cinnamoyl chloride (reagent, Tokyo Kasei), which is an acid chloride compound of cinnamic acid, in 20 g of super-dehydrated methylene chloride is gradually added to this solution, and the mixture is reacted under ice-cooling for 10 minutes. The reaction was carried out at room temperature for 50 hours. The reaction was quenched by gradually pouring the reaction into a beaker containing 500 g of ice. After all the ice had melted, methylene chloride was removed from the reaction solution by an evaporator, and the pale yellow solid and water were separated. After the solid was filtered and separated, it was washed twice with 500 ml of water and six times with 500 ml of methanol. This solid was dissolved in 300 ml of toluene, filtered using a Teflon filter, and then poured into 1500 ml of methanol under stirring to reprecipitate the polymer and separated by a Teflon filter. The same reprecipitation operation was repeated 6 times, and then dried under reduced pressure at room temperature to obtain 0.93 g of polymer 7.

[Example 1] Insulating film and organic field effect transistor Silver was vacuum-deposited on a 30 × 30 mm ² glass (base material) (Eagle XG manufactured by Corning Inc.) that had been washed and dried to form a gate electrode having a thickness of 30 nm. A toluene solution (3 wt%) of the polymer 1 obtained in Synthesis Example 1 was spin-coated on the substrate on which the gate electrode was formed under the conditions of 500 rpm × 5 seconds and 1000 rpm × 20 seconds, and spin-coated at 40 ° C. for 1 minute. After baking (formation of an insulating film), an ultraviolet ray of 788 mJ / cm ² was irradiated to form a crosslinked polymer dielectric layer having a film thickness of 535 nm. Gold was vacuum-deposited on a substrate on which a gate electrode and a polymer dielectric layer were formed to form a source electrode having a thickness of 30 nm, a channel length of 50 μm, and an electrode width of 500 μm, and a drain electrode. Immediately after that, it was immersed in an isopropanol solution of 30 mmol of pentafluorobenzenethiol, taken out after 5 minutes, washed with isopropanol, and blow-dried. Then, a 0.5 wt% toluene solution of an organic semiconductor (di-n-hexyldithienobenzodithiophene) was drop-cast. After the solvent was volatilized and dried, a bottom gate / bottom contact (BGBC) type organic field effect transistor device was produced. Table 1 shows the configuration, evaluation results, etc. of the produced organic field-effect transistor device.

The drain-source voltage _{V DS} as -60 volts, a result of evaluating the present device by varying the gate-source voltage, mobility 0.3 cm ² / V · S, the leakage current density 0.01nA / cm ^2, the current between the source and drain not observed hysteresis on current / off current ratio of 10 ⁵ or more, the dielectric breakdown strength is at 3 MV / cm or more, the leakage current density, hysteresis on current / off current ratio , It was excellent in all of the dielectric breakdown strength.

[Examples 2 to 7]
An organic field-effect transistor device was produced after forming an insulating film using the polymer (polymer 2 to polymer 7) produced in Synthesis Examples 2 to 7 by the same method as in Example 1. Table 1 shows the configuration, evaluation results, etc. of the produced organic field-effect transistor device.

It was confirmed that it has excellent performance as an organic field effect transistor device as in Example 1.

[Comparative Examples 1 to 3]
As the polymer dielectric layer, Parylene-C (manufactured by Japan Parylene LLC) (Comparative Example 1), Cycloten (manufactured by Dow Electric Materials) (Comparative Example 2), Cytop (manufactured by AGC Asahi Glass Co., Ltd.) ( An organic field effect transistor device was manufactured using Comparative Example 3). Here, an organic field-effect transistor device was produced after forming an insulating film using the same method as in Example 1 except for Parylene-C (Comparative Example 1). For parylene-C (Comparative Example 1), the organic field effect was produced by the same method as in Example 1 except that the film was formed by the vacuum deposition method using SCS Lab Coater 2 (manufactured by Nippon Parylene LLC (model PDS2010)). A transistor device was manufactured. Table 1 shows the configuration, evaluation results, etc. of the produced organic field-effect transistor device.

Since parylene-C (Comparative Example 1) does not dissolve in an organic solvent, it is necessary to polymerize the film by vapor deposition, which is inferior in film forming property. Further, although Cytop (Comparative Example 3) has solvent resistance to a general-purpose solvent, it shows solubility only in a solvent which is significantly inferior in economic efficiency. It should be noted that the fluorine-based solvent has a low surface tension, and when Cytop is used, it has a problem in stackability with the organic semiconductor layer.

As for the organic electric current effect transistor device layer (polymer dielectric layer performance), Parylene-C (Comparative Example 1) is inferior in terms of cross-linking temperature, cross-linking time, and surface roughness (flatness), and cycloten (Comparative Example 1). 2) is inferior in terms of cross-linking temperature, cross-linking time, threshold voltage, on-current / off-current ratio, and hysteresis, and Cytop (Comparative Example 3) is inferior in terms of solvent wettability, threshold voltage, and mobility. It was confirmed that there was.

[Comparative Example 4]
Silver was vacuum-deposited on a washed and dried 30 × 30 mm ² glass (base material) (Eagle-XG manufactured by Corning Inc.) to form a gate electrode having a thickness of 30 nm. 2-Acetoxy1-methoxypropane (PGMEA) having a weight average molecular weight of 25,000 polyvinylphenol (Marlinker M manufactured by Maruzen Petroleum Co., Ltd.) having a concentration of 20% by weight on a substrate on which a gate electrode is formed (PGMEA) 0.1 ml of Aldrich) solution, 84% by weight butanol solution (made by Aldrich) of poly (melamine-co-formumaldehyde) methylated product (reagent: Aldrich) as a cross-linking agent diluted with PGMEA to a concentration of 10% by weight. 0.2 ml was mixed, spin-coated at 300 rpm for 5 seconds and 700 rpm for 30 seconds, and then crosslinked at 90 ° C. for 10 minutes and 150 ° C. for 1 hour to obtain a crosslinked film having a thickness of 550 nm. Gold was vacuum-deposited on the substrate on which the gate electrode and the crosslinked film were formed to form a source electrode having a thickness of 30 nm, a channel length of 50 μm, and an electrode width of 500 μm, and a drain electrode. Immediately after that, it was immersed in an isopropanol solution of 30 mmol of pentafluorobenzenethiol, taken out after 5 minutes, washed with isopropanol, and blow-dried. Then, a 0.5 wt% toluene solution of an organic semiconductor (di-n-hexyldithienobenzodithiophene) was drop-cast. After the solvent was volatilized and dried, a bottom gate / bottom contact (BGBC) type organic field effect transistor device was produced. Table 1 shows the configuration, evaluation results, etc. of the produced organic field-effect transistor device.

As for the organic field effect transistor device layer (polymer dielectric layer performance), it was confirmed that polyvinylphenol was inferior in terms of cross-linking temperature, cross-linking time, threshold voltage, on-current / off-current ratio, and hysteresis.

It is possible to provide an insulating film suitable for a high quality organic field effect transistor device that can be manufactured by printed electronics technology.

Claims (2)

An organic field-effect transistor device comprising an insulating film made of a polymer having the repeating units of the formulas (1) and (2) as a polymer dielectric layer.
{(In formula (1), Ar is an aryl group of C6 to C19, Y is a hydrogen, halogen, cyano group, carboxyalkyl group, alkyl ether group, aryl ether group, alkyl group of C1 to C18, fluoroalkyl group, Alternatively, it represents a cycloalkyl group. In addition, k represents an integer of 0 to 5, and M is an organic group represented by the formula (A) or the formula (B).)
(In formula (A) or formula (B), R ₁ represents hydrogen or an alkyl group of C1 to C6.)}
{(Wherein (2), Ar is an aryl group of C6~C19, Y is an organic group as defined in formula (1), m is an integer of from 1 to 5, n represents represents a (p-m). Here , P represent the total number of substitutable moieties on the aromatic group Ar, Z represents at least one organic group selected from formulas (C)-(E), and M is similar to formula (1). is there.)
(In formulas (C) to (E), R ₂ and R ₃ independently represent hydrogen or an alkyl group of C1 to C6, respectively, and R _{4 to} R ₁₇ independently represent hydrogen, halogen, cyano group, and carboxy, respectively. Represents an alkyl group, an alkyl ether group, an aryl ether group, an alkyl group of C1 to C18, a fluoroalkyl group, or a cycloalkyl group.)} Claim 1 is characterized in that a polymer having repeating units of the formulas (1) and (2) is used, and the polymer contains an insulating film containing a crosslinked structure as a polymer dielectric layer. The organic field effect transistor device according to.