JP4575725B2 - Electronic device and manufacturing method thereof - Google Patents

Description

The present invention is related to an electronic device, and a manufacturing method thereof.

Liquid crystal display, PDP (plasma display panel), organic EL (Electroluminescence)
A flat panel display such as a display has a portion formed by patterning a thin film layer such as an electrode, an MIM (Metal-Insulator-Metal) element, an MIS (Metal-Insulator-Semiconductor) element, an active element such as a TFT, or a light-emitting element. is doing. FIG. 11 is a schematic view (cross-sectional view) of the MIM, MIS, and TFT elements. The MIM element in FIG. 11A is formed by sequentially laminating a first electrode material 102, an insulating material 103, and a second electrode material 104 on a substrate 101. In the MIS element in FIG. 11B, a first electrode material 102, an insulating material 103, a semiconductor material 105, and a second electrode material 104 are sequentially stacked on a substrate 101. The TFT element in FIG. 11C has a field effect transistor configuration (planar type), which includes a gate electrode 106, a gate insulating film 107, a source electrode 108, a drain electrode 109, and a semiconductor layer 110, and includes a source electrode 108 and a drain. The gap 111 between the electrodes 109 corresponds to the channel length.

In recent years, electronic devices using organic materials for a part or all of them have been attracting attention because of their merit in manufacturing such as cost reduction and ease of enlargement, and the possibility of functions not found in inorganic materials.
On the other hand, in the electronic element as shown in FIG. 11, the insulating function of the material is indispensable for the expression of the characteristics. Here, as a physical property required as an insulating material, a high resistance value and a withstand voltage are required. In general, the values require a volume resistance value of 1 × 10 ¹⁴ Ω · cm or more and a withstand voltage of 1 MV / cm or more. Is done.
Polyimide materials have been studied for the purpose of making these values compatible with organic materials. However, the conventional electronic device has the disadvantages that a desired resistance value and dielectric strength cannot be obtained, reliability is insufficient, and sufficient electronic device characteristics cannot be obtained.

  Patent Document 1 proposes a field effect transistor using an organic semiconductor material whose carrier mobility is changed by a physical external stimulus such as light or heat. In manufacturing this transistor, the gap 111 (channel length) between the source electrode 108 and the drain electrode 109 shown in FIG. This is because the switching frequency (fc) represented by the following formula (1) is inversely proportional to the square of the channel length, and the formation of a fine channel is indispensable for high-speed switching characteristics.

fc = μVd / 2πL ² (1)
(Where μ is carrier mobility, Vd is source / drain voltage, and L is channel length)
In addition, since it is possible to flow a large current through the element by improving the carrier mobility of the semiconductor material, research aimed at improving the mobility is being actively conducted.

By the way, as a method of finely patterning a thin film layer, a photolithography method is generally used. The process is as follows.
(1) A photoresist layer is applied on a substrate having a thin film layer (resist application).
(2) The solvent is removed by heating (pre-baking).
(3) Irradiate ultraviolet light through a mask (exposure).
(4) The resist in the exposed area is removed with an alkaline solution (development).
(5) The unexposed portion (pattern portion) resist is cured by heating (post-bake).
(6) Immersion in an etching solution or exposure to an etching gas to remove the thin film layer where there is no resist.
(7) The resist is removed with an alkaline solution or oxygen radical (resist stripping).
However, in the case of the above-described process, expensive equipment and the length of the process have caused the cost to increase.
In recent years, pattern formation by a printing method has been attempted in order to reduce manufacturing costs. In Patent Document 2, organosiloxane is applied to a surface on which an electrode such as an insulating material layer is to be formed, and only the portion where the electrode is wired is made hydrophilic by UV exposure. A method of applying a conductive ink such as a (polyethylene-dioxythiophene) solution by inkjet is disclosed. In this case, the electrode pattern can be finely formed by a simpler process than the photolithography method. However, since the organosiloxane itself does not have an insulating function, it is necessary to take steps of insulating material application → organosiloxane application → exposure.

JP-A-7-86600 Japanese Patent Application Laid-Open No. 2002-261048

  A polyimide material as an insulating material is generally obtained by imidizing polyamic acid through a dehydration reaction represented by the following formula (2). In the formula (2), X is an arbitrary linking group, and n is the number of repeating units corresponding to the desired molecular weight.

  However, according to the study by the present inventors, it has been found that when the imidization rate is low, unreacted polyamic acid remains in the thin film, and a desired resistance value and withstand voltage cannot be obtained. The reason is that the polyamic acid represented by the formula (2) remains in the thin film, and this reduces the resistance value of the thin film by absorbing moisture in the atmosphere.

  On the other hand, in the reaction of the formula (2), the amide bond is hydrolyzed by the water generated by the dehydration reaction and the water dissolved in the polyamic acid solution to produce a dicarboxylic acid, and further, an acid anhydride is produced by heating. The side reaction illustrated in the following formula (3) occurs.

As a result of this reaction, polyamic acid has a low molecular weight, and impurities of acid anhydride are mixed in the polyimide thin film, which has been a cause of impairing the thin film reliability such as the dielectric breakdown voltage of the polyimide thin film. This particularly appears as a defect such as dielectric breakdown in the film thickness direction in the elements shown in FIGS.
Furthermore, when a semiconductor material is laminated in the presence of a carboxylic acid anhydride represented by the formula (3), the carboxylic acid anhydride may become a dopant at the interface, which may change the characteristics of the semiconductor material. It was a cause of deterioration of device characteristics.
In addition, when an electronic device constituent material is applied on a polyimide material layer by pattern formation by a printing method, if a side reaction as shown in Formula (3) occurs, polyamic acid or acid anhydride is used as a solvent for the coating solution. And the like were eluted, resulting in problems such as deterioration of device characteristics and reliability.

Accordingly, an object of the present invention is to provide an electronic device that can obtain sufficient reliability and electronic device characteristics, and that can easily form a fine pattern at low cost, and a method for manufacturing the same.

In the invention of claim 1, the electronic element having a polyimide material as an insulating material is a field effect transistor, and the imidization ratio of the polyimide material is 80% or more, and the dicarboxylic anhydride remaining in the polyimide material is 3% or less, and the surface of the layer of the polyimide material has two parts, a high surface energy part with a large critical surface tension formed by applying energy and a low surface energy part with a small critical surface tension, The electronic device is characterized in that a conductive layer is formed at a site of the high surface energy portion .
The invention of claim 2 is the electronic device according to claim 1, wherein the difference between the critical surface tension of the critical surface tension and a high surface energy portion of the low surface energy part is 10 mN / m or more .
The invention according to claim 3 is the electronic device according to claim 1 or 2 , wherein the low surface energy portion has a critical surface tension of 40 mN / m or less.
According to a fourth aspect of the present invention, the polyimide material layer is made of a polyimide composition including at least a first material and a second material, and the first material has energy higher than that of the second material. provided by a material that critical surface tension is changed greatly, the electronic device according to claim 1, wherein said second material, characterized in that it is a material having a function other than the wettability changing.
According to a fifth aspect of the present invention, the polyimide material layer has a material distribution in the film thickness direction, and the concentration of the first material in the outermost layer is higher than the concentration of the second material. The electronic device according to claim 4 .
The invention according to claim 6 is the electronic device according to claim 4 or 5 , wherein the first material is polyimide including a hydrophobic group in a side chain.
According to a seventh aspect of the present invention, there is provided a method of manufacturing an electronic device including an insulating layer having a polyimide material as an insulating material, wherein the imidization ratio of the polyimide material is 80% or more and the dicarboxylic acid remaining in the polyimide material Anhydride is 3% or less, and the insulating layer has a critical surface tension that changes due to energy application, a high surface energy part having a larger critical surface tension, and a low surface energy part having a smaller critical surface tension. And a conductive layer is formed on the high surface energy part. The conductive layer is formed by applying a polyimide material precursor and heating in a low humidity environment with a humidity of 1% or less. This is a method for manufacturing an electronic device.
The invention according to claim 8 is the method of manufacturing an electronic device according to claim 7 , wherein the energy application for changing the critical surface tension is ultraviolet irradiation.
The invention according to claim 9 is the method for manufacturing an electronic element according to claim 7 , wherein the method for forming the conductive layer is an ink jet method.
According to the present invention, (1) in an electronic device having a polyimide material as an insulating material, the imidization ratio of the polyimide material is 80% or more, and 3 dicarboxylic anhydrides remain in the polyimide material. %, And an electronic element formed by laminating a polyimide material layer and a semiconductor material layer, and (2) an electronic element having a polyimide material as an insulating material, the imidization ratio of the polyimide material is 80% or more. And an electronic device having a dicarboxylic anhydride remaining in the polyimide material of 3% or less and formed by coating a material capable of being coated on the polyimide material layer, (3) A display device using the electronic device according to any one of claims 1 to 6, and (4) an arithmetic device using the electronic device according to any one of claims 1 to 6. Kill.

According to the present invention, sufficient reliability and the electronic element characteristics can be obtained, the electronic device forming a low-cost and easy fine pattern becomes possible, its manufacturing method is provide.

  The electronic device of the present invention is characterized in that a polyimide material is used as an insulating material, the imidization ratio of the polyimide material is 80% or more, and the dicarboxylic anhydride remaining in the polyimide material is 3% or less. Yes. As a result, an electronic device that has high resistance and good insulation resistance and that provides high reliability can be obtained.

In the present invention, the imidization ratio, Ar, in the thermal scanning IR analysis in gas such as N _2, may be obtained by the peak intensity changes based on the imide ring around 1360 cm ^-1 or 1720 cm ^-1. Specifically, first, IR analysis is performed on the polyimide material at room temperature, and the peak intensity based on the imide ring at this time is defined as x. Thereafter, the temperature of the polyimide material is increased until the peak intensity does not change. The peak intensity at that time is y. At this time, if the value of 100x / y is 80 or more, the imidization rate is regarded as 80% or more. The temperature rising rate at this time is preferably 5 ° C./min. Or less. More preferably, it is 1 degrees C / min. Or less. In the present invention, the imidization rate is desirably 90% or more.

The dicarboxylic acid anhydride has a peak in the vicinity of 1850 cm ⁻¹ , and if the peak intensity is 3% or less with respect to the peak intensity x, the dicarboxylic acid anhydride remaining in the polyimide material is regarded as 3% or less. One method for reducing the abundance ratio of the dicarboxylic acid anhydride is to heat the polyimide material at a high temperature. For example, the heating temperature is 200 to 350 ° C. This is because not only the imidization reaction of the formula (2) is promoted, but the dicarboxylic acid anhydride may disappear due to thermal decomposition.
An evaluation method using XPS is also possible. When evaluating the dicarboxylic acid anhydride by XPS, the peak intensity ratio with the imide ring is different from the intensity ratio of the IR spectrum, and therefore it is necessary to prepare a calibration curve in advance. Moreover, although it becomes evaluation near the surface of a thin film, detection sensitivity is generally higher than IR.
The polyimide material in the present invention can be used as an insulating substrate in addition to being used inside an electronic element. By using it as an insulating substrate, a highly reliable substrate can be obtained.

  According to a preferred embodiment of the present invention, the electronic element is configured by laminating a polyimide material layer and a semiconductor material layer. For this reason, good electronic element characteristics can be obtained. This is because high resistance is realized by improving the imidization ratio of the polyimide material, and further, when laminated with a semiconductor material, the dicarboxylic acid anhydride represented by the formula (3) does not become a dopant of the semiconductor material. Because.

According to a preferred embodiment of the present invention, the electronic element is configured by depositing a material that can be applied and formed on the polyimide material layer. For this reason, it becomes possible to use a manufacturing facility by an inexpensive printing method in manufacturing the electronic device, and it is possible to realize cost reduction of the electronic device. In addition, since a low molecular compound such as polyamic acid does not remain in the polyimide material layer, when a coating liquid of a material that can be applied and deposited adheres to the surface of the polyimide material layer, a low molecular compound such as polyamic acid is used. Since it does not come into contact with the molecular compound, good electronic device characteristics can be realized.
In the present invention, examples of materials that can be applied and formed include conductive materials, semiconductor materials, and insulating materials.
Examples of conductive materials include chromium (Cr), Ta (tantalum), titanium (Ti), copper (Cu), aluminum (Al), molybdenum (Mo), tungsten (W), nickel (Ni), and gold (Au). Metal such as palladium (Pd), platinum (Pt), silver (Ag), tin (Sn), or (1) polyacetylene-based conductive polymer, polyparaphenylene and its derivatives, polyphenylene vinylene and its derivatives, etc. Polyphenylene conductive polymer, (2) polypyrrole and derivatives thereof, polythiophene, polyethylenedioxythiophene (PEDOT) and derivatives thereof, heterocyclic conductive polymers such as polyfuran and derivatives thereof, and (3) polyaniline and derivatives thereof Dissolve in a solvent at least one conductive polymer selected from the group consisting of ionic conductive polymers such as derivatives. Or dissolved coating solution is used. In addition, these conductive polymers may be used by increasing the conductivity by doping an appropriate dopant. As the dopant used for doping, it is preferable to use a dopant having a low vapor pressure such as polysulfonic acid, polystyrene sulfonic acid (PSS), naphthalene sulfonic acid, and alkyl naphthalene sulfonic acid.

  Examples of the semiconductor material used in the present invention include inorganic semiconductor materials such as CdS, fluorene, polyfluorene derivatives, polyfluorenone, fluorenone derivatives, poly-N-vinylcarbazole derivatives, poly-γ-carbazolylethyl glutamate derivatives, polyvinyl Phenanthrene derivatives, polysilane derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, arylamine derivatives such as monoarylamines, triarylamine derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, styrylanthracene derivatives, pyrazoline derivatives, Pyrene derivatives such as divinylbenzene derivatives, hydrazone derivatives, indene derivatives, indenone derivatives, butadiene derivatives, pyrene-formaldehyde, polyvinylpyrene , Stilbene derivatives such as α-phenylstilbene derivatives and bisstilbene derivatives, at least one organic semiconductor material selected from the group consisting of thiophene derivatives such as enamine derivatives and polyalkylthiophenes, or pentacene, tetracene, bisazo, trisazo Dyes, polyazo dyes, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, cyanine dyes, styryl dyes, pyrylium dyes, quinacridone dyes, indigo dyes, perylene dyes, polycyclic At least one selected from the group consisting of quinone dyes, bisbenzimidazole dyes, indanthrone dyes, squarylium dyes, anthraquinone dyes, and phthalocyanine dyes such as copper phthalocyanine and titanyl phthalocyanine The machine semiconductor material dispersed or dissolved in a solvent coating solution is used.

  Insulating materials used in the present invention include polyimide resin, styrene resin, polyethylene resin, polypropylene, vinyl chloride resin, polyester alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, polyvinyl butyral resin. Photo-curing of polyether resins, polyester resins, acrylic resins, silicone resins, epoxy resins, phenolic resins, urea resins, melamine resins, PFA, PTFE, PVDF and other fluororesins, parylene resins, epoxy acrylates, urethane acrylates, etc. Resin, and general formula M (OR) n or MR (OR ') n-1 [wherein R and R' are organic groups such as an alkyl group and a phenyl group; Group IVA to VIIA, Group VIII or IB to VIB A metal belonging to, n is an integer. ] The coating liquid which melt | dissolved or disperse | distributed the metal alkoxide shown by a solvent is used.

  According to a preferred embodiment of the present invention, the electronic element is a field effect transistor. For this reason, it becomes possible to use a manufacturing facility by an inexpensive printing method in manufacturing the electronic device, and it is possible to realize cost reduction of the electronic device. If the polyimide material in the present invention is used as a gate insulating film, a field effect transistor having high resistance, high reliability, and good electrical characteristics can be obtained.

According to a preferred embodiment of the present invention, in the field effect transistor described above, the surface of the polyimide material layer has a critical surface tension changed by energy application, and a high surface energy portion having a larger critical surface tension, The low surface energy part has a smaller critical surface tension and a conductive layer is formed at the high surface energy part.
For this reason, the conductive layer easily adheres to the high surface energy site, and it is possible to easily form fine electrode patterns while using low-cost printing equipment, so that high operating frequency transistors can be manufactured at low cost. It becomes possible. In addition, it is particularly preferable to form a semiconductor material layer, particularly an organic semiconductor material layer, at a low surface energy portion, because a good interface can be formed.

According to a preferred embodiment of the present invention, the difference between the critical surface tension of the low surface energy part and the critical surface tension of the high surface energy part is 10 mN / m or more.
In order to ensure that the liquid containing the conductive material adheres only to the high surface energy part that is lyophilic according to the pattern shape of the high surface energy part and the low surface energy part, and to form a conductive layer, the surface energy difference However, when the difference is set to 10 mN / m or more, the liquid containing the electronic element constituent material can be reliably attached onto the polyimide material layer.

The critical surface tension in the present invention is defined as follows.
FIG. 1 is a schematic diagram when the droplet 12 is in an equilibrium state at the contact angle θ on the surface of the solid 11, and Young's formula (4) is established.
γ _S = γ _SL + γ _L · cos θ (4)
Here, γ _S is the surface tension of the solid, γ _SL is the interface tension between the solid and the liquid, and γ _L is the surface tension of the liquid. The surface tension is substantially synonymous with the surface energy and has exactly the same value. When cos θ = 1, θ = 0 ° and the liquid gets completely wet. The value of γ _L at this time is γ _S −γ _SL , which is called the critical surface tension γ _{C of the} solid. γ _C can be easily obtained by plotting the relationship between the liquid surface tension and the contact angle using several types of liquids with known surface tensions, and obtaining the surface tension at which θ = 0 (cos θ = 1). Can be determined (Zisman plot). Liquids are easy to wet on solid surfaces with large γ _C (lyophilic), and liquids are difficult to wet on solid surfaces with small γ _C (lyophobic).

  Table 1 shows the difference (Δγc) between the critical surface tension of the low surface energy part and the critical surface tension of the high surface energy part of each material deposited on the glass substrate, and the polyaniline (aqueous conductive polymer). This is an evaluation of selective adhesion. For selective adhesion, an aqueous polyaniline solution was dropped onto an area including a pattern boundary composed of an energy imparted portion and an unapplied portion, and after removing the excess solution, the presence or absence of polyaniline on the unapplied portion (pattern defect) was observed. . In Table 1, material A is polyvinylphenol, B is polyimide, C is a fluorine-containing acrylate polymer, and D is polyimide having a hydrophobic group in the side chain.

  Therefore, it is understood that Δγc is desirably 10 mN / m or more, and more desirably 15 mN / m or more.

In the present invention, the critical surface tension of the low surface energy part is preferably 40 mN / m or less. For this reason, a semiconductor material with high mobility can be obtained, and pattern defects of the conductive material can be suppressed. Mobility in FET characteristics depends on the critical surface tension of the surface of the insulating material on which the semiconductor material is deposited, and tends to decrease rapidly when this value exceeds 40 mN / m. FIG. 2 is a graph showing the relationship between the critical surface tension (mN / m) and the movement amount (cm ² / Vs). The relationship was examined using six types of materials having different critical surface tensions A to F. Therefore, by setting the critical surface tension of the low surface energy part to 40 mN / m or less, high mobility can be obtained and a large current can be passed through the device.

  According to a preferred embodiment of the present invention, the polyimide material layer is composed of a polyimide composition including at least a first material and a second material, and the first material is compared with the second material. It is a material whose critical surface tension is greatly changed by application of energy, and the second material is a material having a function other than a change in wettability. For this reason, it becomes possible to give functions other than a surface tension change to a polyimide material layer. For example, when using a material that has a large change in wettability as the first material but has a problem with the insulation function, a desired function can be exhibited by adopting a material with excellent electrical insulation as the second material. . In the above example, the composition ratio of the second material excellent in electrical insulation and the first material whose critical surface tension is greatly changed by applying energy is, for example, 50/50 to 99 / mass as the latter / former. 1. As the mass ratio of the first material increases, the electrical insulation becomes lower, making it unsuitable as an insulating layer for electronic devices. On the other hand, when the mass ratio of the second material is increased, the wettability change is reduced, so that the patterning of the conductive layer is not good. Therefore, the mixing ratio of the two is preferably 60/40 to 95/5, and more preferably 70/30 to 95/5. When the first material is a polyimide containing a hydrophobic group in the side chain described below, examples of the second material include a polyimide having no side chain as shown in Chemical formula 10 below.

  FIG. 3 is a cross-sectional view of a polyimide material layer made of a polyimide composition containing at least a first material and a second material. The presence form of the first material and the second material in the polyimide material layer is not particularly limited. For example, in the form of FIG. 3, a polyimide composition layer 200 is provided on the substrate 21, and the first material contained in the layer 200 is the first material. The one material 231 and the second material 221 have a sea-island structure.

According to a preferred embodiment of the present invention, the polyimide material layer in the electronic device has a material distribution in the film thickness direction, and the concentration of the first material in the outermost layer portion is higher than the concentration of the second material. Is also expensive. More desirably in the present invention, the first material concentration in the outermost layer is preferably close to 100%. For this reason, the wettability changing function can be surely expressed. 4A to 4E are cross-sectional views of a polyimide material layer made of a polyimide composition including a first material and a second material, having a material distribution in the film thickness direction.
The structure as shown in FIG. 4A can be produced by sequentially laminating the layer 23 made of the first material 231 on the substrate 21 after making the layer 22 made of the second material 221. . As a manufacturing method, a vacuum process such as vacuum vapor deposition can be used, or a coating process using a solvent can be used.
As a process for obtaining a structure in which the concentration of the first material 231 increases toward the surface layer portion and the concentration of the second material 221 decreases toward the surface layer portion as shown in FIG. A method in which a solution in which the first material 231 and the second material 221 are mixed is applied onto the substrate 21 and dried. This is because when the polarity of the first material 231 is smaller than that of the second material 221, or when the molecular weight of the first material 231 is small, the first material 231 is evaporated before the solvent evaporates during drying. 231 moves to the surface side and forms a layer. When such a coating process is used, the layer made of the first material and the layer made of the second material are often not clearly separated by the interface. Applicable if one material concentration is higher than the second material concentration. Further, the one in which the distribution of the first material 231 is localized as shown in FIGS. 4C to 4E is also applicable to the present invention. For example, when the first material is made of three or more kinds of materials, the first material may have a laminated structure of three or more layers, and the material has a predetermined concentration distribution in the film thickness direction without having the layer structure. May be mixed.

In the present invention, the first material is preferably polyimide containing a hydrophobic group in the side chain. According to this embodiment, since the difference between the water repellent part and the hydrophilic part is increased by the application of energy, the liquid containing the electronic element constituent material can be reliably attached onto the polyimide material layer.
The polyimide containing a hydrophobic group in the side chain is, for example, a hydrophobic group directly or via a bonding group (not shown) on the main chain L having a skeleton such as polyimide or (meth) acrylate, as shown in the following conceptual structural formula. And a side chain R having a bond.

Examples of the hydrophobic group include groups having a terminal structure of —CF ₂ CH ₃ , —CF ₂ CF ₃ , —CF (CF ₃ ) ₂ , —C (CF ₃ ) ₃ , —CF ₂ H, —CFH _2, etc. Can be mentioned. In order to facilitate the orientation of molecular chains, a group having a long carbon chain length is preferable, and a group having 4 or more carbon atoms is more preferable. Furthermore, a polyfluoroalkyl group in which two or more of the hydrogen atoms of the alkyl group are substituted with fluorine atoms (hereinafter referred to as “Rf group”) is preferable, and an Rf group having 4 to 20 carbon atoms is particularly preferable. The Rf group having 6 to 12 carbon atoms is preferred. The Rf group may have a linear structure or a branched structure, but a linear structure is preferred. Further, the hydrophobic group is preferably a perfluoroalkyl group in which substantially all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms. The perfluoroalkyl group is preferably a group represented by C _n F _{2n + 1} — (where n is an integer of 4 to 16), particularly preferably when n is an integer of 6 to 12. The perfluoroalkyl group may have a linear structure or a branched structure, and a linear structure is preferred.

  The above materials are well-known and described in detail in Japanese Patent No. 2796575 and have the property of becoming lyophilic when brought into contact with a liquid or solid in a heated state and becoming lyophobic when heated in air. That is, the critical surface tension can be changed by applying thermal energy (selecting the contact medium).

Furthermore, examples of the hydrophobic group include groups having a terminal structure such as —CH ₂ CH ₃ , —CH (CH ₃ ) ₂ , and —C (CH ₃ ) ₃ that do not contain a fluorine atom. Also in this case, in order to facilitate the orientation of molecular chains, a group having a long carbon chain length is preferable, and a group having 4 or more carbon atoms is more preferable. The hydrophobic group may have a linear structure or a branched structure, but a linear structure is preferred. The alkyl group may contain a halogen group, a cyano group, a phenyl group, a hydroxyl group, a carboxyl group, or a phenyl group substituted with a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms or an alkoxy group. Good. It is considered that the more R binding sites, the lower the surface energy (the smaller the critical surface tension) and the more lyophobic. It is presumed that, due to the application of energy, part of the bond is broken, or the orientation state changes, so that the critical surface tension increases and becomes lyophilic.

Further, the hydrophobic group of the polyimide having a hydrophobic group in the side chain used in the present invention can have any one of chemical formulas represented by the following formulas (5) to (9).

In the formula (5), X is —CH ₂ — or —CH ₂ CH ₂ —, and A ¹ is 1,4-cyclohexylene, 1,4-phenylene, or 1,1 substituted with 1 to 4 fluorines. 1,4-phenylene which is 4-phenylene and each of A ² , A ³ and A ⁴ is independently a single bond, 1,4-cyclohexylene, 1,4-phenylene or 1 to 4 fluorines B ¹ , B ² and B ³ are each independently a single bond or —CH ₂ CH ₂ —, B ⁴ is alkylene having 1 to 10 carbon atoms, and R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ are each independently alkyl having 1 to 10 carbon atoms, and p is an integer of 1 or more.

  In the formula (6), T, U and V are each independently a benzene ring or a cyclohexane ring, and any H on these rings is alkyl having 1 to 3 carbon atoms or fluorine-substituted alkyl having 1 to 3 carbon atoms. , F, Cl or CN, m and n are each independently an integer from 0 to 2, h is an integer from 0 to 5, and R is H, F, Cl, CN or Two U in the case of a monovalent organic group and m being 2 or two V in the case where n is 2 may be the same or different.

In the formula (7), the linking group Z is CH ₂ , CFH, CF ₂ , CH ₂ CH ₂ or CF ₂ O, and the ring Y is 1,4-cyclohexylene or 1 to 4 Hs are F or CH. ¹ , 4-phenylene which may be replaced by ₃ , A ^{1 to} A ³ are each independently a single bond, 1,4-cyclohexylene or 1 to 4 H are replaced by F or CH ₃ 1,4-phenylene, and B ^{1 to} B ³ are each independently a single bond, alkylene having 1 to 4 carbon atoms, oxygen atom, oxyalkylene having 1 to 3 carbon atoms, or 1 to 3 carbon atoms. Alkyleneoxy, R is H, alkyl having 1 to 10 carbon atoms in which arbitrary CH ₂ may be replaced with CF ₂ , or carbon atoms having 1 to 9 carbon atoms in which one CH ₂ may be replaced with CF ₂ Of alkoxy or alkoxy Is alkyl, the bonding position of the amino group to the benzene ring is arbitrary position. However, when Z is CH ₂ , all of B ^{1 to} B ³ are not simultaneously alkylene having 1 to 4 carbon atoms, Z is CH ₂ CH ₂ , and ring Y is 1, 4 When it is -phenylene, both A ¹ and A ² are not a single bond, and when Z is CF ₂ O, ring Y is not 1,4-cyclohexylene. .

In the formula (8), R 2 is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, Z ₁ is a CH ₂ group, m is 0 to 2, ring A is a benzene ring or a cyclohexane ring, l is 0 or 1, each Y ₁ is independently an oxygen atom or a CH ₂ group, and each n ₁ is independently 0 or 1.

In formula (9), each Y ₂ is independently an oxygen atom or a CH ₂ group, R 3 and R 4 are independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or a perfluoroalkyl group, at least one of which is carbon It is an alkyl group of several or more, or a perfluoroalkyl group, and each n ₂ is independently 0 or 1.

Details of these materials are described in detail in JP-A No. 2002-162630, JP-A No. 2003-96034, JP-A No. 2003-267982, and the like. As for the tetracarboxylic dianhydride constituting the main chain skeleton of these hydrophobic groups, various materials such as aliphatic, alicyclic and aromatic materials can be used. Specifically, pyromellitic dianhydride, cyclobutane tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, and the like. In addition, materials described in detail in JP-A-11-193345, JP-A-11-193346, JP-A-11-193347, and the like can also be used.
As described above, the polyimides containing the hydrophobic groups (5) to (9) may be used alone or in combination with other materials. However, when mixed and used, considering the heat resistance, solvent resistance, and affinity, the material to be mixed is also preferably polyimide.

  Next, the manufacturing method of this invention is demonstrated. The manufacturing method of the present invention uses the polyimide material having an imidization rate of 80% or more and a dicarboxylic acid anhydride of 3% or less, and when forming an insulating layer of an electronic element, The precursor is formed by, for example, applying the precursor onto an electrode and heating, and the heating step is performed in a low humidity environment with a humidity of 1% or less. As described above, the insulating layer has a critical surface tension that changes due to energy application, and includes a high surface energy part having a higher critical surface tension and a low surface energy part having a lower critical surface tension. It is preferable that the conductive layer is formed at the site of the high surface energy part.

The precursor of the polyimide material is not particularly limited, and various materials may be selected so that a desired polyimide can be obtained. In the heating process, a low humidity environment with a humidity of 1 RH% or less is employed. For this reason, there are no by-products due to hydrolysis of the polyamic acid as seen in the formula (3), good electrical characteristics can be obtained, and a highly reliable electronic device can be manufactured.
In the present invention, a low-humidity environment of 1% or less is preferable also in the polyimide precursor coating step. This is because in the coating step, the polyimide precursor or the polyimide precursor solvent absorbs water and is then heated to cause a hydrolysis reaction of the polyamic acid of formula (3).
In addition, when the coating process is not in a low humidity environment, the polyimide material thin film is cooled by evaporation of the solvent after coating, which causes moisture in the atmosphere to condense and adhere to the thin film, so the heating process is not sufficiently low in the humidity environment. In some cases, heating is performed with moisture adhering to the surface of the thin film, which may also cause a hydrolysis reaction. In the present invention, it is more preferable that the humidity is 0.1% or less in both the coating process and the heating process.
Moreover, in this invention, it is preferable that it is a low oxygen concentration in a heating process. Generally, 21% oxygen is contained in the atmosphere. However, since there is a possibility of oxidative deterioration of the polyimide composition in the heating step, the concentration is preferably 2 to 3% or less.
In order to realize the above low humidity and low oxygen concentration environment, the heating process is preferably performed in an inert gas atmosphere such as Ar or He. N ₂ gas is also applicable.

  Further, according to the present invention, it is preferable that the application of energy for changing the critical surface tension is ultraviolet irradiation. Therefore, a fine pattern can be easily formed. FIG. 5 is a diagram for explaining a process of changing the critical surface tension using ultraviolet irradiation. As shown in FIG. 5A, an electrode 52 and a polyamide material layer 53 are sequentially provided on a substrate 51. The surface of the polyamide material layer 53 is irradiated with ultraviolet rays 55 through an exposure mask 54. As a result, as shown in FIG. 5B, a pattern composed of the high surface energy portion 56 and the low surface energy portion 57 is formed on the surface of the polyamide material layer 53. The ultraviolet rays preferably include light having a relatively short wavelength of 100 nm to 300 nm.

According to a preferred embodiment of the present invention, the method for forming the conductive layer is an ink jet method. Thereby, an electronic element constituent material can be formed only in the high surface energy part.
FIG. 6 is a diagram for explaining a process of forming a conductive layer by an inkjet method. As described above with reference to FIG. 5, the electrode 52 and the polyamide material layer 53 are sequentially provided on the substrate 51. The surface of the polyamide material layer 53 is irradiated with ultraviolet rays 55 through an exposure mask 54. Thereby, the pattern which consists of the high surface energy part 56 and the low surface energy part 57 is formed in the surface of the polyamide material layer 53 (Fig.6 (a)). According to one embodiment of the present invention, an inkjet method is used to form the conductive layer. Along with the miniaturization of the electrode wiring, the distance between the electrodes becomes small, and this may cause a short circuit when the conductive material is applied. By using the inkjet method, as shown in FIG. 6B, it becomes possible to provide the conductive layer 58 only in the high surface energy portion 56, so that it is possible to provide a highly reliable manufacturing process in microfabrication. Become.

  The present invention also provides a display device using the electronic element. For this reason, a manufacturing process reduces compared with the past, and an inexpensive display apparatus can be provided. Although it does not restrict | limit especially as a display apparatus, For example, a liquid crystal display device is mentioned. FIG. 7 is a wiring diagram of a liquid crystal display element using the electronic element of the present invention as an active element. A voltage is applied from the gradation signal line according to the gradation of each pixel. A signal voltage of ON / OFF is sequentially applied from the scanning line for each line, and after the scanning of one screen is completed, the scanning of the next screen is started. In the case of video support, it is desirable that this interval is 50 Hz or more (1/50 sec. Or less). The capacitor has a function of charging the voltage of the gradation signal for the time from the transition from one screen to the next screen.

The present invention also provides an arithmetic device using the electronic element. For this reason, a manufacturing process reduces compared with the past, and an inexpensive arithmetic unit can be provided. The arithmetic device is not particularly limited, and the electronic element of the present invention can be used for a conventionally known arithmetic device.
FIG. 8 is a diagram illustrating an example of an arithmetic circuit. p-ch and n-ch respectively indicate a transistor using a hole transport material and a transistor using an electron transport material. The arithmetic circuit of FIG. 8 is an example of a NOT arithmetic circuit, but other OR, NAND, NOR, XOR arithmetic circuits, etc. are integrated via an interlayer insulating film 201 as illustrated in FIG. 9A. In addition, a fine wiring electrode 202 is connected on the interlayer insulating film 201, whereby a highly integrated arithmetic element is configured. As is well known, the transistor 203 in this arithmetic element includes a gate electrode 204, a gate insulating film 205, a source electrode 206, a drain electrode 207, and a semiconductor 208 (FIG. 9B). In the configuration of FIG. 9, it is possible to use the polyimide material of the present invention as an interlayer insulating film.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not restrict | limited to the following example.
Examples 1-4, Comparative Examples 1-2
An active element made of a field effect transistor as shown in FIG. 11C was formed. The TFT element in FIG. 11C has a field effect transistor configuration (planar type), and includes a gate electrode 106, a gate insulating film 107, a source electrode 108, a drain electrode 109, and a semiconductor layer 110. As the source and drain electrodes, gold electrodes (formed by vapor deposition: width 4 mm) were used. The gate electrode was made of Al, and the channel length was 50 μm ± 5 μm.
As the semiconductor in the semiconductor layer, a compound represented by the following formula was used.

  Moreover, the following polyimide precursor was apply | coated on the gate electrode, and the gate insulating film was heated on the predetermined film-forming conditions, and the following polyimide was obtained. A TFT was prepared using polyimide thin films having different imidation ratios by thermal scanning IR analysis and different abundance ratios of dicarboxylic anhydrides by changing the polyimide film formation conditions. In the following formula, the aromatic ring of X is a benzene ring or a naphthalene ring.

  The electrical characteristics of the obtained TFT were evaluated using the evaluation apparatus shown in FIG. Here, the first power supply voltage is 30 V, the second power supply voltage is + 1V to -30V (1V step), and the electrical characteristics are the current values indicated by the ammeter 1 when the second power supply voltage is -30V. (ON current) and the current value (OFF current) indicated by the ammeter 1 when the second power supply voltage was 0FF were evaluated. In order to protect the circuit, the allowable maximum current value of the ammeter 2 is 1 mA. The results are shown in Table 2 below.

Example 5
Using a material obtained by adding 5% by mass of a precursor of the material of the following formula to the polyimide precursor in the above examples, heating was performed in an argon gas atmosphere (humidity 1% or less) with a purity of 99.99% or more, and a polyimide composition A thin film was obtained. The thin film was irradiated with UV on the source and drain electrode film forming portions, and then PEDOT / PSS was applied by inkjet as the source / drain electrode material, followed by patterning with a channel length of 5 μm. At this time, the difference in critical surface tension between the UV irradiated part and the non-irradiated part was 21 mN / m.
In addition, when an active element is manufactured in the same manner as in the above embodiment, the first power supply voltage is 30 V and the second power supply voltage is -30 V, the value of ammeter 1 is 7.9 × 10 ⁻⁶ (A). It was.

Comparative Example 3
Except that the polyimide composition of Example 5 was heated in an air atmosphere, an experiment was conducted in the same manner as in Example 5 to produce and evaluate the element. However, the element was destroyed and no measured value was obtained. .

  ADVANTAGE OF THE INVENTION According to this invention, sufficient reliability and an electronic element characteristic are obtained, the electronic element which can form a fine pattern easily at low cost, its manufacturing method, the display apparatus and arithmetic unit which have this electronic element Provided.

It is a schematic diagram when a droplet is in an equilibrium state at a contact angle θ on a solid surface. It is a figure which shows the relationship between critical surface tension (mN / m) and movement amount (cm < ² > / Vs). It is sectional drawing of the polyimide material layer which consists of a polyimide composition containing a 1st material and a 2nd material. It is sectional drawing of the polyimide material layer which consists of a polyimide composition containing the 1st material and the 2nd material which has material distribution in a film thickness direction. It is a figure for demonstrating the process of changing critical surface tension using ultraviolet irradiation. It is a figure for demonstrating the process of forming a conductive layer by the inkjet method. It is a wiring diagram of a liquid crystal display element using the electronic element of the present invention as an active element. It is an example of the arithmetic unit using the electronic element of this invention. It is an example of the arithmetic unit using the electronic element of this invention. It is a figure for demonstrating the evaluation apparatus used in the Example. It is the schematic of a MIM, MIS, and a TFT element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Solid 12 Droplet 21 Substrate 51 Substrate 52 Electrode 53 Polyamide material layer 54 Exposure mask 55 Ultraviolet ray 56 High surface energy part 57 Low surface energy part 58 Conductive layer 106,207 Gate electrode 107,205 Gate insulation film 108,206 Source electrode 109 , 207 Drain electrode 110, 208 Semiconductor layer 201 Interlayer insulating film 202 Wiring electrode 221 Second material 231 First material

Claims (9)

The electronic element having a polyimide material as an insulating material is a field effect transistor, the imidization ratio of the polyimide material is 80% or more, and the dicarboxylic acid anhydride remaining in the polyimide material is 3% or less, and The surface of the polyimide material layer has two parts, a high surface energy part with a large critical surface tension formed by applying energy and a low surface energy part with a small critical surface tension, and a part of the high surface energy part. An electronic device , wherein a conductive layer is formed on the electronic device. 2. The electronic device according to claim 1 , wherein a difference between a critical surface tension of the low surface energy portion and a critical surface tension of the high surface energy portion is 10 mN / m or more. The critical surface tension of the low surface energy part, the electronic device according to claim 1 or 2, characterized in that at most 40 mN / m. The polyimide material layer is composed of a polyimide composition including at least a first material and a second material, and the first material has a larger critical surface tension due to energy application compared to the second material. The electronic device according to claim 1 , wherein the electronic device is a material that changes, and the second material is a material having a function other than a change in wettability. Said layer of polyimide material has a distribution of the material in the film thickness direction, claim 4 in which the concentration of the first material in the outermost layer may be higher than the concentration of the second material The electronic device according to 1. Said first material, electronic device according to claim 4 or 5, characterized in that a polyimide comprising a hydrophobic group in the side chain. In the method for manufacturing an electronic device including an insulating layer having a polyimide material as an insulating material, the imidization ratio of the polyimide material is 80% or more, and the dicarboxylic acid anhydride remaining in the polyimide material is 3% or less. The insulating layer has a critical surface tension that changes due to energy application, and has two parts, a high surface energy part having a higher critical surface tension and a low surface energy part having a lower critical surface tension. A method for producing an electronic device , comprising: applying a polyimide material precursor and heating in a low-humidity environment having a humidity of 1% or less, and forming a conductive layer at a site of the high surface energy portion . 8. The method of manufacturing an electronic device according to claim 7 , wherein the application of energy for changing the critical surface tension is ultraviolet irradiation. The method for manufacturing an electronic device according to claim 7 , wherein the method for forming the conductive layer is an inkjet method.

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