JP2014056831A - Substrate for patterning organic thin film, organic electroluminescent element, organic el display device, and organic el illumination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent element low in drive voltage and capable of attaining uniform light emission, in an organic electroluminescent element using a substrate for patterning an organic thin film having a bank formed on a charge transport layer.SOLUTION: A substrate for patterning an organic thin film used for an organic electroluminescent element includes an anode layer 12, a hole injection layer, and a hole transport layer 2a, in order, on a substrate 1, and has a bank 11 and a region 8 partitioned by the bank, on the hole transport layer. A distance A from an interface between the anode layer and the hole injection layer to an interface between the hole transport layer and the bank in the region where the bank on the hole transport layer is formed is shorter than a distance B to the surface of the region partitioned by the bank on the hole transport layer. In an organic electroluminescent element, the substrate for patterning an organic thin film is used.

Description

  The present invention relates to an organic thin film patterning substrate used for an organic electroluminescent element, an organic electroluminescent element using the same, an organic EL display device, and organic EL illumination.

  In recent years, the development of organic EL displays has been remarkable, and the demand is also increasing. However, for further popularization, simplified manufacturing is required, and the inkjet process is used because the manufacturing process is simple, the yield is high, and the cost is low. Thus, a method for forming a pixel has been proposed. In the ink jet system, first, banks (partitions) for separately painting pixels are formed on a substrate to form partitioned areas, and ink for forming pixels of each of the three primary colors of RGB is ejected into the partitioned areas. A pixel is formed by drying to form an organic electroluminescent element.

However, the organic electroluminescent element must be formed in a region partitioned by a bank with a plurality of layers such as a hole injection layer and a light emitting layer, and the thickness of each layer formed in the region partitioned by the bank, etc. It was difficult to control.
Thus, for example, Patent Document 1 discloses a method of forming a hole injection layer on the entire surface of a substrate and forming a bank on the hole injection layer. According to this method, the thickness of each layer formed in the region partitioned by the bank is less likely to occur due to a simpler process than the conventional method. However, an organic electroluminescence device manufactured by forming a bank on a charge transport layer such as a hole injection layer as described above cannot obtain uniform light emission or has a high driving voltage. There was a problem.

JP 2004-234901 A

  The present invention provides a long-life organic electroluminescence device that has a low driving voltage and provides uniform light emission in an organic electroluminescence device using an organic thin film patterning substrate having a bank formed on a charge transport layer. The task is to do.

As a result of intensive studies by the present inventors, it has been found that the above problems can be solved by controlling the areas partitioned by the banks, and the present invention has been achieved. That is, the present invention provides an organic electroluminescent device having an anode layer, a hole injection layer, and a hole transport layer in this order on a substrate, and having a bank and a region partitioned by the bank on the hole transport layer. Substrate A for organic thin film patterning, wherein the hole transport layer has a distance A from the interface between the anode layer and the hole injection layer and the hole transport in the region where the bank is formed on the hole transport layer and the hole transport It exists in the organic thin film patterning board | substrate characterized by being smaller than the distance B to the surface of the area | region divided by the bank on a layer.
Moreover, this invention exists in the organic electroluminescent element formed using the said board | substrate for organic thin film patterning, an organic electroluminescent display apparatus, and organic electroluminescent illumination.

According to the present invention, in an organic electroluminescent device using an organic thin film patterning substrate having a bank formed on a charge transport layer, a driving voltage is low and uniform light emission is obtained.
In addition, a high-performance organic EL display device and organic EL illumination using such an organic electroluminescent element can be obtained.

It is typical sectional drawing which shows the structure of the board | substrate for organic thin film patterning. It is typical sectional drawing which shows the embodiment of the manufacturing procedure of the organic thin film patterning board | substrate, and the formation process of the organic thin film to the manufactured organic thin film patterning board | substrate.

The description of the constituent requirements described below is an example (representative example) of the embodiment of the present invention, and the contents are not specified.
<Organic thin film patterning substrate>
The organic thin film patterning substrate of the present invention has an electrode layer and a charge transport layer in this order on a substrate, and has a bank and a region partitioned by the bank on the charge transport layer. A thin film patterning substrate, wherein the distance A from the interface between the electrode layer and the charge transport layer to the interface between the charge transport layer and the bank in the region where the bank on the charge transport layer is formed, and the bank on the charge transport layer The distance B to the surface of the area partitioned by is different.

A schematic cross-sectional view of the organic thin film patterning substrate of the present invention is shown in FIG. The distance A to the interface between the charge transport layer and the bank may be different from the distance B to the surface of the region partitioned by the bank on the charge transport layer. The distance B may be larger than B, or the distance B may be larger than the distance A as shown in FIG.
The reason why the effects of the present invention are achieved when the distance A and the distance B are different is estimated as follows.

That is, an element having a low driving voltage, a high light emission efficiency, and a long lifetime can be provided by an element having an optimized element structure with respect to the employed material system. Here, the element structure refers to the layer structure of the adopted material system, the layer thickness and composition of the constituent layers, the doping amount in each layer, and the like.
The distance B corresponds to, for example, the thickness of the charge transport layer in the light emitting region. This thickness is a parameter that has a great influence on the element characteristics, drive voltage, charge injection efficiency, light emission efficiency, and the like. Therefore, in the conventional structure, if the distance A is determined to be different from the optimum value for the device characteristics in the process in which the distance A is determined, the final process is reached without shifting, and the device is optimal as a result. The result is a non-value, and the device characteristics deviate from the optimum values.

Therefore, according to the present invention, even if the distance A deviates from the optimum value, the distance B can be set to the optimum value by setting the distance B adjusted in the subsequent process of determining the distance A.
Further, for example, in the RGB full-color organic EL display device, even when the optimum thickness of the charge transport layer varies depending on the type of the light emitting layer, each light emitting layer can be obtained by setting the distance B to the optimum film thickness according to each light emitting layer. It is possible to optimize the element characteristics according to the type.

Therefore, according to the present invention, it is presumed that such an effect makes it possible to provide an element having a low driving voltage, a high light emission efficiency, and a long lifetime.
The distance A and the distance B will be described using the cross-sectional view of the patterning substrate shown in FIG.
The distance A represents the distance from the interface between the electrode layer and the charge transport layer to the interface between the charge transport layer and the bank in the region where the bank is formed on the charge transport layer.
The distance B represents the distance from the interface between the electrode layer and the charge transport layer to the surface of the region partitioned by the bank on the charge transport layer.

The interface between the electrode layer and the charge transport layer, the interface between the charge transport layer and the bank, and the surface of the region partitioned by the bank on the charge transport layer are defined as follows.
The interface between the electrode layer and the charge transport layer is defined as the substance interface between the constituents of the electrode layer and the constituents of the charge transport layer (a set of points where the physical quantity depending on the type of substance or the type of substance changes sharply Defined as a three-dimensional curved surface having a mathematical form in which one constraint is given to the three degrees of freedom of the three-dimensional space. Here, “steeply changing” usually means changing on a scale having a length of 1000 times or less, preferably 10 times or less the size of an atom as a minimum unit constituting a substance. Specifically, it can be said that if the type of substance or the related physical quantity changes within a length of several nanometers or less, it changes abruptly. However, as a method of defining “a sharply changing point” within a finite length, a spatial point that gives an average value of values before and after the abrupt change is usually performed for the physical quantity of interest. .

  Next, consider a method for determining the type of substance, or a method for determining the physical quantity, for example, density, or another physical quantity as a function of density, for example, refractive index or elastic modulus. In general, the type of material can be measured from spectroscopic measurements, the refractive index from optical measurements, and the elastic modulus from mechanical measurements. By applying these measurement methods and determining the set of points that change sharply, the interface between the electrode layer and the charge transport layer can be defined.

The interface between the charge transport layer and the bank is defined as the interface between the charge transport layer and the bank.
Even before or after the bank is developed, the interface between the charge transport layer and the bank can be determined according to the above method.
The region surface defined by the bank on the charge transport layer is a region that is exposed as a surface even if the charge transport layer is partially. Here, the surface refers to a boundary between a substance and an atmosphere or a vacuum.

  Based on such a definition, a specific method for measuring each of the interfaces by detecting a change in another physical property caused by a change in the type of a substance and a physical quantity associated therewith is a transmission electron microscope (TEM). And a scanning probe microscope (SPM), and a method of combining them with a spectroscopic measurement method such as Auger electron spectroscopy and X-ray fluorescence spectroscopy. In addition, a method combining secondary ion mass spectrometry (SIMS) and ion time-of-flight analysis, spectroscopic ellipsometry (spectral ellipsometry), optical interference surface shape measuring method (VertScan, manufactured by Ryoka Systems Inc.), stylus Examples include an optical lever type surface shape measuring method.

Next, a method for determining the distance A by determining the interface between the charge transport layer and the bank using such a measurement method will be described.
First, an example of a method for measuring the surface shape of the electrode layer surface before forming the charge transport layer by the surface shape measurement method will be described. Here, the surface shape refers to a one-dimensional or two-dimensional distribution of the relative height of the surface. In addition, a distance obtained from the one-dimensional or two-dimensional distribution is set as distance A or distance B. Further, the distance may be simply expressed as a length. The resolution of the relative length and distance depends on the accuracy and resolution of the measurement method and measurement device.

  For the reference point for the relative height, a position where reproducibility can be consistently selected is selected. For example, a specified point in the surface of the electrode surface of the substrate is aligned with the origin of the measuring table surface of the measuring instrument, and the electrode surface is used as a reference for a planar position (referred to as a reference position). be able to. Regarding the designation of the reference position, it is preferable to provide an alignment mark or the like so that it can be clearly distinguished from other points in consideration of the resolution of the length.

  The measured electrode surface shape is recorded, and then a charge transport layer is formed. The surface shape of the formed charge transport layer is similarly measured. With respect to the relative value (difference) of the charge transport layer surface shape to the recorded electrode surface shape, the distance between the surface of the charge transport layer and the interface between the electrode layer and the charge transport layer at the reference position, that is, the distance A If the absolute value of the corresponding distance is added, the distance corresponding to the distance A can be determined.

Therefore, in order to measure the absolute value of the distance corresponding to the distance A at the reference position, the above method, for example, TEM, SPM or SIMS, spectroscopic ellipsometer, VertScan, stylus optical lever type surface shape measuring method, etc. Can be used.
In order to actually obtain a value corresponding to the distance A at the reference position, a method of extracting a cross section at the reference position and performing elemental analysis mapping using, for example, TEM or the like can be employed.

  However, if it is difficult to obtain a cross-section of the product at the actual manufacturing site, for example, a dummy substrate that is not made into a product is flowed together, and the cross-section is measured on the dummy substrate, or the manufacturing conditions at the condition determination stage And the value corresponding to the distance A may be determined by a method such as taking a correlation between the distance A and the value corresponding to the distance A. If the manufacturing conditions are not stable, a sampling inspection may be performed.

In this way, the surface shape of the electrode surface and the surface shape of the charge transport layer are measured in a state where the reference positions are matched, and the thickness of the charge transport layer at the reference position is measured, thereby corresponding to the distance A. It was stated that the distribution of distances can be determined.
However, the distribution may be a distance corresponding to the distance A. Further, the distance from the surface where the charge transport layer is exposed after the bank formation to the interface between the charge transport layer and the electrode layer may be measured as a distance corresponding to the distance A.

Further, although a bank formation process exists after this, if the interface changes through the process, the distance A is not yet set. In this case, measurement is performed to determine the distance A after all the bank forming steps are completed, or the amount by which the distance A changes before and after the bank forming step is taken into account. Good.
Regarding the distance B, the measurement itself can be measured by the same method as the distance A. Furthermore, more simply, by taking the surface of the formed bank as a reference, a distance distribution corresponding to a relative value (distance A−distance B) is measured, and the distribution corresponding to the distance A It is also possible to calculate a distribution corresponding to the distance B from the difference. In this case, it is only necessary to confirm and take into account the amount of change in the distance from the bank surface at the reference position to the electrode layer surface or the interface between the charge transport layer and the electrode layer through each step.

A method for comparing a plurality of surface shapes (for example, a distribution corresponding to the distance A and a distribution corresponding to the distance B) will be described below.
This problem results in a test problem that asks whether the two distributions are the same or different. Therefore, for the distribution of values corresponding to the distance A and the distance B, the maximum likelihood value is calculated using statistical processing and is compared.

Therefore, in the present invention, the one-dimensional or two-dimensional distribution itself is not set as the distance A and the distance B, but the maximum likelihood value (usually an average) calculated by performing appropriate statistical processing on the distribution. The average value calculated by performing the conversion process) is defined as distance A and distance B.
At this time, by not forming the charge transport layer at the reference position, or by removing the formed charge transport layer, only by measuring the surface shape including the reference position where the charge transport layer is not present, Since it is possible to estimate the thickness (maximum likelihood value) of the charge transport layer at a specified point in the plane of the electrode surface, measurement is simple and preferable.

Furthermore, if the relative value of (distance A−distance B) can be measured, there is no need to measure distance A and distance B, respectively. With such relative measurement, it is also possible to measure a relative value (distance A−distance B) with the bank upper surface at the reference position as the reference height.
The distance B is determined depending on how close the distance A is to the optimum design value. That is, as long as the distance B is the optimum design value, the distance A may take any value, and the degree of freedom can be increased in designing the manufacturing process.

As an example of the optimum design value of the thickness of the charge transport layer, 40 nm can be cited. However, when the distance B is 40 nm, the distance A selects a different value that is most effective in the entire manufacturing process. be able to.
Thus, the following methods are mentioned as a method of manufacturing the organic thin film patterning substrate so that the distance A and the distance B are different.
(1) A method of peeling a part of the surface of the charge transport layer in a region partitioned by the bank after forming the bank on the charge transport layer
(2) A method of forming a bank on the charge transport layer, and then peeling a part or all of the surface of the charge transport layer in a region partitioned by the bank, and then depositing a charge transport material on the peel region
(3) A method of forming a charge transport material in a region partitioned by a bank after forming a bank on the charge transport layer
(4) A method of peeling a part of the surface of the charge transport layer after forming a bank on the charge transport layer, forming a charge transport material in a region partitioned by the bank
The organic thin film patterning substrate of the present invention has an electrode layer and one or more charge transport layers in this order on the substrate, and has a bank and a region partitioned by the bank on the charge transport layer. However, it is sufficient that the substrate, the electrode layer, and the charge transport layer are formed in this order, and other layers may be provided between them, but it is preferable that they are formed adjacent to each other. . Specific examples of the substrate, the electrode layer, and the charge transport layer will be described in detail below. The electrode layer may be an anode, a cathode, a single layer, or a laminated structure. It may consist of. In addition, the charge transport layer may have at least one layer, and two or more layers may be laminated. Usually, it is preferable that two or more charge transport layers are laminated.

Further, the organic thin film patterning substrate of the present invention comprises a material constituting the charge transport layer at the interface between the charge transport layer and the bank in the region where the bank is formed, and a charge transport layer on the surface of the region partitioned by the bank The material to be transported does not have a step of ionization potential or electron affinity of the charge transport material in the charge transport layer when the charge is transported, that is, adds a special electric resistance in the charge transport layer. It is preferable that the charge is transported without any problem, and the charge transport is such that the step of ionization potential or electron affinity that the charge feels when the charge is injected from the charge transport layer to the light emitting layer is reduced as much as possible. It is preferred that they differ in the choice of material for forming the layer.
Note that the same material means the same composition.
Hereinafter, the organic thin film patterning substrate of the present invention will be described taking the methods (1) and (3) as examples. First, the process up to forming a bank on the charge transport layer, which is common to the methods (1) and (3), will be described.

<Formation of charge transport layer>
Referring to FIG. 2, an anode is formed as an electrode layer on a substrate, a hole injection layer (FIG. 2A) is formed as a first charge transport layer, and a hole transport layer is formed as a second charge transport layer ( 2B), an organic thin film patterning substrate having a bank formed on the second charge transport layer will be described as an example. However, the present invention is not limited to this (note that FIG. (The distance A and the distance B are the same in the drawing.) In the present invention, as described above, the charge transport layer may be other than the hole injection layer or the hole transport layer, may be composed of one layer, or is formed by laminating three or more layers. It may be. The electrode layer may be a cathode.

(substrate)
As the substrate, quartz or glass plate, metal plate, metal foil, plastic film, sheet or the like is used. In particular, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, polysulfone or the like is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic electroluminescent element may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

(anode)
The anode is usually a metal such as aluminum, gold, silver, nickel, palladium, or platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or poly ( 3-methylthiophene), polypyrrole, polyaniline and other conductive polymers.

  The anode is usually formed by a sputtering method, a vacuum deposition method, or the like. In addition, when forming an anode using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, an appropriate binder resin solution is used. The anode can also be formed by dispersing and coating the substrate. Further, in the case of a conductive polymer, a thin film can be directly formed on a substrate by electrolytic polymerization, or an anode can be formed by applying a conductive polymer on a substrate (Appl. Phys. Lett. , 60, 2711, 1992).

The anode usually has a single-layer structure, but it can also have a laminated structure composed of a plurality of materials if desired.
The thickness of the anode depends on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably about 500 nm or less. When opaqueness is acceptable, the thickness of the anode is arbitrary, and the anode may be integrated with the substrate. Furthermore, different conductive materials may be laminated.

The surface of the anode is treated with ultraviolet (UV) / ozone, oxygen plasma, or argon plasma for the purpose of removing impurities adhering to the anode and adjusting the ionization potential to improve hole injection. Is preferred.
When an organic electroluminescent element is produced by forming an organic thin film on a patterned anode on the substrate, element degradation at the edge of the anode is one of the problems. Such element deterioration appears remarkably in a portion where the edge portion faces a cathode described later. The reason for this is that the relationship between the local electric field strength applied to the organic thin film sandwiched between the anode and the cathode and the current density is extremely different at the edge compared to the central flat portion. In other words, the increase in electric field strength resulting from the special shape of the cross-sectional shape (existence of a step) and the accompanying increase in current density at the edge promote the deterioration of the materials that make up the organic thin film locally, and thus the device lifetime. Results in further shortening.

One way to solve this problem is to place an insulating film on the anode, cover the edge,
A method of forming an opening through which a current flows by patterning a region to emit light is known, and an insulating thin film having such an opening is generally referred to as an “opening insulating film”. By doing so, it is possible to eliminate the electric field concentration resulting from the shape speciality of the edge portion and to distribute the electric field uniformly from the anode to the cathode.

As the insulating film, a silicon dioxide thin film is generally used. Alternatively, an organic thin film typified by a silicon oxynitride thin film or a polyimide thin film can also be used.
As a patterning method, a photolithography method is generally used. As a method for forming the opening, an ion milling method, a wet etching method, or the like is used in addition to the reactive ion etching method.

Furthermore, it is preferable that the surface after the opening is formed and the anode is exposed is subjected to ultraviolet (UV) / ozone treatment or oxygen plasma or argon plasma treatment.
However, the formation of such an opening insulating film increases the number of element manufacturing steps, and has an effect on a decrease in yield and an increase in manufacturing cost. One method for making this possible is to use the bank as an opening insulating film. This can be realized by designing the bank so as to cover the edge of the anode as a planar shape.
In particular, when a bank is formed after the charge transport layer is formed over the entire surface of the substrate, the bank functions more effectively as an opening insulating film.

(Hole injection layer)
The hole injection layer is formed on the entire surface of the anode (in the present invention, the entire surface means the entire surface and almost the entire surface) (FIG. 2A).
The method for forming the hole injection layer according to the present invention may be a vacuum vapor deposition method or a wet film formation method, and is not particularly limited. However, from the viewpoint of reducing dark spots, the hole injection layer may be formed by a wet film formation method. preferable. The thickness of the hole injection layer is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

(Formation of hole injection layer by wet film formation method)
When the hole injection layer is formed by wet film formation, the material for forming the hole injection layer is usually mixed with an appropriate solvent (hole injection layer solvent) to form a composition for film formation (hole injection). A composition for forming a layer) is prepared, and this composition for forming a hole injection layer is coated on the anode by an appropriate technique to form a film and dried to form a hole injection layer.
Here, the wet film forming method in the present invention is, for example, a spin coating method, a dip coating method, a die coating method, a bar coating method, a blade coating method, a roll coating method, a spray coating method, a capillary coating method, an ink jet method, a screen. A wet film formation method such as a printing method, a gravure printing method, or a flexographic printing method.

(Hole transporting compound)
The composition for forming a hole injection layer usually contains a hole transporting compound and a solvent as constituent materials of the hole injection layer.
The hole transporting compound is a compound having a hole transporting property that is usually used in a hole injection layer of an organic electroluminescence device, and may be a polymer compound or the like, a monomer or the like. Although it may be a low molecular weight compound, it is preferably a high molecular weight compound.
The hole transporting compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of a charge injection barrier. Examples of hole transporting compounds include aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, compounds in which tertiary amines are linked by a fluorene group, hydrazone derivatives, silazane derivatives, silanamines Derivatives, phosphamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, carbon and the like.

In the present invention, the derivative includes, for example, an aromatic amine derivative, and includes an aromatic amine itself and a compound having an aromatic amine as a main skeleton. It may be a mer.
The hole transporting compound used as the material for the hole injection layer may contain any one of these compounds alone, or may contain two or more. When two or more hole transporting compounds are contained, the combination thereof is arbitrary, but one or more aromatic tertiary amine polymer compounds and one or two other hole transporting compounds are used. It is preferable to use the above in combination.

Among the above examples, an aromatic amine compound is preferable from the viewpoint of amorphousness and visible light transmittance, and an aromatic tertiary amine compound is particularly preferable. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine.
The type of the aromatic tertiary amine compound is not particularly limited, but from the viewpoint of uniform light emission due to the surface smoothing effect, a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less (a polymerizable compound in which repeating units are linked) is further included. preferable. Preferable examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following formula (I).

(In Formula (I), Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Ar ^{3 to} Ar ⁵ each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Represents a linking group selected from the group of linking groups, and among Ar ^{1 to} Ar ⁵ , two groups bonded to the same N atom may be bonded to each other to form a ring.

(In the above formulas, Ar ^{6 to} Ar ¹⁶ each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. R ¹ and R ² each independently represents a hydrogen atom or an arbitrary substituent.))
As the aromatic hydrocarbon group and the aromatic heterocyclic group of Ar ^{1 to} Ar ¹⁶ , a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene from the viewpoint of the solubility, heat resistance, hole injection / transport property of the polymer compound A group derived from a ring or a pyridine ring is preferred, and a group derived from a benzene ring or a naphthalene ring is more preferred.

The aromatic hydrocarbon group and aromatic heterocyclic group of Ar ^{1 to} Ar ¹⁶ may further have a substituent. The molecular weight of the substituent is usually 400 or less, preferably about 250 or less. As the substituent, an alkyl group, an alkenyl group, an alkoxy group, an aromatic hydrocarbon group, an aromatic heterocyclic group and the like are preferable.
When R1 and R2 are optional substituents, examples of the substituent include an alkyl group, an alkenyl group, an alkoxy group, a silyl group, a siloxy group, an aromatic hydrocarbon group, and an aromatic heterocyclic group.

Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by the formula (I) include those described in International Publication No. 2005/089024.
In addition, as a hole transporting compound, a conductive polymer (PEDOT / PSS) obtained by polymerizing 3,4-ethylenedioxythiophene (3,4-ethylenedioxythiophene), a polythiophene derivative, in high molecular weight polystyrene sulfonic acid. Is also preferred. Moreover, the end of this polymer may be capped with methacrylate or the like.

  The concentration of the hole transporting compound in the composition for forming a hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.01% by weight or more, preferably in terms of film thickness uniformity. Is 0.1% by weight or more, more preferably 0.5% by weight or more, and usually 70% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. If this concentration is too high, film thickness unevenness may occur, and if it is too low, defects may occur in the formed hole injection layer.

(Electron-accepting compound)
The composition for forming a hole injection layer preferably contains an electron accepting compound as a constituent material of the hole injection layer.
The electron-accepting compound is preferably a compound having an oxidizing power and the ability to accept one electron from the above-described hole transporting compound, specifically, a compound having an electron affinity of 4 eV or more is preferable, and 5 eV or more. The compound which is the compound of these is further more preferable.

Examples of such electron-accepting compounds include triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. Examples thereof include one or more compounds selected from the group. More specifically, an onium salt substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate or triphenylsulfonium tetrafluoroborate (WO 2005/089024) A high-valent inorganic compound such as iron (III) chloride (Japanese Patent Laid-Open No. 11-251067) and ammonium peroxodisulfate; a cyano compound such as tetracyanoethylene; Aromatic boron compounds; fullerene derivatives; iodine; sulfonate ions such as polystyrene sulfonate ions, alkylbenzene sulfonate ions, camphor sulfonate ions, and the like.

These electron accepting compounds can improve the conductivity of the hole injection layer by oxidizing the hole transporting compound.
The content of the electron-accepting compound in the hole-injecting layer or the composition for forming a hole-injecting layer with respect to the hole-transporting compound is usually 0.1 mol% or more, preferably 1 mol% or more. However, it is usually 100 mol% or less, preferably 40 mol% or less.

(Other components)
As a material for the hole injection layer, other components may be further contained in addition to the above-described hole transporting compound and electron accepting compound as long as the effects of the present invention are not significantly impaired. Examples of other components include various light emitting materials, electron transporting compounds, binder resins, and coating property improving agents. In addition, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.

(solvent)
At least one of the solvents of the composition for forming a hole injection layer used in the wet film formation method is preferably a compound that can dissolve the constituent material of the hole injection layer. The boiling point of this solvent is usually 110 ° C. or higher, preferably 140 ° C. or higher, particularly 200 ° C. or higher, usually 400 ° C. or lower, and preferably 300 ° C. or lower. If the boiling point of the solvent is too low, the drying speed is too high and the film quality may be deteriorated. Further, if the boiling point of the solvent is too high, it is necessary to increase the temperature of the drying step, which may adversely affect other layers and the substrate.

Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, and the like.
Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole , Phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, aromatic ethers such as 2,4-dimethylanisole, and the like.

Examples of the ester solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.
Examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylpropylphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene. Can be mentioned.
Examples of the amide solvent include N, N-dimethylformamide, N, N-dimethylacetamide, and the like.

In addition, dimethyl sulfoxide and the like can also be used.
These solvent may use only 1 type and may use 2 or more types by arbitrary combinations and a ratio.

(Film formation method)
After preparing the composition for forming a hole injection layer, the composition is formed on the anode by wet film formation and dried to form a hole injection layer.
The temperature in the film forming step is preferably 10 ° C. or higher, and preferably 50 ° C. or lower, in order to prevent film loss due to the formation of crystals in the composition.

Although the relative humidity in a film-forming process is not limited unless the effect of this invention is impaired remarkably, it is 0.01 ppm or more normally and 80% or less normally.
After the film formation, the film of the composition for forming a hole injection layer is usually dried by heating or the like. Examples of the heating means used in the heating step include a clean oven, a hot plate, infrared rays, a halogen heater, microwave irradiation and the like. Among them, a clean oven and a hot plate are preferable in order to uniformly apply heat to the entire film.

The heating temperature in the heating step is preferably heated at a temperature equal to or higher than the boiling point of the solvent used in the composition for forming a hole injection layer as long as the effects of the present invention are not significantly impaired. In the case of a mixed solvent containing two or more types of solvents used in the hole injection layer, at least one type is preferably heated at a temperature equal to or higher than the boiling point of the solvent. In consideration of an increase in the boiling point of the solvent, the heating step is preferably performed at 120 ° C. or higher, preferably 410 ° C. or lower.

  In the heating step, the heating time is not limited as long as the heating temperature is not lower than the boiling point of the solvent of the composition for forming a hole injection layer and sufficient insolubilization of the coating film does not occur. Is less than a minute. If the heating time is too long, the components of the other layers tend to diffuse, and if it is too short, the hole injection layer tends to be inhomogeneous. Heating may be performed in two steps.

(Formation of hole injection layer by vacuum evaporation)
When the hole injection layer is formed by vacuum deposition, one or more of the constituent materials of the hole injection layer (the aforementioned hole transporting compound, electron accepting compound, etc.) are placed in a vacuum vessel. Put in crucibles (in case of using two or more kinds of materials, put them in each crucible), evacuate the inside of the vacuum vessel to about 10 ⁻⁴ Pa with a suitable vacuum pump, When using materials, heat each crucible) and evaporate by controlling the amount of evaporation (when using two or more materials, evaporate by controlling the amount of evaporation independently) and place it facing the crucible. A hole injection layer is formed on the anode of the substrate. In addition, when using 2 or more types of materials, those hole mixture layers can also be formed by putting them in a crucible and heating and evaporating them.

The degree of vacuum at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 × 10 ⁻⁶ Torr (0.13 × 10 ⁻⁴ Pa) or more, usually 9.0 × 10 ⁻⁶ Torr. (12.0 × 10 ⁻⁴ Pa) or less. The deposition rate is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 Å / second or more and usually 5.0 Å / second or less. The film forming temperature at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 10 ° C. or higher, preferably 50 ° C. or lower.

  The hole injection layer may be formed using a material for a hole transport layer described below. For example, a polyarylamine derivative or a polyarylene derivative as described in detail below may be used as the hole transporting compound, or a crosslinkable compound may be used. Moreover, you may use the compound which has a functional group dissociated with a heat | fever or an active energy ray. The active energy ray will be described later.

(Hole transport layer)
A hole transport layer is formed on the entire surface of the hole injection layer (FIG. 2B).
The formation method of the hole transport layer according to the present invention may be a vacuum deposition method or a wet film formation method, and is not particularly limited, but the hole transport layer may be formed by a wet film formation method from the viewpoint of reducing dark spots. preferable.
The material for forming the hole transport layer is preferably a material having high hole transportability and capable of efficiently transporting injected holes. Therefore, it is preferable that the ionization potential is small, the transparency to visible light is high, the hole mobility is large, the stability is high, and impurities that become traps are not easily generated during manufacturing or use.

  As a material of such a hole transport layer, any material that has been conventionally used as a constituent material of a hole transport layer may be used. For example, as a hole transport compound used in the above-described hole injection layer What was illustrated is mentioned. In addition, arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, condensed polycyclic aromatics Group derivatives, metal complexes and the like.

  In addition, for example, polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylene derivatives, polysiloxane derivatives, polythiophenes Derivatives, poly (p-phenylene vinylene) derivatives, and the like. These may be any of an alternating copolymer, a random polymer, a block polymer, or a graft copolymer. Further, it may be a polymer having a branched main chain and three or more terminal portions, or a so-called dendrimer.

Of these, polyarylamine derivatives and polyarylene derivatives are preferred.
The polyarylamine derivative is preferably a polymer containing a repeating unit represented by the following formula (II). In particular, a polymer composed of a repeating unit represented by the following formula (II) is preferable. In this case, Ar ^a or Ar ^b may be different in each repeating unit.

(In Formula (II), Ar ^a and Ar ^b each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent.)
Examples of the aromatic hydrocarbon group which may have a substituent include, for example, a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, and acenaphthene. Examples thereof include a group derived from a 6-membered monocyclic ring or a 2-5 condensed ring, such as a ring, a fluoranthene ring, and a fluorene ring, and a group in which two or more of these rings are linked by a direct bond.

  Examples of the aromatic heterocyclic group which may have a substituent include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, and a carbazole ring. , Pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine Ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, etc. Or a group and the rings of from 2-4 fused rings include groups formed by connecting a direct bond or two or more rings.

From the viewpoints of solubility and heat resistance, Ar ^a and Ar ^b are each independently selected from the group consisting of a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, triphenylene ring, pyrene ring, thiophene ring, pyridine ring, and fluorene ring. A group derived from a selected ring or a group formed by linking two or more benzene rings (for example, a biphenyl group or a terphenyl group) is preferable.
Among these, a group derived from a benzene ring (phenyl group), a group formed by connecting two benzene rings (biphenyl group), and a group derived from a fluorene ring (fluorenyl group) are preferable.

Examples of the substituent for Ar ^a and Ar ^b include an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, a dialkylamino group, a diarylamino group, an acyl group, a halogen atom, a haloalkyl group, and an alkylthio group. Arylthio group, silyl group, siloxy group, cyano group, aromatic hydrocarbon ring group, aromatic heterocyclic group and the like.

As the polyarylene derivative, an arylene group such as an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent exemplified as Ar ^a or Ar ^b in the formula (II) is used as its repeating unit. The polymer which has is mentioned.
As a polyarylene derivative, the polymer which has a repeating unit which consists of following formula (III-1) and / or following formula (III-2) is preferable.

(In formula (III-1), R ^a , R ^b , R ^c and R ^d are each independently an alkyl group, an alkoxy group, a phenylalkyl group, a phenylalkoxy group, a phenyl group, a phenoxy group, an alkylphenyl group, Represents an alkoxyphenyl group, an alkylcarbonyl group, an alkoxycarbonyl group, or a carboxy group, and t and s each independently represent an integer of 0 to 3. When t or s is 2 or more, they are contained in one molecule. A plurality of R ^a or R ^b may be the same or different, and adjacent R ^a or R ^b may form a ring.)

(In Formula (III-2), R ^e and R ^f are each independently the same as R ^a , R ^b , R ^c or R ^d in Formula (III-1) above. Independently, it represents an integer of 0 to 3. When r or u is 2 or more, a plurality of R ^e and R ^f contained in one molecule may be the same or different, and adjacent R ^e or R ^f may form a ring, and X represents an atom or a group of atoms constituting a 5-membered ring or a 6-membered ring.)
Specific examples of X include an oxygen atom, a boron atom which may have a substituent, a nitrogen atom which may have a substituent, a silicon atom which may have a substituent, and a substituent. A phosphorus atom which may be substituted, a sulfur atom which may have a substituent, a carbon atom which may have a substituent, or a group formed by bonding these.

  Further, the polyarylene derivative has a repeating unit represented by the following formula (III-3) in addition to the repeating unit consisting of the formula (III-1) and / or the formula (III-2). Is preferred.

(In the formula (III-3), Ar ^{c to} Ar ^j each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent. Independently represents 0 or 1.)
Specific examples of Ar ^{c to} Ar ^j are the same as Ar ^a and Ar ^b in the formula (II).

Specific examples of the above formulas (III-1) to (III-3) and specific examples of polyarylene derivatives include those described in JP-A-2008-98619.
When the hole transport layer is formed by a wet film formation method, a composition for forming a hole transport layer is prepared in the same manner as the formation of the hole injection layer, followed by heat drying after the wet film formation.
The composition for forming a hole transport layer contains a solvent in addition to the above hole transport compound. The solvent used is the same as that used for the composition for forming a hole injection layer. The film forming conditions, heat drying conditions, and the like are the same as in the case of forming the hole injection layer.

In the case where the hole transport layer is formed by the vacuum deposition method, the film forming conditions are the same as in the case of forming the hole injection layer.
The hole transport layer may contain various light emitting materials, electron accepting compounds, electron transporting compounds, binder resins, coatability improving agents, and the like in addition to the above hole transporting compounds.
The hole transport layer may also be a layer formed by crosslinking a crosslinkable compound. The crosslinkable compound is a compound having a crosslinkable group, and forms a network polymer compound by crosslinking.

Examples of this crosslinkable group include groups derived from cyclic ethers such as oxetane and epoxy; groups derived from unsaturated double bonds such as vinyl, trifluorovinyl, styryl, acrylic, methacryloyl and cinnamoyl; benzo Examples include groups derived from cyclobutene.
The crosslinkable compound may be any of a monomer, an oligomer, and a polymer. The crosslinkable compound may have only 1 type, and may have 2 or more types by arbitrary combinations and ratios.

  As the crosslinkable compound, a hole transporting compound having a crosslinkable group is preferably used. Examples of the hole transporting compound include those exemplified above, and those having a crosslinkable group bonded to the main chain or side chain with respect to these hole transporting compounds. In particular, the crosslinkable group is preferably bonded to the main chain via a linking group such as an alkylene group. In particular, the hole transporting compound is preferably a polymer containing a repeating unit having a crosslinkable group, and the above formula (II) and formulas (III-1) to (III-3) can be used as a crosslinkable group. Is preferably a polymer having a repeating unit bonded directly or via a linking group.

  As the crosslinkable compound, a hole transporting compound having a crosslinkable group is preferably used. Examples of hole transporting compounds include nitrogen-containing aromatic compound derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives, phthalocyanine derivatives, porphyrin derivatives; triphenylamine derivatives Silole derivatives; oligothiophene derivatives, condensed polycyclic aromatic derivatives, metal complexes and the like. Among them, nitrogen-containing aromatic derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives; triphenylamine derivatives, silole derivatives, condensed polycyclic aromatic derivatives, metal complexes, etc. Particularly preferred are triphenylamine derivatives.

In order to form a hole transport layer by crosslinking a crosslinkable compound, a composition for forming a hole transport layer in which a crosslinkable compound is dissolved or dispersed in a solvent is usually prepared and formed by wet film formation. Crosslink.
The composition for forming a hole transport layer may contain an additive for promoting a crosslinking reaction in addition to the crosslinking compound. Examples of additives that accelerate the crosslinking reaction include polymerization initiators and polymerization accelerators such as alkylphenone compounds, acylphosphine oxide compounds, metallocene compounds, oxime ester compounds, azo compounds, onium salts; condensed polycyclic hydrocarbons, And photosensitizers such as porphyrin compounds and diaryl ketone compounds.

Further, it may contain a coating property improving agent such as a leveling agent and an antifoaming agent; an electron accepting compound; a binder resin;
In the composition for forming a hole transport layer, the crosslinkable compound is usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, usually 50% by weight or less, preferably 20%. It is contained in an amount of not more than wt%, more preferably not more than 10 wt%.

After forming a composition for forming a hole transport layer containing a crosslinkable compound at such a concentration on the hole injection layer, the crosslinkable compound is crosslinked by heating and / or irradiation with active energy such as light to form a network. Form a polymer compound.
Conditions such as temperature and humidity during film formation are the same as those during wet film formation of the hole injection layer.
The heating method after film formation is not particularly limited. As heating temperature conditions, it is 120 degreeC or more normally, Preferably it is 400 degrees C or less.

The heating time is usually 1 minute or longer, preferably 24 hours or shorter. The heating means is not particularly limited, and means such as placing a laminated body having a deposited layer on a hot plate or heating it in an oven is used. For example, conditions such as heating on a hot plate at 120 ° C. or more for 1 minute or more can be used.
In the case of irradiation with active energy rays, the active energy rays are energy rays that give energy to chemical bonds of compounds and can change the bonds themselves or higher-order structures of the compounds, such as infrared rays and visible rays. Examples thereof include light rays, ultraviolet rays, X-rays, gamma rays resulting from decay of radioactive isotopes, electron beams, ion beams, neutral atom beams, and other elementary particle beams such as proton beams, neutron beams, and positron beams. There are various generation methods and irradiation methods. For example, if it is a source of energy rays, magnetron, ultra high pressure mercury lamp, high pressure mercury lamp, halogen lamp, infrared lamp, LED light source, laser light source, etc. There are X-ray sources that irradiate rays, gamma ray sources due to decay of radioisotopes, synchrotron (radiation light), high-voltage electron beam sources obtained by accelerating thermionic electrons at a high voltage, FIB (focused ion beam), etc. As a method, it is also possible to directly irradiate from a light source, scan an active energy ray converged in a narrow region and irradiate a wide region, or expand an active energy ray to a wide region and irradiate simultaneously.

More specifically, a method of irradiating directly using the above-described ultraviolet / visible / infrared light source, a method of irradiating using a mask aligner or a conveyor-type light irradiating device incorporating the above-mentioned light source, and the like can be mentioned. In active energy irradiation other than light, for example, there is a method of irradiation using a so-called microwave oven that irradiates a microwave generated by a magnetron.
As conditions, the type and central energy of irradiation are selected according to the target compound, and the irradiation region and time are appropriately selected according to the element structure and film thickness. Preferably, the radiation source and irradiation energy / time are selected in accordance with the binding energy of the bond to be changed. As a normal irradiation time, it is preferable to set conditions for obtaining a necessary and sufficient degree of cross-linking, but the irradiation is performed for 0.1 second or longer, preferably 10 hours or shorter.

You may perform heating and irradiation of active energy rays, such as light, individually or in combination. When combined, the order of implementation is not particularly limited.
The film thickness of the hole transport layer thus formed is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

<Bank formation>
A bank is formed on the hole transport layer. The method for forming the bank is not particularly limited, but it is preferably formed by a photolithography method, and a bank is formed by forming a photosensitive composition on the hole transport layer, and then exposing and developing. It is preferable to do. In addition, after the development, if a residue of the photosensitive composition remains in the area partitioned by the bank, it may affect the light emission when the organic electroluminescence device is formed. Therefore, the photosensitive composition is formed into a film. Before forming a hydrophilic compound-containing composition and forming an undercoat layer (FIG. 2C), a photosensitive composition is formed thereon (FIG. 2D), and is preferably subjected to exposure and development ( FIG. 2E). Thereby, a bank becomes a laminated structure of the undercoat layer formed with a hydrophilic compound containing composition and the resin layer formed with a photosensitive composition (FIG. 2F). As described above, the bank may be a laminate including two layers or three or more layers, or may be a single layer without an undercoat layer.

(Underlayer)
First, the undercoat layer formed using the hydrophilic compound-containing composition will be described. The hydrophilic compound-containing composition contains a hydrophilic compound and usually further contains a solvent.
Hereinafter, in the present invention, “(meth) acrylic acid” means including both “acrylic acid” and “methacrylic acid”, and includes “(meth) acrylate”, “(meth) acryloyl”, and the like. Has the same meaning. The term “(poly)” in front of the monomer name means that both the “monomer” and the “polymer” are included, and “acid (anhydride)”, “(anhydrous)” are included. ... "Acid" means to include both "acid" and its "acid anhydride". Further, the “acid (salt) group” means that both an “acid group” and its “base” are included. “(Co) polymerization” means to include both “polymerization” and “copolymerization”. In the present invention, the “total solid content” means all components excluding the solvent among the constituent components of the composition.

Moreover, in this invention, the molecular weight of various resin is a weight average molecular weight (Mw) of standard polystyrene conversion measured by GPC (gel permeation chromatography).
Although there is no restriction | limiting in particular as a formation method of this undercoat layer, It is preferable to form by apply | coating the hydrophilic compound containing composition containing a hydrophilic compound on a positive hole transport layer, and drying.
The hydrophilic compound-containing composition is a hydrophilic compound containing a photosensitive composition (so-called negative photoresist) that is polymerized or cured after exposure and obtains insoluble or hardly soluble properties in the developer in the subsequent development process. It may be a compound-containing composition, or a photosensitive composition (so-called positive photoresist) containing a composition in which an exposed portion changes due to light exposure and acquires a readily soluble property in a developing solution in a subsequent development step. ) -Containing hydrophilic compound-containing composition. In particular, an inorganic negative photosensitive composition may be employed. One example is an aqueous peroxopolytungstic acid solution. Examples of the preparation method include those described in the following documents. Excimer laser exposure characteristics of inorganic resists based on peroxopolytungstic acids.Ishikawa, Akira; Okamoto, Hiroshi; Miyauchi, Katsuki; Kudo, Tetsuichi. Cent. Res. Lab., Hitachi, Ltd., Tokyo, Japan.Proceedings of SPIE-The International Society for Optical Engineering (1989), 1086 (Adv. Resist Technol. Process. 6), 180-5. When such an inorganic photosensitive composition is used, the area defined by the bank is a trace of the interfacial reaction. Cannot be detected and remains as good as the surface before the bank was formed.

When the undercoat layer has photosensitivity, the bank resist layer, which will be described in detail below, and its photosensitive type (negative type or positive type) are usually matched.
In the present invention, the hydrophilic compound is a compound that dissolves or swells in water. Specifically, a compound having a functional group such as a carboxy group, a hydroxyl group, a sulfonic acid (salt) group, a phosphonic acid (salt) group, an amino group, an amide group, or a quaternary ammonium base in the molecule is preferable. . In particular, the hydrophilic compound is preferably an organic compound, and is preferably a hydrophilic resin in order to ensure resistance. Here, the hydrophilic resin is a resin having the above functional group, and usually refers to a resin obtained by polymerizing or condensing a unit (monomer or polymer) containing the above functional group, and has a weight average molecular weight (Mw). ) Refers to a polymer material having about 1000 to 2,000,000.

  Examples of hydrophilic resins include polyvinyl alcohol, polysaccharides, polyvinyl pyrrolidone, polyethylene glycol, gelatin, glue, casein, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, hydroxyethyl starch, sucrose octaacetate, ammonium alginate, sodium alginate, polyvinyl Amine, polyallylamine, polystyrene sulfonic acid, polyacrylic acid, water-soluble polyamide, maleic anhydride copolymer, gum arabic, water-soluble soybean polysaccharide, white dextrin, pullulan, curdlan, chitosan, alginic acid, enzymatically degraded etherified dextrin In addition to the above, (co) polymer (co) polymerized using a hydrophilic monomer, and the like.

  Examples of hydrophilic monomers include (meth) acrylic acid or its alkali metal salts and amine salts, itaconic acid or its alkali metal salts and amine salts, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, N-monomethylol ( (Meth) acrylamide, N-dimethylol (meth) acrylamide, allylamine or its hydrohalide salt, 3-vinylpropionic acid or its alkali metal salt and amine salt, vinylsulfonic acid or its alkali metal salt and amine salt, vinylpyrrolidone, 2-sulfoethyl (meth) acrylate, polyoxyethylene glycol mono (meth) acrylate, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxypolyoxyethylene glycol mono (me ), Such as acrylate, a carboxyl group, a sulfo group, a phosphoric acid group, an amino group or a salt thereof, hydroxyl group and a monomer having a hydrophilic group selected from an amide group and an ether group.

Moreover, what was illustrated as said hydrophilic monomer as hydrophilic compounds other than hydrophilic resin is mentioned, It is also preferable that these are contained as a monomer in a hydrophilic compound containing composition.
Examples of the hydrophilic compound include vinylpyrrolidone (co) polymers, (meth) acrylic acid (co) polymers, polyvinyl alcohol and derivatives thereof, and celluloses such as hydroxyethylcellulose, carboxymethylcellulose, and methylcellulose. A hydrophilic resin such as is preferable.

The hydrophilic compound-containing composition used in the present invention may contain one kind of these hydrophilic compounds or may contain two or more kinds.
The hydrophilic compound is preferably contained in the total solid content of the hydrophilic compound-containing composition in an amount of preferably 10% by weight or more, more preferably 20% by weight or more and 100% by weight or less.
The hydrophilic compound-containing composition according to the present invention may contain other components as necessary in addition to the hydrophilic compound. Other components include, for example, photopolymerization initiators, thermal polymerization initiators, ethylenically unsaturated compounds and other reactive compounds, surfactants, fillers, substrate adhesion enhancers, development accelerators such as acids and alcohols, colors Examples thereof include materials, thermal polymerization inhibitors, plasticizers, storage stabilizers, and surface protective agents. In particular, by adding a photopolymerization initiator or an ethylenically unsaturated compound to the hydrophilic compound-containing composition, the composition is made photosensitive, and can be polymerized together with the resin layer at the time of exposure. It is useful to ensure sex.

  Examples of the photopolymerization initiator and ethylenically unsaturated compound used in this case include those exemplified as the photopolymerization initiator and ethylenically unsaturated compound contained in the photosensitive composition described below. . When the hydrophilic compound-containing composition contains a photopolymerization initiator, the content is usually 0.01% by weight or more, usually 10% by weight or less, preferably 5% by weight in the total solid content of the composition. % Or less. When the hydrophilic compound-containing composition contains an ethylenically unsaturated compound, the content thereof is usually 1% by weight or more, preferably 3% by weight or more, and usually 80% by weight or less, preferably in the total solid content of the composition. Is 50% by weight or less.

  The solvent contained in the hydrophilic compound-containing composition is not particularly limited as long as the solid content of the hydrophilic compound-containing composition can be dissolved or dispersed and enables uniform coating. Alternatively, it is preferable to use an alcohol solvent, and it is particularly preferable that water and / or the alcohol solvent is a main component of the solvent contained in the hydrophilic compound-containing composition.

Specific examples of the alcohol solvent used in the hydrophilic compound-containing composition include alkyl alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, and tert-butyl alcohol. , Glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, butylene glycol monomethyl ether, 3-methyl-3-methoxybutanol, 3-methyl- 3-ethoxybutanol, 3-methyl-3-n-propoxybutanol, 3-methyl-3-isopropoxybutanol, 3-methyl Such as ru-3-n-butoxysibutanol, 3-methyl-3-isobutoxysibutanol, 3-methyl-3-sec-butoxybutanol, 3-methyl-3-tert-butoxysibutanol, 3-methoxybutanol, etc. Examples include alkoxy alcohols.

  The solvent for the hydrophilic compound-containing composition may be a solvent other than water or an alcohol solvent, and may be dioxane, tetrahydrofuran, 1,2-diethoxyethane, 1,2-dimethoxyethane, 1,2- Ethers such as dibutoxyethane, ketones such as acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, esters such as 3-methoxybutyl acetate, butyl diglycol acetate, ethyl diglycol acetate, propylene glycol monomethyl ether acetate, etc. Is mentioned. These may be used alone or mixed with water or an alcohol solvent.

The solvent contained in the hydrophilic compound-containing composition may be only one selected from water, the above-described alcoholic solvent, and other solvents, or may be a mixed solvent of two or more.
The total solid concentration in the hydrophilic compound-containing composition is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, preferably 10% by weight or less, more preferably 5% by weight or less. is there.

  Examples of the method for forming the undercoat layer by forming the hydrophilic compound-containing composition on almost the entire surface of the hole transport layer include the wet deposition method described above. As a drying method after film formation, a method of drying using a hot plate, an IR oven, or a convection oven is preferable. The drying temperature is usually 40 ° C. or higher, preferably 50 ° C. or higher, usually 200 ° C. or lower, preferably 130 ° C. or lower. Further, the drying time is preferably 15 seconds or more, preferably 30 seconds or more, preferably 5 minutes or less, and preferably 3 minutes or less. Drying may be a vacuum drying method in which drying is performed in a vacuum chamber without increasing the temperature, or a combination of vacuum drying and heat drying may be used.

The thickness of the undercoat layer obtained after drying is not particularly limited, but is preferably 1/3 or less of the finished bank height including the undercoat layer, particularly preferably 1/4 or less, and 1 / It is preferably 200 or more, particularly preferably 1/50 or more.
The specific thickness of the undercoat layer is preferably 5 nm or more, more preferably 7 nm or more, particularly preferably 10 nm or more, preferably 4 μm or less, more preferably 1 μm or less, and particularly preferably 0.5 μm or less. If the film thickness of the undercoat layer is less than this lower limit, the effect of the undercoat layer is difficult to obtain, and if it exceeds the upper limit, the organic thin film is difficult to be uniformly formed in the region partitioned by the bank as described above. Further, when the undercoat layer is not photosensitive, it is difficult to hold the upper bank resist layer.

(Resin layer)
A bank is formed by forming a photosensitive composition on almost the entire surface of the hole transport layer or the undercoat layer, and exposing and developing the film. In the present invention, a portion of the bank formed by the photosensitive composition is referred to as a resin layer. That is, in the present invention, a layer formed by the photosensitive composition before exposure and development is referred to as a bank resist layer, and the bank resist layer is cured by exposure and development to form a bank. It is called a layer.

First, the photosensitive composition will be described. The photosensitive composition usually contains an ethylenically unsaturated compound, a photopolymerization initiator, and a solvent. Further, it preferably contains a binder resin, a crosslinking agent, a surface modifier, an ink repellent component, and the like. Moreover, a coloring agent, a coating property improving agent, an ultraviolet absorber, a polymerization inhibitor, an antioxidant, a silane coupling agent, an epoxy compound, other resins, and the like can be appropriately blended.

(Ethylenically unsaturated compounds)
In the present invention, the ethylenically unsaturated compound means a compound having at least one ethylenically unsaturated bond in the molecule. A compound having two or more ethylenically unsaturated bonds in the molecule is preferable from the viewpoints of polymerizability, crosslinkability, and the difference in developer solubility between exposed and unexposed areas. In particular, the ethylenically unsaturated bond is more preferably a (meth) acrylate compound derived from a (meth) acryloyloxy group.

The content of the ethylenically unsaturated compound in the photosensitive composition is usually 5% by weight or more, preferably 10% by weight or more, and usually 80% by weight or less, preferably 70% by weight or less based on the total solid content. If the lower limit is not reached, sufficient sensitivity may not be obtained during exposure, and if the upper limit is exceeded, a preferable bank shape may not be ensured.
In the photosensitive composition, the ethylenically unsaturated compound may be contained alone or in combination of two or more. When two or more types are included, the content ratio represents a total of two or more types.

Examples of compounds having one or more ethylenically unsaturated bonds in the molecule include unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid, isocrotonic acid, maleic acid, itaconic acid, citraconic acid, and alkyl esters thereof. , (Meth) acrylonitrile, (meth) acrylamide, styrene and the like.
Examples of the compound having two or more ethylenically unsaturated bonds in the molecule include esters of unsaturated carboxylic acids and polyhydroxy compounds, (meth) acryloyloxy group-containing phosphates, hydroxy (meth) acrylate compounds and poly Examples include urethane (meth) acrylates with isocyanate compounds, and epoxy (meth) acrylates of (meth) acrylic acid or hydroxy (meth) acrylate compounds and polyepoxy compounds.

  The ethylenically unsaturated compound is preferably an ester of an unsaturated carboxylic acid and a polyhydroxy compound, or a urethane (meth) acrylate of a hydroxy (meth) acrylate compound and a polyisocyanate compound, and an unsaturated carboxylic acid and a polyhydroxy compound. Esters are more preferable, and among them, esters of pentafunctional or higher unsaturated carboxylic acids such as pentaerythritol hexa (meth) acrylate and dipentaerythritol penta (meth) acrylate with polyhydroxy compounds are particularly preferable.

(Photopolymerization initiator)
A photoinitiator will not be specifically limited if it is a compound which polymerizes the ethylenically unsaturated bond of an ethylenically unsaturated compound with actinic light, A well-known photoinitiator can be used.
Here, the actinic rays are used separately from the actinic energy rays, but are physically included in the category of actinic energy rays. Specifically, it is an electromagnetic wave distributed mainly around ultraviolet rays.
The content ratio of the photopolymerization initiator in the photosensitive composition is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 0.5% by weight or more with respect to the total solid content. The amount is usually 30% by weight or less, preferably 20% by weight or less. If the lower limit is not reached, curability may be reduced, and if the upper limit is exceeded, adhesion to the substrate may be reduced.

The blending ratio of the photopolymerization initiator to the ethylenically unsaturated compound is usually 1/1 to 100/1, preferably 2 as the value of (ethylenically unsaturated compound) / (photopolymerization initiator) (weight ratio). / 1 to 50/1. If the blending ratio of the ethylenically unsaturated compound and the photopolymerization initiator deviates from this range, adhesion and curability may be lowered.
In the photosensitive composition, only one kind of photopolymerization initiator may be contained, or two or more kinds thereof may be contained. When two or more types are included, the content ratio represents a total of two or more types.

  Specific examples of the photopolymerization initiator include halomethylated triazine derivatives, halomethylated oxadiazole derivatives, hexaarylbiimidazole derivatives, benzoin alkyl ethers, anthraquinone derivatives, benzophenone derivatives, acetophenone derivatives, thioxanthone derivatives, benzoate derivatives, Examples include an acridine derivative, a phenazine derivative, an anthrone derivative, a titanocene derivative, and an oxime ester compound.

  Other photopolymerization initiators that can be used in the present invention include Fine Chemicals, March 1, 1991, Vol. 20, no. 4, p16-p26, JP-A-59-152396, JP-A-61-151197, JP-B-45-37377, JP-A-58-40302, JP-A-10-39503, etc. The thing described in is mentioned.

  For the purpose of improving sensitivity, the photopolymerization initiator may be used in combination with a hydrogen donating compound or a thermal polymerization initiator. In this case, the content ratio of the hydrogen donating compound and the thermal polymerization initiator in the photosensitive composition is considered as a part of the photopolymerization initiator. As a combined ratio of the photopolymerization initiator, the hydrogen donating compound, and the thermal polymerization initiator, the hydrogen donating compound or the thermal polymerization initiator is preferably 5 to 300% by weight with respect to the photopolymerization initiator.

  Examples of the hydrogen-donating compound include mercapto group-containing compounds, polyfunctional thiol compounds, ammonium or sodium salt derivatives such as phenylglycine and phenylalanine, and ester derivatives of phenylalanine. Examples of the thermal polymerization initiator include azo compounds, organic peroxides, and hydrogen peroxide.

(solvent)
Although there is no restriction | limiting in particular as a solvent, Water or an organic solvent is mentioned. A solvent can be used individually by 1 type or in mixture of 2 or more types.
Examples of organic solvents include glycol monoalkyl ethers, glycol dialkyl ethers, glycol alkyl ether acetates, glycol diacetates, alkyl acetates, ethers, ketones, mono- or polyhydric alcohols, and aliphatic hydrocarbons. , Alicyclic hydrocarbons, aromatic hydrocarbons, chain or cyclic esters, alkoxycarboxylic acids, halogenated hydrocarbons, ether ketones, nitriles and the like.

  Commercially available solvents corresponding to the above include mineral spirit, Barsol # 2, Apco # 18 Solvent, Apco thinner, Soal Solvent No. 1 and no. 2, Solvesso # 150, Shell TS28 Solvent, carbitol, ethyl carbitol, butyl carbitol, methyl cellosolve, ethyl cellosolve, ethyl cellosolve acetate, methyl cellosolve acetate, diglyme (all trade names) and the like.

The solvent is capable of dissolving or dispersing each component in the photosensitive composition, and is selected according to the method of use of the photosensitive composition. It is preferable to do. More preferably, it is 70 degreeC or more and 260 degrees C or less, for example, propylene glycol monomethyl ether, 3-methoxy-1-butanol, propylene glycol monomethyl ether acetate, 3-methoxy-1-butyl acetate, isopropanol etc. are preferable.

  The solvent should be used so that the ratio of the total solid content in the photosensitive composition solution is usually 10% by weight or more, preferably 15% by weight or more, usually 90% by weight or less, preferably 50% by weight or less. Is preferred. If the total solid concentration in the photosensitive composition is below this lower limit, a uniform coating film may not be obtained, and if it exceeds the upper limit, the required film thickness may not be controlled.

(Binder resin)
The binder resin is not particularly limited as long as it is a resin that can be developed with a developer, but an alkali developer is preferable as the developer, and thus an alkali-soluble resin is preferable.
Examples of alkali-soluble resins include acrylic resins, resins containing ethylenically unsaturated groups and carboxy groups, modified novolac resins, carboxy group-containing urethane resins, modified epoxy resins, modified novolac resins, cardo resins, and the like. Although preferably used, resins containing various ethylenically unsaturated groups and carboxy groups are particularly preferred.

The content of the binder resin is usually 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more, usually 70% by weight or less, preferably 60% by weight or less, more preferably based on the total solid content. Is 50% by weight or less. If the lower limit is not reached, it may be difficult to ensure the shape of the bank. If the upper limit is exceeded, the sensitivity and developability may be reduced.
In the photosensitive composition, only 1 type of binder resin may be contained, or 2 or more types may be contained. When two or more types are included, the content ratio represents a total of two or more types.

The weight average molecular weight (Mw) of the binder resin is preferably in the range of 1,000 to 100,000. When the weight average molecular weight is less than 1,000, it is difficult to obtain a uniform coating film, and when it exceeds 100,000, the developability tends to decrease.
Hereinafter, the acrylic resin, the resin containing an ethylenically unsaturated group and a carboxy group, and the modified novolak resin will be described.

[A] Acrylic acid resin
The acrylic resin preferably contains a component derived from a monomer having a carboxy group or a phenolic hydroxyl group in the side chain or main chain in order to ensure alkali solubility, and development in a highly alkaline solution is possible. Resins are preferred.

  For example, a (meth) acrylic acid-based (co) polymer or a (meth) acrylic acid-based resin having a carboxy group (in particular, a (co) polymer containing a (meth) acrylic acid ester) is preferable. These acrylic resins are advantageous in that copolymers having different performances can be obtained by combining with various monomers, and the production method is easy to control.

[B] Resin containing ethylenically unsaturated group and carboxy group
As the resin containing an ethylenically unsaturated group and a carboxy group, it is preferable to use one or more kinds of resins having at least one known ethylenically unsaturated group and carboxy group.
As such a resin, from the viewpoint of alkali developability and the like, a carboxy group-containing vinyl resin having an ethylenically unsaturated group in the side chain and an acid-modified epoxy (meth) acrylate are preferable.

Examples of the carboxy group-containing vinyl resin having an ethylenically unsaturated group in the side chain include a reaction product of a carboxy group-containing vinyl resin and an epoxy group-containing unsaturated compound, a compound having two or more unsaturated groups, and an unsaturated resin. Examples thereof include a copolymer with a saturated carboxylic acid and / or an unsaturated carboxylic acid ester, and an E-R-N-T resin. The E-R-N-T resin is the component (E):
It was obtained by copolymerizing 5 to 90 mol% of epoxy group-containing (meth) acrylate and 10 to 95 mol% of other radical polymerizable compound copolymerizable with (R) component: (E) component. Component (N): Unsaturated monobasic acid is added to 10 to 100 mol% of the epoxy group contained in the copolymer, and 10 to 100 mol% of the hydroxyl group produced when this (N) component is added. (T) component: a resin obtained by adding a polybasic acid anhydride.

  As an acid-modified epoxy (meth) acrylate, an α, β-unsaturated group-containing carboxylic acid adduct of an epoxy resin is added with a polyvalent carboxylic acid and / or an anhydride thereof, and contains an unsaturated group and a carboxy group. Epoxy resin

[C] Modified novolac resin
The modified novolak resin is obtained by reacting one or more of the novolak resins with one or more of the unsaturated group-containing epoxy compounds, and further adding a polybasic acid and / or an anhydride thereof to the hydroxyl group of the reaction product. It is a resin obtained by adding seeds or two or more kinds (however, a resole resin may be used in place of the novolak resin).

(Amino compound)
Amino compounds can be used as crosslinking agents. As a content rate of the crosslinking agent in a photosensitive composition, it is 40 weight% or less normally with respect to the total solid, Preferably it is 30 weight% or less. Moreover, it is 0.5 weight% or more normally, Preferably it is 1 weight% or more. If the upper limit is exceeded, the storage stability of the photosensitive composition may deteriorate. On the other hand, if the value is lower than the lower limit, a curing acceleration effect cannot be expected. Examples of the amino compound include an amino compound having at least two methylol groups as functional groups and alkoxymethyl groups obtained by subjecting the methylol group to alcohol condensation modification having 1 to 8 carbon atoms.

(Surface modifier, development improver)
As the surface modifier or development improver, for example, a known cationic, anionic, nonionic, fluorine-based or silicon-based surfactant can be used. Further, as the development improver, known ones such as organic carboxylic acids or anhydrides thereof can be used. Moreover, the content is 20 weight% or less normally with respect to the total solid of a photosensitive composition, Preferably it is 10 weight% or less.

(Ink repellent component)
In the present invention, the ink repellent component is a component having a property of repelling ink forming an organic thin film formed in a region partitioned by the bank, and the ink repellent component contains the ink repellent component. Is a contact angle of 20 ° or more, more preferably 30 ° or more, and particularly preferably 45 ° or more. The ink repellency component is not particularly limited as long as it has an effect of imparting ink repellency to the bank, and examples thereof include fluorine-containing compounds and silicon-containing compounds, but fluorine-containing compounds are preferred.

As the fluorine-containing compound, a compound containing a perfluoroalkyl group (perfluoroalkyl group-containing compound) is preferable. For example, JP-A-7-35916, JP-A-11-281815, and International Publication No. 2004-042474. In addition to the liquid repellent compounds disclosed in JP 2005-60515 A, JP 2005-315984 A, JP 2006-71086 A, etc., BYK-340 (manufactured by Big Chemie), Modiper F200, F600, F3035 (above, manufactured by NOF Corporation) Footgent M series, S series, F series, G series, D series, oligomer series (above, manufactured by Neos), Unidyne (produced by Daikin Industries), trifluoropropyltri Chlorosilane (manufactured by Shin-Etsu Silicone), Surf Commercially available and such emissions S-386 (manufactured by AGC Seimi Chemical Co., Ltd.), a resin obtained by copolymerizing perfluoro group-containing acrylic monomer as a component and the like can also be mentioned.
Furthermore, a compound containing a perfluoropolyether group capable of avoiding a perfluoroalkyl group having more than 6 carbon atoms, which is concerned about safety, is also effective.

In addition, as the fluorine-containing compound, a fluorinated epoxy resin, a fluorinated polyimide resin, a fluorinated polyamide resin, a fluorinated polyurethane resin, a fluorinated siloxane resin, and a modified resin thereof can be used.
In addition, a fluorine-containing compound having a crosslinkable group is preferable because it is less likely to flow out during development processing. As the fluorine-containing compound having a crosslinkable group, for example, Megafax RS-101, RS-102, RS-105, RS-401, RS-402, RS-501, RS-502 (above, manufactured by DIC), Examples include, but are not limited to, OPTOOL DAC (manufactured by Daikin Industries), perfluoro (meth) acrylate, perfluorodi (meth) acrylate, and the like.

The content ratio of the fluorine-containing compound in the photosensitive composition also varies depending on the fluorine content of the fluorine-containing compound. When the fluorine content (fluorine concentration of the fluorine-containing compound) is 10% by weight or more, The content ratio of the fluorine-containing compound with respect to the total solid content is preferably 0.001% by weight or more, more preferably 0.05% by weight or more, preferably 10% by weight or less, and more preferably 6% by weight or less. When the fluorine content is less than 10% by weight, the content ratio of the fluorine-containing compound is preferably 0.1% by weight or more, more preferably 1% by weight or more, more preferably 70% by weight or less based on the total solid content of the photosensitive composition. Is preferable, and 50 weight% or less is more preferable. If the lower limit is not reached, the liquid repellency of the bank may be insufficient and color mixing may occur, and if the upper limit is exceeded, it may be difficult to ensure developability.
In the photosensitive composition, only 1 type of fluorine-containing compounds may be contained, or 2 or more types may be contained. When two or more types are included, the content ratio represents a total of two or more types.

(Coloring agent)
As the colorant, known colorants such as pigments and dyes can be used. Further, for example, when a pigment is used, a known dispersant or dispersion aid may be used in combination so that the pigment can be stably present in the photosensitive composition without agglomeration. In particular, by coloring the bank black, there is an effect that a clear pixel can be obtained. As a black colorant, in addition to black dye, carbon black, titanium black, and the like, it is also effective to give a low reflectance by mixing an organic pigment and coloring it black.

The content of the colorant is usually 60% by weight or less, preferably 40% by weight or less, based on the total solid content of the photosensitive composition.
(Polymerization inhibitor, antioxidant)
In the photosensitive composition, from the viewpoint of improving stability, a polymerization inhibitor such as hydroquinone or methoxyphenol, or a hindered phenol-based oxidation such as 2,6-di-tert-butyl-4-cresol (BHT). It is preferable to contain an inhibitor. The content is usually in the range of 5 ppm to 1000 ppm, preferably 10 ppm to 600 ppm, based on the total solid content of the photosensitive composition. Below the lower limit, the stability tends to deteriorate. If the upper limit is exceeded, curing may be insufficient, for example, when curing with light and / or heat.

(Silane coupling agent)
It is also preferable to add a silane coupling agent to the photosensitive composition in order to improve adhesion to the substrate. Various types of silane coupling agents such as epoxy, methacrylic, amino and imidazole can be used. The content is usually 20% by weight or less, preferably 15% by weight or less, based on the total solid content of the photosensitive composition.

(Epoxy compound)
It is also preferable to add an epoxy compound to the photosensitive composition in order to improve curability and adhesion to the substrate.
As the epoxy compound, constituting a repeating unit of a so-called epoxy resin, a polyglycidyl ether compound obtained by reacting a polyhydroxy compound and epichlorohydrin, a polyglycidyl ester compound obtained by reacting a polycarboxylic acid compound and epichlorohydrin, and The content of the polyglycyepoxy compound obtained by reacting the polyamine compound and epichlorohydrin is usually 40% by weight or less, preferably 30% by weight or less, based on the total solid content of the photosensitive composition. If the upper limit is exceeded, the storage stability of the photosensitive composition may deteriorate.

(Application of photosensitive composition)
Examples of the coating method for applying the photosensitive composition as described above onto the undercoat layer to form the bank resist layer include the wet film forming method. Among these, the die coating method is preferable.
The coating amount of the photosensitive composition is, as a dry film thickness, the height of the bank including the undercoat layer is usually 0.5 μm or more, preferably 1 μm or more, more preferably 1 μm or more, usually 10 μm or less, preferably 9 μm or less. More preferably, the amount is such that the film thickness is 7 μm or less. At this time, it is important that the dry film thickness or the height of the finally formed bank is uniform over the entire area of the substrate. If this variation is large, uneven defects will occur in the substrate patterned with the organic thin film.

(Dry)
It is preferable to use a hot plate, an IR oven, or a convection oven for drying after applying the photosensitive composition on the undercoat layer.
The drying conditions can be appropriately selected according to the type of the solvent component of the photosensitive composition, the performance of the dryer to be used, and the like. Dry at a temperature below ℃. Further, the drying time is preferably 15 seconds or more, preferably 30 seconds or more, preferably 5 minutes or less, and preferably 3 minutes or less. If the drying temperature is too low or the drying time is short, sufficient drying cannot be performed and the sensitivity becomes unstable. If the drying temperature is too high or the drying time is too long, the productivity decreases, the substrate, etc. There is a problem of thermal deterioration of the layer, which is not preferable.
The drying may be a reduced pressure drying method in which the temperature is not raised and drying is performed in a reduced pressure chamber, or may be used in combination with heat drying.

{Bank formation process}
As described above, on the undercoat layer, a photosensitive composition containing an ink repellent component is applied over the entire surface and dried to form a bank resist layer, and then the bank pattern is exposed using an exposure mask, Further, the bank is formed by removing the non-image portion together with the undercoat layer by development processing.

(exposure)
In the exposure, a negative exposure mask (mask pattern) is superimposed on the bank resist layer formed by applying and drying the photosensitive composition, and through this exposure mask, photoactive rays such as ultraviolet rays or visible rays are irradiated. Irradiate with a light source. When exposure is performed using an exposure mask in this way, the exposure mask is placed close to the bank resist layer, or the exposure mask is placed at a position away from the bank resist layer, and exposure is performed through the exposure mask. A method of projecting light may be used. Further, a scanning exposure method using laser light without using an exposure mask may be used.

At this time, in order to prevent the deterioration of the sensitivity of the bank resist layer due to oxygen, exposure is performed in a deoxygenated atmosphere or after forming an oxygen blocking layer such as a polyvinyl alcohol layer on the bank resist layer as necessary. May be.
The light source used for said exposure is not specifically limited. As the light source, for example, a xenon lamp, a halogen lamp, a tungsten lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a medium pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a fluorescent lamp, a lamp light source, an argon ion laser, a YAG laser, Examples include laser light sources such as excimer laser, nitrogen laser, helium cadmium laser, blue-violet semiconductor laser, and near infrared semiconductor laser. An optical filter can also be used when used by irradiating light of a specific wavelength.

The optical filter may be of a type that can control the light transmittance at the exposure wavelength with a thin film, for example, and the material in that case is, for example, a Cr compound (Cr oxide, nitride, oxynitride, fluoride, etc.), Examples include MoSi, Si, W, and Al.
Energy of exposure generally, 1 mJ / cm ² or more, preferably 5 mJ / cm ² or more, more preferably 10 mJ / cm ² or more, usually 300 mJ / cm ² or less, preferably 200 mJ / cm ² or less, more preferably 150 mJ / cm ² or less. In the case of the proximity exposure method, the distance between the exposure target and the mask pattern is usually 10 μm or more, preferably 50 μm or more, more preferably 75 μm or more, and usually 500 μm or less, preferably 400 μm or less, more preferably 300 μm or less.

(developing)
An image pattern can be formed by developing after performing the exposure described above. The developer used for development is not limited, but an aqueous solution of an alkaline compound or an organic solvent is preferably used.
The developer may further contain a surfactant, buffer, complexing agent, dye or pigment.

  Alkaline compounds include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium silicate, potassium silicate, sodium metasilicate, sodium phosphate, potassium phosphate Inorganic alkaline compounds such as sodium hydrogen phosphate, potassium hydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium hydroxide, mono-di- or triethanolamine, mono-di- or trimethylamine Mono-di- or triethylamine, mono- or diisopropylamine, n-butylamine, mono-di- or triisopropanolamine, ethyleneimine, ethylenediimine, tetramethylammonium hydroxide (TMAH), co The organic alkaline compound such emissions and the like. These alkaline compounds may be a mixture of two or more.

In addition, when using the organic thin film patterning substrate of the present invention for an organic electroluminescent device, it is preferable to use an aqueous solution of an organic alkaline compound as a developing solution from the viewpoint of little adverse effect on device performance.
In this case, if the concentration of the organic alkaline compound in the aqueous organic alkali solution is excessively high, the bank may be damaged, and if it is excessively low, sufficient developability may not be ensured.

Examples of the organic solvent include ethyl alcohol, isopropyl alcohol, benzyl alcohol, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, propylene glycol, diacetone alcohol and the like. An organic solvent may be used individually by 1 type, may use 2 or more types together, and may be used as aqueous solution.
For example, it may be used as an aqueous solution containing 0.05 to 5% by weight of organic alkali such as TMAH and 0.1 to 20% by weight of alcohol such as ethyl alcohol.

  Examples of the surfactant include nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, monoglyceride alkyl esters; alkylbenzenesulfonic acid Anionic surfactants such as salts, alkylnaphthalene sulfonates, alkyl sulfates, alkyl sulfonates, sulfosuccinate salts; amphoteric surfactants such as alkylbetaines and amino acids.

There is no particular limitation on the development processing method, but it is usually 10 ° C. or higher, preferably 15 ° C. or higher, usually 50 ° C. or lower, preferably 45 ° C. or lower, at immersion development, spray development, brush development, ultrasonic development. Etc. are performed.
During development, the undercoat layer in the non-image area is removed together with the bank resist layer. Accordingly, the bank resist layer and the undercoat layer do not remain in the non-image portion, and the substrate or other layer under the undercoat layer is exposed in the non-image portion. Here, the non-image portion is a portion that is removed by exposure and development, and is a portion other than remaining as a bank. A layer obtained by forming a photosensitive composition before exposure is called a bank resist layer, and after exposure, it is called a resin layer.

  The undercoat layer exists at the interface between the resin layer and the substrate, and the undercoat layer and the resin layer form a completely integrated bank, but the undercoat layer maintains the film when the photosensitive composition is applied. Normally, it is observed that two layers are formed even after the bank is formed. The undercoat layer preferably contains a hydrophilic compound. The resin layer preferably contains an ink repellent component. In this case, the ink repellent component may be inside the resin layer, but is present on the surface in order to exhibit ink repellency. It is preferable.

(Additional exposure and thermosetting)
After development, if necessary, additional exposure may be performed by a method similar to the above exposure method, or thermosetting treatment may be performed.
The conditions for the additional exposure are the same as the above exposure conditions.
The temperature of the thermosetting treatment condition is usually 100 ° C. or higher, preferably 150 ° C. or higher, more preferably 200 ° C. or higher, usually 280 ° C. or lower, preferably 250 ° C. or lower, more preferably 240 ° C. or lower. 5 minutes or more, preferably 20 minutes or more, usually 60 minutes or less. In particular, for the expression of liquid repellency, it is preferable to carry out the thermosetting treatment at 200 to 240 ° C. for about 20 to 60 minutes.

(1) A method of peeling a surface of a charge transport layer in a region partitioned by a bank after forming a bank on the charge transport layer
The organic thin film patterning substrate of the present invention is manufactured by forming a bank and a region partitioned by the bank on the charge transport layer, and then peeling the surface of the charge transport layer in the region partitioned by the bank. (Hereinafter referred to as surface peeling method). This method is preferable from the viewpoint that uniform light emission can be obtained because the photosensitive composition remaining on the surface of the region partitioned by the bank can be removed.

The organic thin film patterning substrate obtained by this surface peeling method is usually a substrate of the type shown in FIG. 1 (a), and is a substrate in which the distance A is larger than the distance B.
Here, the surface peeling means removing part or all of the thickness from the surface of the charge transport layer toward the inside.
As a surface peeling method, a bank formed and dried substrate is placed at a predetermined position of a spin coater, and an amount of the whole surface of the substrate covered with an organic solvent is dropped onto the substrate. After standing for a predetermined time, the spin coater is rotated to shake off the organic solvent, and the rotation is continued and dried. By selecting an appropriate organic solvent, the charge transport layer in the vicinity of the surface of the charge transport layer in the region surrounded by the bank can be peeled without impairing the function of the bank portion. Of course, it is important that the organic solvent and the surface of the charge transport layer in the region surrounded by the bank come into contact with each other under a suitable atmosphere, temperature, and humidity for a predetermined time. Is not limited to the method described above.

Other methods include immersing the organic substrate together with the substrate for a predetermined time, drying and drying the substrate, spraying the organic solvent on the rotating substrate for a predetermined time while rotating the substrate, and continuing to rotate and drying as it is And a method of holding, pulling up and drying the whole substrate in a vapor of an organic solvent for a predetermined time.
The type of the solvent is not particularly limited as long as it is an organic solvent that can appropriately peel the charge transport layer. Preferably, aromatic compounds such as toluene, xylene, methicylene, cyclohexylbenzene; halogen-containing solvents such as 1,2-dichloroethane, chlorobenzene, o-dichlorobenzene; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl Aliphatic ethers such as ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethyl Ether solvents such as aromatic ethers such as anisole and 2,4-dimethylanisole; Aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; Phenyl acetate and propionate Cycloalkenyl, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, organic solvents such as ester solvents such as benzoic acid n- butyl. These may be used individually by 1 type and may use 2 or more types together by arbitrary ratios and combinations. Other solvents can also be used, such as trifluoromethoxyanisole, pentafluoromethoxybenzene, 3- (trifluoromethyl) anisole, ethyl (pentafluorobenzoate), N, N-dimethylformamide, N, N-dimethylacetamide It is also possible to use amides such as dimethyl sulfoxide.

  Further, the substrate formed with the bank is installed in a pulse ionization apparatus including a pulse ionization means for intermittent ionization and an extraction electrode for extracting ions ionized by the pulse ionization means in a certain direction. The charge transport layer near the surface of the charge transport layer in the region surrounded by the bank is ionized by the pulse ionization means, and the ions generated by the extraction electrode are extracted, whereby the composition is separated from the substrate surface as ions. (For example, refer to JP-A-63-318057).

In addition, a fine ice particle-containing air stream in which finely generated ice particles with liquid nitrogen are ejected simultaneously with a compressed gas, or liquefied carbon dioxide is injected under atmospheric pressure or a reduced pressure environment on a substrate that has been formed in a bank and dried. The charge transport layer in the region surrounded by the bank of the substrate may be peeled off by exposure to a carbon dioxide gas flow containing fine dry ice particles obtained in (1). The diameter of a preferable ice grain or dry ice grain is 0.001 to 10 μm, more preferably 0.01 to 0.1 μm in terms of volume average diameter (D50). The gas is preferably air, or an inert gas such as nitrogen or argon, or a mixture thereof. More preferably, the compressed gas before mixing the ice particles, or before the dry ice particles are generated. The water content in the liquefied carbon dioxide is adjusted to a predetermined range. More preferably, it is 0.001 ppm or more and 1000 ppm or less. The ejection speed is determined by the gas discharge pressure and the nozzle shape, but an appropriate range can be found by adjusting the size of the substrate and the distance from the substrate.

The surface peeling region is usually aimed at a region surrounded by the formed bank, but depending on the peeling method, the bank surface is unavoidably included. Even in that case, since the bank has a sufficient thickness compared to the thickness of the removed charge transport layer, even if the thickness of the bank is reduced by an amount about the thickness of the removed charge transport layer. Its function is not inhibited.
The depth of peeling is aimed at the difference between the distance A and the optimum thickness of the charge transport layer, but before or after that, a step of forming the charge transport layer in the inner region where the bank is formed is arranged. If it is, it will not be caught by that value.
In addition, the charge transport layer may be completely peeled in that the photosensitive composition may remain on the entire surface of the region partitioned by the bank.
The state in which the charge transport layer is completely peeled is a state in which the lower layer of the charge transport layer in contact with the bank is exposed.
More specifically, when the charge transport layer is composed of one layer, the charge transport layer is formed on the electrode layer. That is, the electrode layer corresponds to the lower layer of the charge transport layer in contact with the bank. From this, when the charge transport layer is composed of one layer, the state where the charge transport layer is completely peeled means that the electrode layer is exposed.
In the case where the charge transport layer is composed of two or more layers, the first charge transport layer is disposed below the charge transport layer in contact with the bank (hereinafter referred to as “first charge transport layer”). And another charge transport layer (hereinafter referred to as “another charge transport layer”) or an electrode layer. Accordingly, when the charge transport layer is composed of two or more layers, the state where the charge transport layer is completely peeled refers to a state where other charge transport layers or electrode layers are exposed.
A general analysis method can be used as a method for confirming that the charge transport layer has been completely peeled off. For example, XPS, TOF-SIMS, AFM, etc. The method of confirming the made | formed area | region is mentioned.
In addition, the state in which the entire charge transport layer in contact with the bank is completely peeled means that the charge transport layer in contact with the bank can be seen when the partitioned region is observed or measured with the measurement instrument in the plan view. A state that is not detected or not detected.

There are various depth measurement methods, but in general, the probe method (atomic force microscope, tunneling electron microscope, etc.), stylus method (optical lever method), laser interferometry, optical interference phase difference detection A surface shape measuring method (product name: VertScan, manufactured by Ryoka System Co., Ltd.) or the like can be employed as a method for measuring the depth with high accuracy.
As a process after peeling, usually, it is conveyed to the next process without any processing, or a drying process is arranged.

The drying process is performed in various environments such as high pressure gas phase, air, reduced pressure gas phase, vacuum, and inert gas, and the temperature and time are appropriately set. In particular, it is more preferable to perform heat drying in an inert gas such as nitrogen.
Furthermore, a cleaning process may be arranged before the drying process. The cleaning step may be a cleaning method of rinsing in pure water, or a cleaning method using a liquid mixture with an organic solvent or water. In such cleaning in a liquid, a so-called microbubble cleaning method in which a gas is made into a very fine bubble (generally having a diameter of 10 μm or less) and passed through the liquid can be used. Alternatively, a so-called dry cleaning method may be used in which treatments such as ultraviolet light irradiation and plasma treatment are performed in an environment such as normal pressure and high pressure gas phase, dilute gas, or vacuum.

  After the peeling, a charge transport material may be formed on the region partitioned by the peeled bank by the following charge transport material film forming method (3). In this case, a substrate having the same distance A and distance B may be produced. However, as described above, such a substrate can remove the photosensitive composition remaining on the surface of the region partitioned by the bank. From the standpoint of obtaining uniform light emission. In this case, a substrate in which the distance B is larger than the distance A can be manufactured.

In particular, according to this method, since a new charge transport layer is formed immediately before forming the light emitting layer, a so-called “fresh” surface of the charge transport layer is formed in contact with the light emitting layer. This can provide an element structure that does not degrade element characteristics, particularly lifetime.

(3) A method of forming a charge transport material in a region partitioned by a bank after forming a bank on the charge transport layer
The organic thin film patterning substrate of the present invention can be manufactured by a method in which a bank and a region partitioned by the bank are formed on the charge transport layer, and then a charge transport material is formed on the region partitioned by the bank. (Hereinafter referred to as charge transport material film-forming method). This method is preferable from the standpoint that uniform light emission can be obtained because the photosensitive composition remaining on the surface of the region partitioned by the bank can be covered. In particular, when the method of depositing the charge transport material is a wet deposition method, the photosensitive composition remaining on the surface of the region partitioned by the bank is diluted by dissolving the solvent used in the wet deposition method. The effect can also be expected. The residue remaining on the surface in this manner is dispersed in the newly formed charge transport layer, thereby reducing the adverse effect of remaining on the surface and acting in the direction of improving the device characteristics.

The organic thin film patterning substrate obtained by this charge transport material film forming method is usually a substrate of the type shown in FIG. 1B, and is a substrate having a distance B larger than the distance A.
The charge transporting material formed here contains at least one kind of charge transporting compound, and even if it consists of one kind of compound, it consists of two or more kinds of compounds. Also good.

The charge transport material to be deposited is not particularly limited as long as it is a material having the same properties as the material of the charge transport layer constituting the surface of the region partitioned by the bank. In addition, charge transport is performed in the charge transport layer without any difference in ionization potential or electron affinity of the charge transport material, i.e., charge is transported in the charge transport layer without adding any particular electrical resistance. It is preferable that
In addition, the charge transport layer and the light emitting layer differ in that it is possible to select a material that forms a charge transport layer that relaxes the difference in ionization potential or electron affinity as much as possible when charges are transported. Is preferred.

Examples of the film forming method include (shadow mask) vapor deposition method and ink jet method.
The apparatus used for the vapor deposition method has a heating source capable of depositing an organic substance in a vacuum chamber and a holder capable of holding a substrate, which is a deposition target, on the upper portion of the superheat source, and a predetermined vacuum. It has a vacuum pump that can be pulled at any time.

  A substrate is set in a holder in a vacuum chamber, a deposit (each of single compounds constituting the composition for forming a charge transport layer) is set in a heating source, and the vacuum chamber is evacuated by a vacuum pump. When the predetermined degree of vacuum is reached, the deposited material set in the heating source is heated and deposited on the substrate while maintaining a predetermined deposition rate. At this time, a mask such as a metal mask that deposits only the inner area partitioned by the bank is placed on the front surface of the substrate (ie, between the heating source) and covered so as not to be deposited on the bank. Also good. When the deposited material reaches a predetermined film thickness, heating of the heating source is stopped, the vacuum is broken, and the substrate is taken out.

A so-called shadow mask method is used to cover areas where it is not desired to deposit, so that a so-called shadow mask is placed between the substrate and the heating source at the time of vapor deposition. Different charge transport layers may be formed.
In the ink jet method, a composition for forming a charge transport layer is dissolved in a suitable solvent (with the composition as a solute and maintaining a suitable solubility), and a coating liquid for forming a charge transport layer having a predetermined solid content concentration is obtained. In this method, the coating liquid is prepared in an ink jet apparatus after being adjusted, and ejected with an appropriate amount of droplets into each of the internal areas partitioned by the bank, and then the solvent is dried to form a film.

An ink jet apparatus is a micro droplet ejection apparatus having a micro ejection nozzle, and is usually an apparatus provided with a precise positioning and transport mechanism on a nozzle or a substrate to be ejected. There are various methods for discharging droplets. Generally, a voltage waveform discharge control nozzle having a piezoelectric element is used, and the discharge amount and discharge speed are set.
In general, the discharge volume is determined by the inner area surrounded by the bank and the height of the bank, the lyophilicity of the inner area surrounded by the bank, and the liquid repellency of the bank itself (contact angle to the solvent). Therefore, an appropriate amount is selected.

On the other hand, the discharge speed is optimized depending on the solvent used, and is selected so that the time from which the solute is not dried and deposited before the droplets are discharged and landed on the substrate is selected.
The film formation region is usually aimed at a region surrounded by the formed bank. However, depending on the film formation method, it is inevitable that the bank surface is partially included. Also in that case, it is preferable to adopt a method in which the deposited charge transport layer is not deposited on the top of the bank.

The target thickness of the film is the difference between the distance A and the optimum thickness of the charge transport layer, but before or after that, there is a step of peeling the charge transport layer in the inner region where the bank is formed. If it is, it will not be caught by that value.
There are various thickness measurement methods, but in general, the probe method (atomic force microscope, tunneling electron microscope, etc.), stylus method (optical lever method), laser interferometry, optical interference phase difference detection A surface shape measuring method (product name: VertScan, manufactured by Ryoka System Co., Ltd.) or the like can be employed as a method for measuring the thickness with high accuracy.

As the processing after the film formation, it is usually transferred to the next step without any processing, or a drying step is arranged. The drying process is performed in various environments such as high pressure gas phase, air, reduced pressure gas phase, vacuum, and inert gas, and the temperature and time are appropriately set. Especially, it is preferable to perform heat drying in an inert gas, for example, nitrogen.
Furthermore, a cleaning process may be arranged before the drying process. The cleaning step may be a cleaning method of rinsing in pure water, or a cleaning method using a liquid mixture with an organic solvent or water. In such cleaning in a liquid, a so-called microbubble cleaning method in which a gas is made into a very fine bubble (generally having a diameter of 10 μm or less) and passed through the liquid can be used. Alternatively, a so-called dry cleaning method may be used in which treatments such as ultraviolet light irradiation and plasma treatment are performed in an environment such as normal pressure and high pressure gas phase, dilute gas, or vacuum.

  After the film formation, the charge transporting material may be peeled off by the charge transporting material peeling method (1) in a region partitioned by the deposited bank. In this case, a substrate having the same distance A and distance B may be manufactured. However, as described above, such a substrate can remove both the photosensitive composition remaining on the surface of the region partitioned by the bank. Therefore, it is preferable from the viewpoint of obtaining uniform light emission. In this case, a substrate in which the distance B is smaller than the distance A can be manufactured.

<Organic electroluminescent device>
The present invention is an organic electroluminescent device using the organic thin film patterning substrate, wherein the organic thin film has one or more organic thin films in a region partitioned by the bank.
The organic thin film formed in the bank partition region may be one layer or two or more layers, but at least one layer is preferably a light emitting layer. The light emitting layer is preferably the lowermost layer, that is, the layer in contact with the charge transport layer in which the bank is formed.

The layer other than the light emitting layer may be a layer formed between the electrode layers of the organic electroluminescent element (that is, between the anode and the cathode).
In addition, the light emitting layer is usually formed by being partitioned for each color such as RGB in the bank partition region, but the other organic thin film is continuous with the bank and the bank partition region over the entire surface of the substrate. It may be formed.

(Formation of organic thin film)
The organic thin film patterning substrate of the present invention is used for forming an organic thin film in a region partitioned by banks on the substrate (hereinafter sometimes referred to as a bank partition region).
In order to form an organic thin film in the area partitioned by the bank on the substrate of the organic thin film patterning substrate, usually, an ink in which the components of the organic thin film are dissolved or dispersed in a solvent is supplied into the bank partitioned area and dried. (FIG. 2G).
A method for supplying the ink into the bank partition region is not particularly limited, but an ink discharge type coating method such as an ink jet method (droplet discharge method) or a nozzle print method (liquid flow discharge method) is preferable (Japanese Patent Laid-Open No. 59-1993). 75205, JP-A 61-245106, JP-A 63-235901), particularly the ink jet method is preferred.

As an ink solvent used in an ink ejection type coating method, it is generally known that a relatively high amount of a high boiling point solvent component is added to prevent the nozzle from being dried. It is preferable to select an optimum solvent in consideration of the above.
In particular, in the case of the ink jet method, when a droplet is deposited on the surface to be coated with a droplet size of 20 pl, a solvent having a droplet diameter of 100 to 400 μm after the lapse of 1 minute after the droplet deposition is preferable. More preferably, the droplet diameter is 150 to 300 μm. Thereby, it is possible to prevent the occurrence of film thickness unevenness and pinholes and to ensure the linearity of the end portion.

After the ink is supplied into the bank partition region, an organic thin film is formed by a drying process. For this drying condition, a known method can be freely selected, for example, a hot plate, an IR oven, a convection oven, etc. It is done. Moreover, you may combine the reduced pressure drying method of drying in a reduced pressure chamber, without raising temperature. The environment can be selected from the atmosphere, N ₂ gas, reduced pressure, etc. according to the characteristics of the organic thin film to be formed. In the method for producing an organic electroluminescent element of the present invention, an organic thin film patterning substrate is produced by the above-described method, and then a light emitting layer is formed directly or via another layer in a region partitioned by the bank. Also, it is preferably formed directly from the viewpoint of controlling the thickness of the light emitting layer.

(Light emitting layer)
The light emitting layer contains at least a material having a light emitting property (light emitting material) as a constituent material, and preferably a compound having a hole transporting property (hole transporting compound) or an electron transporting material. Contains a compound having properties (electron transporting compound). A light emitting material may be used as a dopant material, and a hole transporting compound, an electron transporting compound, or the like may be used as a host material. There is no particular limitation on the light-emitting material, and a material that emits light at a desired light emission wavelength and has favorable light emission efficiency may be used. Furthermore, the light emitting layer may contain other components as long as the effects of the present invention are not significantly impaired. In addition, when forming a light emitting layer with a wet film-forming method, it is preferable to use a low molecular weight material in any case.

(Luminescent material)
Any known material can be applied as the light emitting material. For example, a fluorescent material or a phosphorescent material may be used, but a phosphorescent material is preferable from the viewpoint of internal quantum efficiency. Alternatively, blue may be used in combination, such as using a fluorescent material, and green and red using a phosphorescent material.

For the purpose of improving the solubility in a solvent, it is preferable to reduce the symmetry and rigidity of the molecules of the luminescent material, or to introduce a lipophilic substituent such as an alkyl group.
Hereinafter, examples of the fluorescent light emitting material among the light emitting materials will be given, but the fluorescent dye is not limited to the following examples.
Examples of the fluorescent light emitting material (blue fluorescent dye) that emits blue light include naphthalene, perylene, pyrene, chrysene, anthracene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof.

Examples of the fluorescent light emitting material (green fluorescent dye) that gives green light emission include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Al (C ₉ H ₆ NO) ₃ .
Examples of the fluorescent light emitting material (yellow fluorescent dye) that gives yellow light include rubrene, perimidone derivatives, and the like.

Examples of the fluorescent light-emitting material (red fluorescent dye) that emits red light include, for example, DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) -based compounds, benzopyran derivatives, rhodamine derivatives, Examples thereof include benzothioxanthene derivatives and azabenzothioxanthene.
As the phosphorescent material, for example, a long-period type periodic table (hereinafter referred to as a long-period type periodic table when referred to as “periodic table” unless otherwise specified) is selected from the seventh to eleventh groups. And an organometallic complex containing a metal.

Preferred examples of the metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold.
As the ligand of the complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand and a pyridine, pyrazole, phenanthroline, or the like is connected is preferable. A pyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

  Specific examples of the phosphorescent material include tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, tris (2- Phenylpyridine) osmium, tris (2-phenylpyridine) rhenium, octaethyl platinum porphyrin, octaphenyl platinum porphyrin, octaethyl palladium porphyrin, octaphenyl palladium porphyrin, and the like.

  The molecular weight of the compound used as the light emitting material is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 10,000 or less, preferably 5000 or less, more preferably 4000 or less, still more preferably 3000 or less, and usually 100 or more, Preferably it is 200 or more, More preferably, it is 300 or more, More preferably, it is the range of 400 or more. If the molecular weight of the luminescent material is too small, the heat resistance will be significantly reduced, gas generation will be caused, the film quality will be reduced when the film is formed, or the morphology of the organic electroluminescent element will be changed due to migration, etc. Sometimes come. On the other hand, if the molecular weight of the luminescent material is too large, it tends to be difficult to purify the organic compound, or it may take time to dissolve in the solvent.

In addition, only 1 type may be used for the luminescent material mentioned above, and 2 or more types may be used together by arbitrary combinations and a ratio.
The ratio of the light emitting material in the light emitting layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.05% by weight or more and usually 35% by weight or less. If the amount of the light emitting material is too small, uneven light emission may occur. If the amount is too large, the light emission efficiency may be reduced. In addition, when using together 2 or more types of luminescent material, it is made for the total content of these to be contained in the said range.

(Hole transporting compound)
The light emitting layer may contain a hole transporting compound as a constituent material. Here, among the hole transporting compounds, examples of the low molecular weight hole transporting compound include various compounds exemplified as the hole transporting compound in the hole injection layer 3 described above, for example, Aromatic diamine represented by 4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl containing two or more tertiary amines and two or more condensed aromatic rings substituted with nitrogen atoms (Japanese Patent Laid-Open No. 5-234681), aromatic amine compounds having a starburst structure such as 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine (Journal of Luminescence, 1997, Vol. 72-74, pp. 985), an aromatic amine compound comprising a tetramer of triphenylamine (Chemical Communications) 1996, pp. 2175), spiro compounds such as 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene (Synthetic Metals, 1997, Vol. 91, pp. 191 209) and the like.

In the light emitting layer, only one type of hole transporting compound may be used, or two or more types may be used in any combination and ratio.
The ratio of the hole transporting compound in the light emitting layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1% by weight or more and usually 65% by weight or less. If the amount of the hole transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of hole transportable compounds, it is made for the total content of these to be contained in the said range.

(Electron transporting compound)
The light emitting layer may contain an electron transporting compound as a constituent material. Here, among the electron transporting compounds, examples of low molecular weight electron transporting compounds include 2,5-bis (1-naphthyl) -1,3,4-oxadiazole (BND), 2,5, -Bis (6 '-(2', 2 "-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), bathophenanthroline (BPhen), 2,9-dimethyl-4,7 -Diphenyl-1,10-phenanthroline (BCP, bathocuproin), 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 4 , 4′-bis (9-carbazole) -biphenyl (CBP), etc. In the light emitting layer, only one type of electron transporting compound may be used, or two or more types may be combined in any combination. And it may be used in combination in the ratio.

  The ratio of the electron transporting compound in the light emitting layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1% by weight or more and usually 65% by weight or less. If the amount of the electron transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of electron transport compounds, it is made for the total content of these to be contained in the said range.

As described above, the light emitting layer is formed in the bank partition region, and is particularly preferably formed by an ink jet method. In this case, the above material is dissolved in an appropriate solvent to prepare a composition for forming a light emitting layer, and a film is formed using the composition.
As the luminescent layer solvent to be contained in the luminescent layer forming composition for forming the luminescent layer by the wet film forming method according to the present invention, any solvent can be used as long as the luminescent layer can be formed.
Suitable examples of the solvent for the light emitting layer are the same as those described for the composition for forming a hole injection layer.

The ratio of the solvent for the light emitting layer to the composition for forming the light emitting layer for forming the light emitting layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.01% by weight or more, usually 70% by weight or less, It is. In addition, when mixing and using 2 or more types of solvents as a solvent for light emitting layers, it is made for the sum total of these solvents to satisfy | fill this range.
The solid content concentration of the light emitting material, hole transporting compound, electron transporting compound and the like in the composition for forming a light emitting layer is usually 0.01% by weight or more and usually 70% by weight or less. If this concentration is too large, film thickness unevenness may occur, and if it is too small, defects may occur in the film.

After wet-deposition of the composition for forming a light emitting layer, the resulting coating film is dried and the solvent is removed to form a light emitting layer. Specifically, it is the same as the method described in the formation of the hole injection layer. The method of the wet film forming method is not limited as long as the effect of the present invention is not significantly impaired, and any of the methods described above can be used.
The thickness of the light emitting layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 3 nm or more, preferably 5 nm or more, and usually 200 nm or less, preferably 100 nm or less. If the light emitting layer is too thin, defects may occur in the film, and if it is too thick, the driving voltage may increase.

(Other layers)
Hereinafter, the layer and cathode formed between the electrode layers of the organic electroluminescent element (that is, between the anode and the cathode) other than the hole injection layer, the hole transport layer, and the light emitting layer described above will be described. The layer formed between the electrode layers may be used as a charge transport layer in the organic thin film patterning substrate, or may be used as an organic thin film formed in the bank partition region.
Of course, the hole injection layer, the hole transport layer, and the light emitting layer may also be used as a charge transport layer in the organic thin film patterning substrate, or may be used as an organic thin film formed in the bank partition region. .

{Hole blocking layer}
A hole blocking layer may be provided between the light emitting layer and an electron injection layer described later. The hole blocking layer is a layer stacked on the light emitting layer so as to be in contact with the cathode side interface of the light emitting layer.
The hole blocking layer has a role of blocking holes moving from the anode from reaching the cathode and a role of efficiently transporting electrons injected from the cathode toward the light emitting layer.
The physical properties required for the material constituting the hole blocking layer include high electron mobility, low hole mobility, large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). It is expensive. Examples of the material for the hole blocking layer satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, distyrylbiphenyl derivatives, etc. Triazole derivatives such as styryl compounds (JP-A-11-242996), 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (JP-A-7 -41759), phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. That. Furthermore, compounds having at least one pyridine ring substituted at the 2,4,6-positions described in International Publication No. 2005-022962 are also preferable as the material for the hole blocking layer.

In addition, the material of a hole-blocking layer may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of a hole-blocking layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.
The thickness of the hole blocking layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

{Hole relaxation layer}
The hole relaxation layer is a layer formed adjacent to the cathode side of the light emitting layer, and is a layer that functions to relax the accumulation of holes at the interface between the light emitting layer and the hole relaxation layer. It also has a role of efficiently transporting electrons toward the light emitting layer. For the hole relaxation layer, an electron transport compound (hole relaxation material) having a hole transport unit is used.

{Electron transport layer}
You may provide an electron carrying layer between a light emitting layer and the below-mentioned electron injection layer.
The electron transport layer is provided for the purpose of further improving the light emission efficiency of the device, and can efficiently transport electrons injected from the cathode between the electrodes to which an electric field is applied in the direction of the light emitting layer. Is formed.

  The electron transporting compound used for the electron transporting layer is usually a compound that has high electron injection efficiency from the cathode or the electron injection layer and has high electron mobility and can efficiently transport the injected electrons. Is used. Examples of the compound satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives , Distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compounds ( JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide , N-type zinc sulfide, n-type zinc Such as emissions of zinc, and the like.

In addition, only 1 type may be used for the material of an electron carrying layer, and 2 or more types may be used together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of an electron carrying layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.
The thickness of the electron transport layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

{Electron injection layer}
The electron injection layer plays a role of efficiently injecting electrons injected from the cathode into the light emitting layer. In order to perform electron injection efficiently, the material for forming the electron injection layer is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the film thickness is preferably from 0.1 nm to 5 nm.

Furthermore, an organic electron transport compound represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium ( JP-A-10-270
171, JP-A No. 2002-1000047, JP-A No. 2002-1000048, etc.) is preferable because it makes it possible to improve electron injection / transport properties and achieve excellent film quality. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.

In addition, only 1 type may be used for the material of an electron injection layer, and 2 or more types may be used together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of an electron injection layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

{cathode}
The cathode plays a role of injecting electrons into the layer on the light emitting layer side.
As the material of the cathode, it is possible to use the material used for the anode described above, but in order to perform electron injection efficiently, a metal having a low work function is preferable, for example, tin, magnesium, indium, calcium, A suitable metal such as aluminum or silver or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In addition, only 1 type may be used for the material of a cathode, and 2 or more types may be used together by arbitrary combinations and a ratio.
The thickness of the cathode is usually the same as that of the anode.
Further, for the purpose of protecting the cathode made of a low work function metal, it is preferable to further stack a metal layer having a high work function and stable to the atmosphere because the stability of the device is increased. For this purpose, for example, metals such as aluminum, silver, copper, nickel, chromium, gold and platinum are used. In addition, these materials may be used only by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.
The organic electroluminescent element according to the present invention may have another configuration without departing from the gist thereof. For example, any layer other than the layers described above may be provided between the anode and the cathode as long as the performance is not impaired, and any layer may be omitted.

{Electron blocking layer}
Examples of the layer that may be included include an electron blocking layer.
The electron blocking layer is provided between the hole injecting layer or the hole transporting layer and the light emitting layer, and prevents electrons moving from the light emitting layer from reaching the hole injecting layer. The role of increasing the recombination probability of holes and electrons in the process, confining the generated excitons in the light emitting layer, and the role of efficiently transporting the holes injected from the hole injection layer 3 in the direction of the light emitting layer. is there. In particular, when a phosphorescent material or a blue light emitting material is used as the light emitting material, it is effective to provide an electron blocking layer.

The characteristics required for the electron blocking layer include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Furthermore, in the present invention, when the light emitting layer is formed as an organic layer according to the present invention by a wet film formation method, the electron blocking layer is also required to be compatible with the wet film formation. Examples of the material used for such an electron blocking layer include a copolymer of dioctylfluorene and triphenylamine typified by F8-TFB (International Publication No. 2004/084260).

In addition, the material of an electron blocking layer may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of an electron blocking layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.
Furthermore, an ultrathin film formed of, for example, lithium fluoride (LiF), magnesium fluoride (MgF2), lithium oxide (Li2O), cesium carbonate (II) (CsCO3) or the like at the interface between the cathode and the light emitting layer or the electron transport layer. Inserting an insulating film (0.1 to 5 nm) is also an effective method for improving the efficiency of the device (Applied Physics Letters, 1997, Vol. 70, pp. 152; JP-A-10-74586; IEEE Transactions on Electron Devices, 1997, Vol. 44, pp. 1245; SID 04 Digest, pp. 154, etc.).

Moreover, in the layer structure demonstrated above, it is also possible to laminate | stack components other than a board | substrate in reverse order.
Furthermore, it is also possible to constitute the organic electroluminescent element according to the present invention by laminating components other than the substrate between two substrates, at least one of which is transparent.
In addition, a structure in which a plurality of components (light emitting units) other than the substrate are stacked in a plurality of layers (a structure in which a plurality of light emitting units are stacked) may be employed. In that case, instead of the interface layer between the steps (between the light emitting units) (when the anode is ITO and the cathode is Al, these two layers), for example, a charge made of vanadium pentoxide (V ₂ O ₅ ) or the like. When a generation layer (Carrier Generation Layer: CGL) is provided, a barrier between steps is reduced, which is more preferable from the viewpoint of light emission efficiency and driving voltage.

Furthermore, the organic electroluminescent device according to the present invention may be configured as a single organic electroluminescent device, or may be applied to a configuration in which a plurality of organic electroluminescent devices are arranged in an array. You may apply to the structure by which the cathode is arrange | positioned at XY matrix form.
Each layer described above may contain components other than those described as materials unless the effects of the present invention are significantly impaired.

<Organic EL display device>
The organic EL display device of the present invention uses the above-described organic electroluminescent element of the present invention. There is no restriction | limiting in particular about the model and structure of the organic electroluminescent display apparatus of this invention, It can assemble in accordance with a conventional method using the organic electroluminescent element of this invention.
For example, the organic EL display device of the present invention can be obtained by the method described in “Organic EL display” (Ohm, published on Aug. 20, 2004, Shizushi Tokito, Chiba Adachi, Hideyuki Murata). Can be formed.

<Organic EL lighting>
The organic EL illumination of the present invention uses the above-described organic electroluminescent element of the present invention. There is no restriction | limiting in particular about the model and structure of the organic EL illumination of this invention, It can assemble in accordance with a conventional method using the organic electroluminescent element of this invention.

Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples unless it exceeds the gist.
Example 1
<Anode>
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate with a thickness of 120 nm (manufactured by Sanyo Vacuum Co., Ltd., sputtered film) is 2 mm wide using ordinary photolithography and hydrochloric acid etching. An anode was formed by patterning the stripes. The substrate on which the anode is formed is cleaned in the order of ultrasonic cleaning with an aqueous surfactant solution, water cleaning with ultrapure water, ultrasonic cleaning with ultrapure water, and water cleaning with ultrapure water, followed by drying with a nitrogen blow, and finally UV irradiation. Ozone cleaning was performed.

<Hole injection layer>
Next, a composition for forming a hole injection layer was prepared. 2% by weight of a polymer having a repeating structure of the following formula (IV) (weight average molecular weight 60000) and 0.4% by weight of an electron-accepting compound represented by the following formula (A1) are dissolved in ethyl benzoate as a solvent. A composition for forming a hole injection layer having a solid content concentration of 2.4% by weight was obtained.

  On the board | substrate in which the said anode was formed, it formed into a film with the spin coat method using the said composition for positive hole injection layer formation. Spin coating was performed in an air atmosphere at a temperature of 23 ° C. and a relative humidity of 50%, the spinner rotation speed was 1500 rpm, and the spinner time was 30 seconds. After the film formation, it was heated and dried on a hot plate at 80 ° C. for 1 minute, and then baked in an oven atmosphere at 230 ° C. for 1 hour to crosslink the polymer, thereby forming a 30 nm thick hole injection layer.

<Hole transport layer>
Next, a composition for forming a hole transport layer was prepared. A polymer having a repeating structure of the following formula (V) (weight average molecular weight 95000) 1.4% by weight was dissolved in cyclohexylbenzene as a solvent to obtain a composition for forming a hole transport layer. Cyclohexylbenzene was obtained by adding a molecular sieve to a commercial product and dehydrated. The composition for forming a hole transport layer was prepared in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm.

The substrate on which the hole injection layer was formed was placed in a nitrogen glove box, and a film was formed on the hole injection layer by the spin coating method using the composition for forming a hole transport layer. The spinner speed was 1500 rpm and the spinner time was 30 seconds. After film formation, the polymer was crosslinked by baking at 230 ° C. for 1 hour on a hot plate to form a hole transport layer having a thickness of 32 nm.
The distance from the anode surface to the hole transport layer surface was measured by VertScan (manufactured by Ryoka Systems Inc.) and found to be 62 nm (distance A).

Preparation of the composition for forming a hole transport layer, film formation by spin coating, and baking were all performed in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm without being exposed to the atmosphere.
<Bank>
First, a photosensitive composition for forming a bank was prepared.

(Photosensitive composition)
(Synthesis of alkali-soluble resin)
First, an alkali-soluble resin (XXI) used as a binder resin for a photosensitive composition was synthesized as follows.

145 parts by weight of propylene glycol monomethyl acetate was stirred while being purged with nitrogen, and the temperature was raised to 120 ° C. 20 parts by weight of styrene, 57 parts by weight of glycidyl methacrylate, and 82 parts by weight of a monoacrylate having a tricyclodecane skeleton (“FA-513M” manufactured by Hitachi Chemical Co., Ltd.) were added dropwise thereto, and the mixture was further stirred at 140 ° C. for 2 hours. . Next, the reaction vessel was purged with air, 0.7 parts by weight of trisdimethylaminomethylphenol and 0.12 parts by weight of hydroquinone were added to 27 parts by weight of acrylic acid, and the reaction was continued at 120 ° C. for 6 hours. Thereafter, 52 parts by weight of tetrahydrophthalic anhydride (THPA) and 0.7 parts by weight of triethylamine were added and reacted at 120 ° C. for 3.5 hours to obtain an alkali-soluble resin (XXI) represented by the following formula:
Got. The obtained alkali-soluble resin (XXI) had a weight average molecular weight of 8,000.

(Preparation of photosensitive composition)
Next, a photosensitive composition was prepared.
First, 48 parts by weight of the synthesized alkali-soluble resin (XXI) as a binder resin,
24 parts by weight of dipentaerythritol hexaacrylate (DPHA) (manufactured by Nippon Kayaku Co., Ltd.) having the structure of the following formula (XII) as the ethylenically unsaturated compound and the structure of the following formula (XIII) as the ethylenically unsaturated compound The deconal acrylate DA-314 (manufactured by Nagase ChemteX Corporation) having 24 parts by weight, the compound having the structure of the following formula (XX) as an ethylenically unsaturated compound, 5 parts by weight, and the photopolymerization initiator represented by the following formula (XIV ) 1.5 parts by weight of Irgacure 907 (manufactured by Ciba Specialty Chemicals Co., Ltd.) having the structure of: polyether-modified silicone surfactant BYK-330 (manufactured by BYK Chemie, 51% active ingredient, solvent methoxypropyl) as a surface modifier 0.2 parts by weight of acetate) and MegaFac RS-102 (Dainippon Ink Chemical Co., Ltd.) A photosensitive composition having an active ingredient of 40 wt%, 1.63 parts by weight of MIBK: cyclohexanone = 75: 25 as a solvent, and propylene glycol monomethyl ether acetate (PGMEA) as a solvent and a total solid content of 25% by weight. A product was prepared.

(Film formation of photosensitive composition)
Next, in the yellow room where ultraviolet light was cut, the prepared photosensitive composition was formed on the entire surface of the hole transport layer by spin coating. The spin coating was performed in an air atmosphere at a temperature of 23 ° C. and a relative humidity of 50%. As the spin condition, after rotating at 400 rpm for 2 seconds, it was continuously rotated at 650 rpm for 30 seconds. After film formation, it was dried by heating on a hot plate at 80 ° C. for 60 seconds.

(exposure)
Next, exposure was performed. As the exposure apparatus, an exposure apparatus UX-1000SM-ACS01 manufactured by USHIO was used. As the exposure mask, a mesh-chromium-plated mask made of quartz glass having an opening with a square of 70 μm on one side, a light-shielding portion width of 30 μm, and arranged at a pitch of 100 μm vertically and horizontally was used. The gap between the substrate and the exposure mask was 100 μm. The exposure condition was 900 mJ.

(developing)
Next, an aqueous solution in which 0.48 wt% of tetramethylammonium hydroxide (TMAH), 0.4 wt% of nonionic surfactant Emulgen A-60 (manufactured by Kao Corporation) and 2 wt% of ethanol are dissolved is used as a developing solution. Development processing was performed. Development was performed using an automatic developing machine manufactured by Takizawa Sangyo Co., Ltd. The development conditions are as follows: shower development at a liquid temperature of 23 ° C. and a liquid pressure of 0.1 MPa for 30 seconds, followed by shower water washing at a liquid temperature of 23 ° C. and a liquid pressure of 0.1 MPa for 30 seconds, followed by a liquid temperature of 23 ° C. An ethanol shower treatment was carried out at a pressure of 0.1 MPa for 5 seconds, and finally, shower water was washed for 30 seconds at a liquid temperature of 23 ° C. and a liquid pressure of 0.1 MPa. After washing with water, it was dried with a nitrogen blow.

(Bake)
Finally, the substrate was placed in a nitrogen glove box and baked at 230 ° C. for 30 minutes on a hot plate in the nitrogen glove box. The nitrogen glove box had an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm.
As a result, a square bank with an opening of 70 μm per side, a bank width of 30 μm, and a vertical and horizontal array at a pitch of 100 μm was formed. The bank height was 1.9 μm.

(Surface peeling)
Next, in the substrate on which the bank was formed, the surface of the hole transport layer was peeled by dissolving the surface of the hole transport layer in a region (bank opening) partitioned by the bank with a solvent.
The substrate on which the bank is formed is taken out into the atmosphere and set in a spinner. 1,3-dimethoxybenzene is dropped over the entire area where the bank is formed, and is allowed to stand for 2 minutes, and then spins to 1,3-dimethoxy. Shake off benzene. The spin conditions were that after rotating at 500 rpm for 2 seconds, continuously rotating at 1500 rpm for 10 seconds, and further rotating continuously at 3000 rpm for 10 seconds. Then, it was heat-dried on a hot plate at 80 ° C. for 60 seconds. Spinning was performed in an air atmosphere at a temperature of 23 ° C. and a relative humidity of 50%.

Finally, the substrate was placed in a nitrogen glove box and baked at 230 ° C. for 10 minutes on a hot plate in the nitrogen glove box. The nitrogen glove box had an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm.
At this time, the distance from the anode surface to the hole transport layer surface was measured by VertScan (manufactured by Ryoka System Co., Ltd.) and found to be 56 nm (distance B). The surface of the hole transport layer (region partitioned by the bank) decreased in thickness by 6 nm.

(Light emitting layer)
Next, a composition for forming a light emitting layer for forming a light emitting layer as an organic thin film in a region partitioned by the bank was prepared.
100 parts by weight of the compound represented by the following formula (VI) and the compound 1 represented by the following formula (VII)
0 part by weight was dissolved in cyclohexylbenzene as a solvent to obtain a solution having a total solid content concentration of 3.1% by weight. This solution was filtered through a 0.2 μm PTFE filter to obtain a light emitting layer forming composition. The composition for forming a light emitting layer was prepared in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm.

  A light emitting layer was formed on the substrate on which the bank was formed by spin coating using the composition for forming the light emitting layer. The spin coating was performed in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm, the spinner rotation speed was 1200 rpm, and the spinner time was 30 seconds. After film formation, it was pre-dried at 130 ° C. for 1 minute on a hot plate, and then an unnecessary part on the electrode was wiped off, and then dried by vacuum heating on a hot plate at 130 ° C. for 1 hour to form a 77 nm thick light emitting layer. Formed.

Then, this board | substrate was arrange | positioned without exposing to the atmosphere in the chamber of the vacuum evaporation system connected with the glove box. The degree of vacuum in the chamber was 1.0 × 10 ⁻⁵ Pa. A vapor deposition mask was disposed in a predetermined area on the substrate, and necessary vapor deposition materials were previously placed in separate molybdenum boats in the chamber.

(Hole relaxation layer)
First, a molybdenum boat containing a compound represented by the following formula (VIII) was heated by energization and deposited on the substrate on which the light emitting layer was formed, thereby forming a hole relaxation layer. The deposition conditions were such that the degree of vacuum during deposition was 1.0 × 10 ⁻⁵ Pa, the deposition rate was 1.0 Å / s, and the hole relaxation layer was formed with a thickness of 10 nm.

(Electron transport layer)
Next, a molybdenum boat containing a compound (Alq ₃ ) represented by the following formula (iv) was heated by current application and evaporated on the hole blocking layer to form an electron transport layer. The deposition conditions were such that the degree of vacuum during deposition was 1.0 × 10 ⁻⁵ Pa, the deposition rate was 1.0 Å / s, and the electron transport layer was formed with a thickness of 30 nm.

(Electron injection layer)
Next, the substrate was placed in another vacuum chamber without being exposed to the atmosphere, and a 2 mm wide stripe-shaped shadow mask was placed as a cathode deposition mask so as to be orthogonal to the ITO ITO stripe. The degree of vacuum in the chamber was 1 × 10 ⁻⁵ Pa. Lithium fluoride (L
The molybdenum boat containing iF) was energized and heated and deposited on the electron transport layer. The vapor deposition conditions were as follows: the degree of vacuum during vapor deposition was 1.0 × 10 ⁻⁵ Pa, the vapor deposition rate was 0.05 Å / s, and the film thickness was 0.5 nm.

(cathode)
Next, the molybdenum boat containing aluminum was heated by energization to deposit the cathode. The deposition conditions were such that the degree of vacuum during deposition was 3.0 × 10 ⁻⁵ Pa, the deposition rate was 5.0 Å / s, and a film thickness of 80 nm was formed.
(Sealing)
The substrate was transferred to a nitrogen-substituted glove box without being exposed to the atmosphere. In a glove box substituted with nitrogen, a hygroscopic sheet is attached to the concave portion of the sealing glass plate, and a UV curable resin coating is applied around the concave portion of the sealing glass plate with a dispenser. Were sealed so as to be sealed with a sealing glass plate, and UV light was irradiated with a UV lamp to cure the UV curable resin.
As described above, an organic electroluminescent element was obtained.

(Element evaluation confirmation)
When this element was energized, blue light emission was obtained, and it was confirmed by microscopic observation that light was emitted uniformly throughout the bank. Further, when this element was continuously energized at a current density of 50 mA / cm ^{2 and} the change in luminance was measured with a photodiode, the luminance after 3 hours was 89% of the initial luminance.

(Example 2)
When forming the bank, after baking, the substrate was not baked at 230 ° C. for 30 minutes, and the substrate was peeled off with 1,3-dimethoxybenzene, and then heated on a hot plate at 80 ° C. for 60 seconds. An organic electroluminescent element was produced in the same manner as in Example 1 except that after drying, baking was performed at 230 ° C. for 30 minutes on a hot plate in a nitrogen glove box.
When the distance from the anode surface to the hole transport layer surface before and after the peeling treatment of the hole transport layer surface was measured by VertScan (manufactured by Ryoka Systems Co., Ltd.), it was 61 nm before the peeling treatment of the hole transport layer surface ( The distance A) was 53 nm after the peeling treatment of the hole transport layer surface (distance B). The thickness of the hole transport layer (region partitioned by the bank) decreased by 8 nm.

(Element evaluation confirmation)
When this element was energized, blue light emission was obtained, and it was confirmed by microscopic observation that light was emitted uniformly throughout the bank. Further, when this element was continuously energized at a current density of 50 mA / cm ^{2 and} the change in luminance was measured with a photodiode, the luminance after 3 hours was 85% of the initial luminance.

(Comparative Example 1)
An organic electroluminescent element was produced in the same manner as in Example 1 except that the surface of the hole transport layer was not peeled off.
(Element evaluation confirmation)
When this element was energized, blue light emission was obtained, but it was confirmed by microscopic observation that light was emitted only in the vicinity of the bank and not in the entire bank opening region. This is presumed to be because the light-emitting layer ink could not be applied uniformly because a residue remained in the bank opening region.
Further, when this element was continuously energized at a current density of 50 mA / cm ^{2 and} the change in luminance was measured with a photodiode, the luminance after 3 hours was 75% of the initial luminance.

(Example 3)
The organic electroluminescent element was produced by changing the hole transport layer and the light emitting layer of Example 1 as follows.

(Formation of new surface)
After forming the bank as in Example 1, the formation of the surface of the hole transport layer was performed again, and the surface of the hole transport layer that was in contact with the bank was formed with a new hole transport layer (new hole transport layer). did.
As the hole transport material for forming the newly formed hole transport layer, a polymer having a repeating structure of the formula (V) was used in the same manner as that used for forming the hole transport layer.
An ink jet apparatus using an ink in which 1.0% of the hole transport layer material is dissolved in cyclohexylbenzene (CHB), and discharging is performed in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm. Was 5 m / sec, the discharge amount was 10 pl per drop, and the coating amount in one bank section was 5 drops. The application area was a pattern having 20 × 20 bank sections in a square area of 2 mm on a side. The opening of one bank section is a square with a side of 70 μm. Immediately after inkjet coating, the product was placed in a vacuum dryer and vacuum dried. The degree of vacuum during vacuum drying was 100 Pa or less. After drying, it was baked by heating at 230 ° C. for 1 hour on a hot plate to form a newly formed hole transport layer having a thickness of 2 nm.

  The distance from the anode surface to the hole transport layer surface before and after the new layer formation process on the hole transport layer surface was measured by VertScan (manufactured by Ryoka Systems Co., Ltd.). It was 50 nm (distance A), and 52 nm after the peeling treatment of the hole transport layer surface (distance B). The surface of the hole transport layer (region partitioned by the bank) increased in thickness by 2 nm.

(Light emitting layer)
Next, a light emitting layer forming composition for forming a light emitting layer as an organic thin film on the surface of the newly formed hole transport layer region partitioned by the bank was prepared.
50 parts by weight of a compound represented by the following formula (VIII), 50 parts by weight of a compound represented by the following formula (IX) and 5 parts by weight of a compound represented by the following formula (IX) were dissolved in cyclohexylbenzene as a solvent, A solution having a total solid concentration of 1.0% by weight was obtained. This solution was filtered through a 0.2 μm PTFE filter to obtain a light emitting layer forming composition. The composition for forming a light emitting layer was prepared in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm.

A light emitting layer was formed on the substrate on which the bank was formed by an inkjet method using the composition for forming a light emitting layer. In an ink jet apparatus, discharge is performed in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm. The discharge speed is 5 m / sec, the discharge amount is 10 pl per drop, and the application amount in one bank section is 5 Drops. The application area was a pattern having 20 × 20 bank sections in a square area of 2 mm on a side. The opening of one bank section is a square with a side of 70 μm. Immediately after inkjet coating, the product was placed in a vacuum dryer and vacuum dried. The degree of vacuum during vacuum drying was 100 Pa or less. After drying, it was pre-baked on a hot plate at 130 ° C. for 1 minute, and then heated and baked on a hot plate at 130 ° C. for 1 hour to form a light emitting layer having a thickness of 60 nm.
Other than this, an organic electroluminescent element was produced in the same manner as in Example 1.

(Element evaluation confirmation)
When this element was energized, green light emission was obtained, and it was confirmed by microscopic observation that light was emitted uniformly throughout the bank. When this element was continuously energized at a current density of 50 mA / cm 2 and the change in luminance was measured with a photodiode, the luminance after 3 hours was 95% of the initial luminance.

1. substrate
2. Charge transport layer (first)
2a. Charge transport layer
2b. Charge transport layer
3. Charge transport layer (second)
4). Subbing layer
5. Bank resist layer
6). Exposure mask
7). Actinic rays
8). Area partitioned by bank
9. Resin layer
10. Organic thin film
11. bank
12 Electrode layer
13. Distance A
14 Distance B

Claims (9)

For organic thin film patterning for an organic electroluminescent device having an anode layer, a hole injection layer, and a hole transport layer in this order on a substrate, and having a bank and a region partitioned by the bank on the hole transport layer A substrate,
In the region where the bank on the hole transport layer was formed from the interface between the anode layer and the hole injection layer, the hole transport layer was partitioned by the distance A from the bank interface and the bank on the hole transport layer. An organic thin film patterning substrate characterized by being smaller than the distance B to the surface of the region. A material constituting the hole transport layer at the interface between the hole transport layer and the bank in the region where the bank is formed;
The material constituting the hole transport layer on the surface of the region partitioned by the bank is composed of a material having the same repeating structure as the material used in the material constituting the hole transport layer and / or a different material. The organic thin film patterning substrate according to claim 1.   The organic thin film patterning substrate according to claim 1 or 2, wherein the material of the hole transport layer is a composition containing a crosslinkable arylamine derivative to which a crosslinkable group is bonded.   The substrate for organic thin film patterning according to any one of claims 1 to 3, wherein the bank contains an ink repellent component.   5. The organic thin film patterning substrate according to claim 1, wherein the bank has a laminated structure including an undercoat layer and a resin layer on the undercoat layer.   6. The organic thin film patterning substrate according to claim 5, wherein the undercoat layer contains a hydrophilic compound, and the resin layer contains an ink repellent component.   It is an organic electroluminescent element using the organic thin film patterning substrate according to any one of claims 1 to 6, and has an organic thin film including a light emitting layer in a region partitioned by the bank. An organic electroluminescent device.   An organic EL display device using the organic electroluminescent element according to claim 7.   Organic EL lighting using the organic electroluminescent element according to claim 7.

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