JP2008251270A - Organic electroluminescent element, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an organic EL element which carries out patterning of an organic EL layer by using a photolithography method, and which is superior in light-emitting characteristics and life characteristics. <P>SOLUTION: When carrying out the patterning of the organic EL layer by using the photolithography method, by installing a conductive protection layer between the organic EL layer and a photoresist layer, objectives are achieved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an organic electroluminescence element (hereinafter, electroluminescence may be abbreviated as EL) element using a photolithography method, and an electroluminescence element obtained thereby.

  In the EL element, holes and electrons injected from two opposing electrodes are combined in the light emitting layer, and the fluorescent material in the light emitting layer is excited by the energy to emit light of a color corresponding to the fluorescent material. Therefore, it has been attracting attention as a self-luminous planar display element. Among them, an organic EL element using an organic substance as a light emitting material has high luminous efficiency, such as being able to realize high luminance light emission even when an applied voltage is less than 10 V, and can emit light with a simple element structure. It is expected to be applied to advertisements that display these patterns in light emission and other simple display displays at low cost.

  In general, in manufacturing a display using an organic EL element, a light emitting layer and the like are patterned. As a patterning method of the light emitting layer, a method of evaporating a light emitting material through a shadow mask, a method of separately coating by an ink jet method, a photolithography method, and the like have been proposed.

  Among these methods, the photolithography method does not require a vacuum facility or the like having a highly accurate alignment mechanism as compared with the patterning method by vapor deposition, so that an organic EL element is manufactured relatively easily and inexpensively. be able to. In addition, the photolithography method is preferable in that it does not perform a pretreatment or the like on a structure or a substrate that assists patterning, as compared with a patterning method using an inkjet method. Furthermore, from the relationship with the ejection accuracy of the inkjet head, the photolithography method is more advantageous for the formation of a higher definition pattern.

  When patterning an organic EL layer by photolithography, when applying a photoresist on the organic EL layer, the organic material used for the organic EL layer is not only a photoresist solvent but also a photoresist developer, a peeling It is required to be insoluble in the liquid and the rinse liquid. However, since the organic material generally used for the organic EL layer is soluble in many solvents, it is difficult to form a photoresist layer by applying a photoresist on the organic EL layer.

  Therefore, for example, an anode, an organic EL layer, a cathode, and a protective layer are formed on the entire surface of the substrate, a photoresist layer is formed on the protective layer, this photoresist layer is patterned into a desired shape, and then reactive. A method of patterning an organic EL layer by successively etching the cathode, the protective layer, and the organic EL layer where the photoresist layer has been removed by ion etching (RIE) is disclosed (Patent Document 1 and Patent). Reference 2). In this method, it is not necessary to form a photoresist layer on the organic EL layer. However, in order to pattern the light emitting layer of three colors using this method, a cathode and a protective layer are vacuum-deposited on the organic EL layer, a photoresist layer is formed on the protective layer, and then the cathode and protective layer are formed. Since the steps of etching the layer and the organic EL layer and removing the photoresist layer are repeated, there is a problem that the process is very complicated and the manufacturing cost increases.

  Further, in Patent Document 2, in order to provide a cathode wiring, the cathode and the protective layer are again formed and patterned on the entire surface of the substrate on which the patterned organic EL layer, the cathode and the protective layer are provided. . In this method, the process is further complicated and the manufacturing cost is further increased. In addition, two protective layers are stacked on the organic EL layer, which leads to deterioration in performance such as light emission characteristics. There is.

  In addition, an organic EL layer is formed using a material obtained by mixing a light-emitting material, an organic material such as a hole or electron transport material, and a photosensitive resin, pattern exposure is performed, and an organic EL layer in an unexposed portion is formed. A method of patterning an organic EL layer by removing the film is disclosed (see Patent Document 3). In this method, it is not necessary to form a photoresist layer on the organic EL layer. However, particularly in the above-mentioned documents, it is necessary to mix a light-emitting material in a photosensitive resin, and the number of deactivation sites of light emission increases, and the characteristic deterioration is remarkable.

Further, an organic EL layer is formed using a material in which an organic material such as a light emitting material or a hole transporting material is mixed with a thermosetting resin, and the organic EL layer is cured by heat curing, and then the organic EL layer is cured. A method of patterning an organic EL layer by forming a photoresist layer on the layer is disclosed (see Patent Document 4). According to this method, a photoresist layer can be easily formed on the organic EL layer.
In Patent Document 4, after the first color light emitting layer is patterned by dry etching, the photoresist layer is peeled off once, and the first color light emitting layer is completely cured to expose the surface of the first color light emitting layer. In the state, the light emitting layer of the second color is formed. In this method, the surface of the light emitting layer of the first color is exposed to damage by dry etching for patterning the light emitting layer of the second color. Therefore, there is a problem that the light emission characteristics are deteriorated.

  Furthermore, the photoresist layer is formed on the organic EL layer by appropriately adjusting the solubility of the organic material used for the organic EL layer with respect to the photoresist solvent, the photoresist developer, the stripping solution, and the like. A method for patterning an EL layer has been proposed (see Patent Document 5). In this method, first, a photoresist layer is formed on the light emitting layer of the first color, patterned into a desired shape, and the light emitting layer of the first color in the portion where the photoresist layer has been removed is etched. Then, without removing the photoresist layer, a light emitting layer of the second color is formed, a photoresist layer is further formed on the light emitting layer of the second color, patterned into a desired shape, and the portion where the photoresist layer is removed The second color light emitting layer is etched. And after repeating such a process and patterning the light emitting layer of multiple colors, each photoresist layer is removed. According to this method, even when the second color light emitting layer is formed, the photoresist layer remains on the first color light emitting layer, and the first color light emitting layer is applied to form the second color light emitting layer. Since it is protected from dry etching for patterning the liquid and the light emitting layer of the second color, damage can be reduced. In this method, a photoresist is directly applied on the organic EL layer.

JP-A-9-293589 JP 2000-113982 A Japanese Patent Laid-Open No. 10-69981 JP 2001-237075 A JP 2004-6231 A

  However, when a photoresist is directly applied on the organic EL layer, the light emission characteristics, life characteristics, and the like may be deteriorated. This is because the photoresist component is slightly adhered to the surface of the organic EL layer even after the photoresist layer is peeled off, and it is thought that this small amount of the photoresist component has some influence on the light emission characteristics and life characteristics. .

  This invention is made | formed in view of the said problem, and is a manufacturing method of the organic EL element which patterns an organic EL layer using a photolithographic method, Comprising: Manufacturing of the organic EL element which is excellent in a light emission characteristic and a lifetime characteristic The main purpose is to provide a method. Furthermore, it aims at providing the organic EL element obtained by the manufacturing method of the organic EL element.

  As a result of diligent studies to solve the above problems, the present inventors pay attention to the residue of the photoresist component as a cause of deteriorating the light emission characteristics and life characteristics when the photoresist is directly applied on the organic EL layer. did. In general, a photoresist contains a resin as a main component, a photosensitive agent, and various additives for improving coating properties and the like. Further, the resin as the main component has been devised such as lowering the molecular weight in order to improve developability and peelability. When such a photoresist is applied directly on the organic EL layer, a slight amount of the photoresist component remains on the surface of the organic EL layer even after the photoresist layer is peeled off. May adversely affect life characteristics. Therefore, the present inventors can improve the light emission characteristics, life characteristics, etc. by providing a conductive protective layer between the organic EL layer and the photoresist layer so that the organic EL layer and the photoresist are not in direct contact with each other. The present invention was completed.

  That is, the present invention includes an organic EL layer forming step of forming an organic EL layer including at least a light emitting layer on a substrate on which a first electrode layer is formed, and an inorganic conductive material on the organic EL layer. Conductive protective layer forming step of forming a conductive protective layer, applying a photoresist on the conductive protective layer, forming a photoresist layer, forming a photoresist layer, pattern exposing the photoresist layer, and developing A photoresist layer patterning step of patterning the photoresist layer, and removing the conductive protective layer and the organic EL layer in a portion where the photoresist layer has been removed, whereby the conductive protective layer and the organic EL layer are removed. An organic EL layer patterning process for patterning, a peeling process for peeling the remaining photoresist layer, and the peeling process To provide a method of manufacturing the organic EL element characterized in that a second electrode layer forming step of forming a second electrode layer on the conductive protective layer exposed after.

  According to the present invention, the conductive protective layer is formed on the organic EL layer, and the photoresist layer is formed on the conductive protective layer. Further, only the photoresist layer formed on the conductive protective layer is peeled off. Therefore, the organic EL layer can be prevented from being exposed to the photoresist component. Further, since the second electrode layer is formed on the conductive protective layer without peeling off the conductive protective layer, for example, when the second electrode layer is formed by sputtering or the like, the second electrode layer is formed. The damage of the organic EL layer can be alleviated. Therefore, in the present invention, it is possible to produce an organic EL element having excellent light emission characteristics and a long lifetime.

  The present invention is also a method for manufacturing an organic EL element in which a light emitting layer of N colors (N is an integer of 2 or more) is formed in a pattern, wherein the first electrode layer is formed and includes at least the first color light emitting layer. The first color organic EL layer to the (N-1) th color organic EL layer including at least the (N-1) th color light-emitting layer are formed in a pattern, respectively, and the surface of each organic EL layer is inorganic. An organic EL layer forming step of forming an organic EL layer of the Nth color including at least the Nth color light emitting layer on a substrate on which a conductive protective layer containing a conductive material and a photoresist layer are laminated in this order; A conductive protective layer forming step of forming an N-th color conductive protective layer containing an inorganic conductive material on the N-color organic EL layer; and applying a photoresist on the N-th color conductive protective layer; Photo forming N color photoresist layer The Nth color photoresist layer is formed, and the Nth color photoresist layer remains in the Nth color light emitting region by pattern exposure and development of the Nth color photoresist layer. A photoresist layer patterning step of patterning the layer, and removing the N-th color conductive protective layer and the N-th color organic EL layer in a portion where the N-th color photoresist layer is removed. An organic EL layer patterning step for patterning the N-color conductive protective layer and the N-th color organic EL layer, a peeling step for peeling the remaining photoresist layers, and the conductive protective layers exposed after the peeling step The manufacturing method of the organic EL element characterized by having a 2nd electrode layer formation process which forms a 2nd electrode layer on it.

According to the present invention, since the Nth color conductive protective layer is formed on the Nth color organic EL layer, the photoresist is not directly applied on the Nth color organic EL layer. When patterning the organic EL layer of the Nth color, a conductive protective layer and a photoresist layer are arranged in this order on the surfaces of the patterned organic EL layers from the first color to the (N-1) th color, respectively. The N-th color organic EL layer and the N-th color conductive protective layer are further formed thereon, and a photoresist is applied on the N-th color conductive protective layer. The (N-1) color organic EL layer does not come into contact with the Nth color photoresist layer. Moreover, since only each photoresist layer formed on each conductive protective layer is peeled off, each organic EL layer can be prevented from being exposed to the photoresist component.
Furthermore, as described above, when patterning the organic EL layer of the Nth color, the conductive protective layer and the photo are formed on the surfaces of the patterned organic EL layers from the first color to the (N-1) th color, respectively. The resist layers are stacked in this order, and the Nth color organic EL layer and the Nth color conductive protective layer are further formed thereon, so that the Nth color organic EL layer is etched from the first color when the Nth color organic EL layer is etched. (N-1) The damage to the organic EL layer up to the color can be reduced.
In addition, since the second electrode layer is formed on each conductive protective layer after each photoresist layer is peeled off, for example, when the second electrode layer is formed by sputtering or the like, the second electrode layer is formed. The damage of the organic EL layer at the time can be reduced.
Therefore, in the present invention, it is possible to produce an organic EL element having excellent light emission characteristics and a long lifetime.

  In the above invention, the N-color light-emitting layer is preferably a three-color light-emitting layer. This is because, generally, light emitting layers of three colors of red, green, and blue are used for color display.

  Moreover, in this invention, it is preferable to form each said conductive protective layer by a vacuum evaporation method in each said conductive protective layer formation process. This is because, in the vacuum deposition method, the energy given to the organic EL layer is small because the kinetic energy of the gas substance is low.

  Furthermore, in the present invention, it is preferable that the second electrode layer is formed by a sputtering method in the second electrode layer forming step. Since the sputtering method has high film formation energy, a material having a high melting point such as In—Zn—O (IZO) or In—Sn—O (ITO) can be formed, and the film formation efficiency is further improved. It is.

  In the present invention, each organic EL layer forming step is a step of forming two or more organic layers including each light emitting layer, and a lower layer organic layer is applied by applying a lower layer forming coating solution. And an upper layer forming step of forming an upper organic layer by applying an upper layer forming coating liquid on the lower organic layer, and the lower organic layer is It is preferably insoluble in the solvent contained in the upper layer forming coating solution. This is because each organic layer can be laminated stably.

  At this time, the coating solution for forming the lower layer contains a curable binder, and the coating film obtained by applying the coating solution for forming the lower layer may be subjected to a curing process in the lower layer forming step. . This is because the organic material contained in the lower organic layer can be prevented from eluting when the upper organic layer is formed.

  Further, the lower layer forming coating solution contains a material whose solubility is changed by the action of thermal energy or radiation, and is obtained by applying the lower layer forming coating solution in the lower layer forming step. You may change the solubility of the said coating film by providing a coating film with thermal energy or irradiating a radiation. This is because, as in the case described above, this prevents the organic material contained in the lower organic layer from being eluted when the upper organic layer is formed.

  Furthermore, in this invention, it is preferable to remove each said conductive protective layer and each said organic EL layer of the part from which each said photoresist layer was removed by dry etching at each said organic EL layer patterning process. This is because in dry etching, color mixing or the like hardly occurs and a higher definition pattern can be formed.

  In addition, the present invention provides a substrate, a first electrode layer formed on the substrate, an organic EL layer formed in a pattern on the first electrode layer and including at least a light emitting layer, and the organic EL layer A conductive protective layer containing an inorganic conductive material and a second electrode layer formed on the conductive protective layer, the pattern shape of the organic EL layer, and the conductive layer Provided is an organic EL device characterized in that the protective layer has the same pattern shape.

According to the present invention, the conductive protective layer is formed on the organic EL layer, and the organic EL layer and the conductive protective layer have the same pattern shape. Therefore, when the organic EL element of the present invention is manufactured using a photolithography method. The organic EL element can be obtained by forming a photoresist layer on the laminated organic EL layer and the conductive protective layer and simultaneously patterning the organic EL layer and the conductive protective layer. In this case, since the photoresist layer is formed on the conductive protective layer, the organic EL layer can be prevented from being exposed to the photoresist component.
In addition, since the second electrode layer is formed on the conductive protective layer, for example, when the second electrode layer is formed by sputtering or the like, the impact on the organic EL layer at the time of forming the second electrode layer is reduced. Can be relaxed.
Therefore, in this invention, it can be set as the organic electroluminescent element which is excellent in the light emission characteristic and was long-lived.

  In the said invention, the said organic EL layer has two or more organic layers containing the said light emitting layer, and the lower organic layer contains the curable binder among the adjacent two organic layers. May be. This is because the organic material contained in the lower organic layer can be prevented from eluting when the upper organic layer is formed.

  In the above invention, the organic EL layer has two or more organic layers including the light emitting layer, and of the adjacent two organic layers, the lower organic layer has thermal energy or radiation. A material whose solubility is changed by the action of may be contained. This is because, as in the case described above, this prevents the organic material contained in the lower organic layer from being eluted when the upper organic layer is formed.

  In the present invention, by forming a conductive protective layer on the organic EL layer, the organic EL layer is prevented from being exposed to a photoresist component, and the organic EL layer is protected from impact during the formation of the second electrode layer. Thus, the light emission characteristic and the life characteristic can be improved.

  Hereinafter, the manufacturing method of the organic EL element and the organic EL element of the present invention will be described in detail.

A. First, the manufacturing method of the organic EL device of the present invention will be described.
The method for producing an organic EL device of the present invention includes a case where at least one light emitting layer is formed in a pattern and a case where an N color (N is an integer of 2 or more) light emitting layer is formed in a pattern. There are two aspects. Hereinafter, each aspect will be described.

I. 1st aspect The 1st aspect of the manufacturing method of the organic EL element of this invention is the organic EL layer formation process which forms the organic EL layer containing at least a light emitting layer on the board | substrate with which the 1st electrode layer was formed, and said organic A conductive protective layer forming step of forming a conductive protective layer containing an inorganic conductive material on the EL layer; a photoresist layer forming step of applying a photoresist on the conductive protective layer to form a photoresist layer; The photoresist layer is subjected to pattern exposure and development, whereby a photoresist layer patterning step for patterning the photoresist layer, and the conductive protective layer and the organic EL layer in a portion where the photoresist layer is removed are removed. An organic EL layer patterning step of patterning the conductive protective layer and the organic EL layer, and the remaining photoresist layer And a second electrode layer forming step of forming a second electrode layer on the conductive protective layer exposed after the peeling step.

The manufacturing method of the organic EL element of this aspect is demonstrated referring drawings.
FIG. 1 is a process diagram showing an example of a method for producing an organic EL element of this embodiment. First, the first electrode layer 2 is formed in a pattern on the substrate 1, the insulating layer 3 is formed between the patterns of the first electrode layer 2, and holes are injected onto the first electrode layer 2 and the insulating layer 3. The layer 4 and the light emitting layer 5 are formed to obtain the organic EL layer 6 (FIG. 1A, organic EL layer forming step). Next, the conductive protective layer 7 is formed on the light emitting layer 5 (FIG. 1B, conductive protective layer forming step).
Next, a positive photoresist is applied on the conductive protective layer 7 to form a photoresist layer 8 (FIG. 1C, a photoresist layer forming step). Next, the photoresist layer 8 is subjected to pattern exposure through a photomask 11 so that at least the photoresist layer 8 in the light emitting region 10 remains, and then developed with a photoresist developer and washed to obtain a patterned photo resist. A resist layer 8 ′ is formed (FIGS. 1D and 1E, a photoresist layer patterning step).
Next, by removing the portions of the conductive protective layer, the light emitting layer and the hole injection layer exposed by removing the photoresist layer, the patterned conductive protective layer 7 ', the light emitting layer 5' and the hole injection layer 4 'are removed. (FIG. 1F, organic EL layer patterning step).
Next, the photoresist layer 8 'positioned at the uppermost layer is peeled off (FIG. 1 (g), peeling step).
Finally, the second electrode layer 9 is formed on the conductive protective layer 7 '(FIG. 1 (h), second electrode layer forming step).

  In this aspect, since the conductive protective layer is formed on the organic EL layer to be patterned, a photoresist is not directly applied on the organic EL layer. In addition, after patterning the organic EL layer, only the photoresist layer formed on the conductive protective layer is peeled off, so that the photoresist layer can be peeled off so that the photoresist component does not contact the organic EL layer at all. . That is, the conductive protective layer can prevent the surface of the organic EL layer from being contaminated with a photoresist component, for example, a photosensitive agent, an additive, a resin, or the like. Accordingly, it is possible to avoid a decrease in the light emission characteristics and life characteristics of the organic EL layer due to the photoresist component.

  Further, in this embodiment, since the second electrode layer is formed on the conductive protective layer, when the second electrode layer is formed by sputtering or the like, the impact on the organic EL layer at the time of forming the second electrode Can be relaxed.

Conventionally, for example, when a second electrode layer is formed on an organic EL layer by a sputtering method, the organic EL layer is subjected to an impact caused by Ar ⁺ , a sputtered particle, an ionized electron, and the like with a high energy amount at several hundred volts. Therefore, the structure of the organic EL layer is changed, and in the injection of holes or electrons, non-radiative quenching is caused at the interface between the organic EL layer and the second electrode layer, and the light emission characteristics may be deteriorated. For example, when the second electrode layer is formed on the organic EL layer by sputtering, an electron injection layer containing an alkali metal or an alkaline earth metal is formed between the light emitting layer and the second electrode layer. In this case, since these metals are easily oxidized, the introduction of oxygen during the formation of the second electrode layer or the release of oxygen from the target may oxidize the metal and lose the electron injection function.

  In contrast, in this embodiment, since the second electrode layer is formed on the conductive protective layer, even when the second electrode layer is formed by a sputtering method, plasma gas ions during sputtering are sputtered. The impact on the organic EL layer due to particles, ionized electrons, and the like can be reduced. As a result, it is possible to suppress a decrease in the characteristics of the organic EL layer such as the element characteristics such as the light emission characteristics and the electron injection characteristics due to the impact when forming the second electrode layer.

  Therefore, in this embodiment, by forming a conductive protective layer on the organic EL layer, an organic EL element having excellent element characteristics such as light emission characteristics and lifetime characteristics, and organic EL layer characteristics such as electron injection characteristics is manufactured. It is possible.

Furthermore, since the conductive protective layer in this embodiment contains an inorganic conductive material and has a relatively low electrical resistance, an organic EL element exhibiting good current-voltage characteristics can be obtained.
Hereinafter, each process of the manufacturing method of the organic EL element of this aspect is demonstrated.

1. Organic EL Layer Forming Step The organic EL layer forming step in this embodiment is a step of forming an organic EL layer including at least a light emitting layer on the substrate on which the first electrode layer is formed.
Hereinafter, the organic EL layer, the first electrode layer, and the substrate will be described.

(1) Organic EL layer The organic EL layer in this embodiment is composed of one or more organic layers including at least a light emitting layer. That is, the organic EL layer is a layer including at least a light emitting layer, and the layer configuration is a layer having one or more organic layers. Usually, when an organic EL layer is formed by a wet method, it is difficult to stack a large number of layers in relation to the solvent, so that one or two organic layers are often formed. It is possible to further increase the number of layers by devising organic materials so as to have different solubility in water or by combining vacuum deposition methods.

  Examples of the organic layer constituting the organic EL layer other than the light emitting layer include a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer. This hole transport layer is often integrated with the hole injection layer by imparting a hole transport function to the hole injection layer. In addition, as an organic layer constituting the organic EL layer, holes or electrons such as a hole blocking layer and an electron blocking layer are prevented from penetrating, and further, exciton diffusion is prevented and excitons are placed in the light emitting layer. By confining, a layer for increasing the recombination efficiency can be cited.

  The structure of the organic EL layer may be a general structure, and only the light emitting layer, hole injection layer / light emitting layer, hole injection layer / light emitting layer / electron injection layer, hole injection layer / electron blocking layer / Examples thereof include a light emitting layer / electron injection layer, a hole injection layer / light emitting layer / electron transport layer, and the like.

  When laminating a plurality of organic layers including a light emitting layer, for example, after patterning the light emitting layer or the hole injection layer and the light emitting layer by a photolithography method, an electron transport layer or an electron injection is formed on the patterned light emitting layer. A layer or the like may be formed in a pattern by a vacuum deposition method. Further, for example, after the hole injection layer is formed in a pattern by a vacuum deposition method, a light emitting layer may be formed on the pattern hole injection layer and patterned by a photolithography method.

  When forming a hole injection layer and a light emitting layer as an organic EL layer, after forming the hole injection layer and the light emitting layer on the entire surface of the substrate, the hole injection layer and the light emitting layer are patterned by a photolithography method. Alternatively, only the light emitting layer may be patterned by a photolithography method. In particular, when the conductivity of the hole injection layer is high, the hole injection layer and the light emitting layer are preferably patterned by a photolithography method in order to maintain the diode characteristics of the device and prevent crosstalk. On the other hand, when the resistance of the hole injection layer is high, the hole injection layer may be patterned or not patterned.

Here, the solubility of the membrane is generally defined by the solubility when the solid components in the membrane are dissolved in a solvent (100 × weight of dissolved solid content / (weight of dissolved solid content + solvent amount)). . In such a definition, when the solubility is less than 0.1%, it is often determined that the solubility is insoluble or insoluble. However, even when a solvent that is determined to be hardly soluble or insoluble in the above definition is used, when the film is immersed in the solvent, the film dissolves and film loss occurs.
In particular, in the organic EL element, the film thickness of the organic EL layer is very thin, and generally the film thickness of one organic layer constituting the organic EL layer is 100 nm or less. For this reason, even when the film is immersed in a solvent whose solubility is 0.1% or less in the above definition and is hardly soluble or insoluble, the thickness is easily reduced if the film thickness is about 100 nm. End up.

Therefore, in the present invention, regarding the solubility of the film, a film is formed on the substrate and sufficiently dried, and the film is immersed in a solvent at 25 ° C. for 1 minute, and then the film thickness before and after the immersion is measured. Depending on the difference (film thickness before immersion-film thickness after immersion), it was defined as follows.
When the film loss is 1 nm or less / min ... Insoluble When the film loss is more than 1 nm / min to 20 nm or less / min ... Insoluble When the film loss is more than 20 nm / min to 100 nm or less / min ... Soluble Film reduction Is more than 100 nm / min .... Easily soluble In addition, the definition of the solubility of the film is applied not only to the organic EL layer but also to a conductive protective layer and a photoresist layer.

For example, as will be described later, when forming a conductive protective layer by applying a conductive protective layer-forming coating solution containing an inorganic conductive material on the organic EL layer, the organic layer constituting the organic EL layer Among them, the uppermost organic layer is preferably hardly soluble or insoluble in the solvent of the conductive protective layer forming coating solution, and particularly preferably insoluble.
Hereinafter, each structure of the organic EL layer will be described.

(I) Two organic layers In this embodiment, the organic EL layer has two or more organic layers including a light emitting layer, and the lower organic layer is applied by applying a lower layer forming coating solution. When forming an upper organic layer by applying an upper layer forming coating liquid on this lower organic layer, the lower organic layer is insoluble in the solvent contained in the upper layer forming coating liquid. Preferably there is. That is, the organic EL layer forming step is a step of forming two or more organic layers including a light emitting layer, and a lower layer forming step of applying a lower layer forming coating liquid to form a lower organic layer; An upper layer forming step of applying an upper layer forming coating solution on the lower organic layer and forming an upper organic layer, and the lower organic layer is used as a solvent contained in the upper layer forming coating solution. It is preferably insoluble. As a result, when the upper organic layer is formed, even if the solvent of the upper layer forming coating solution contacts the lower organic layer, the lower organic layer is not dissolved. It is because it can laminate.

  In order to make the lower organic layer insoluble in the solvent of the upper layer forming coating solution, a curable binder or a material whose solubility is changed by the action of heat energy or radiation is added to the lower organic layer. Alternatively, materials having different solubility may be used for the lower organic layer and the upper organic layer.

  Further, in order to make the lower organic layer insoluble in the solvent of the upper layer forming coating solution, the lower organic layer may contain a photoinitiator or the like. For example, a photoinitiator as described in Applied physics letter, Vol 81, (2002) can be cured by ultraviolet irradiation by mixing with the conductive polymer.

  Above all, in order to make the lower organic layer insoluble in the solvent of the upper layer forming coating solution, the lower organic layer is a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, etc. In this case, it is preferable to use a curable binder or a material whose solubility is changed by the action of thermal energy or radiation in the lower organic layer. That is, the lower layer forming coating liquid preferably contains a curable binder or a material whose solubility is changed by the action of thermal energy or radiation. When the lower organic layer is a light emitting layer, it is preferable to use a material whose solubility is changed by the action of thermal energy or radiation for the lower organic layer. That is, the lower layer forming coating liquid preferably contains a material whose solubility is changed by the action of thermal energy or radiation. If the lower organic layer is insoluble in the solvent of the upper layer forming coating solution, the organic material contained in the lower organic layer can be prevented from eluting when the upper organic layer is formed. It can suppress that the characteristic of a layer falls.

  Hereinafter, the case where the lower organic layer contains a curable binder and the case where a material whose solubility is changed by the action of thermal energy or radiation will be described separately.

(Curing binder)
The curable binder used in the lower organic layer is preferably one that is cured by the action of thermal energy or radiation, and examples thereof include a sol-gel reaction liquid, a photocurable resin, and a thermosetting resin. Note that the sol-gel reaction liquid refers to a reaction liquid that gels after curing.

  Especially, it is preferable that a sclerosing | hardenable binder contains organopolysiloxane. As this organopolysiloxane, for example, those described in JP-A 2000-249821 can be used.

  When the lower organic layer is a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, or the like, the lower organic layer includes the curable binder and a hole or electron injection material, Or it is preferable to contain a hole or electron transport material. Such a lower organic layer has good hole or electron injection efficiency and can be cured, and is good as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, etc. Because it works.

The lower layer forming coating solution is prepared by dispersing or dissolving the above curable binder and a hole or electron injecting material or a hole or electron transporting material in a solvent. For example, when the curable binder contains an organopolysiloxane, an alcohol such as ethanol or isopropanol is preferably used as the solvent.
Examples of the coating method for the lower layer forming coating liquid include spin coating, spray coating, dip coating, roll coating, and bead coating.

The lower organic layer can be formed by performing a curing treatment on a coating film obtained by applying a lower layer forming coating solution.
Examples of the curing treatment include application of thermal energy or irradiation with radiation.

(Material whose solubility is changed by the action of thermal energy or radiation)
Here, the change in the solubility of the material means that the polarity of the solvent in which the main component of the material is dissolved or dispersed is changed. When a layer containing a material whose solubility is changed by the action of thermal energy or radiation is changed by applying thermal energy or irradiating the material with radiation, the layer is used to form the layer. The solvent of the applied coating solution and the solvent in which the layer after application of heat energy or radiation is dissolved have different polarities.

  The degree to which the solubility of the material changes is such that the lower organic layer after application of heat energy or irradiation is not substantially dissolved or mixed in the solvent used in the lower layer forming coating solution. That's fine. Specifically, it suffices if the lower organic layer after application of thermal energy or irradiation is insoluble in the lower layer forming coating solution.

  Examples of the material whose solubility is changed by the action of thermal energy or radiation used for the lower organic layer are, for example, those in which a part or all of the hydrophilic group of the hydrophilic organic material is converted into a lipophilic group. In addition, those in which part or all of the lipophilic group returns to the hydrophilic group by the action of thermal energy or radiation are preferably used.

  In the above materials, it is not necessary that all the hydrophilic groups of the hydrophilic organic material are converted into lipophilic groups. The ratio at which the hydrophilic group is converted to the lipophilic group may be a level that can maintain solubility at a desired concentration or higher in a general non-aqueous organic solvent. Specifically, the hydrophilic organic material that dissolves or disperses in water or an alcohol-based solvent is dissolved to 0.5% by mass or more in a general non-aqueous solvent such as toluene, xylene, ethyl acetate, or cyclohexanone. The hydrophilic group is preferably converted to a lipophilic group.

  Further, in the above material, it is not necessary for all of the lipophilic groups to return to the hydrophilic groups. The ratio of the lipophilic group returning to the hydrophilic group may be such that the lower organic layer does not dissolve in the solvent of the upper layer forming coating solution. Specifically, the lipophilic group is hydrophilic to such an extent that a material that dissolves 0.5% by mass or more in toluene, xylene, ethyl acetate, cyclohexanone, etc. becomes insoluble or hardly soluble in toluene, xylene, ethyl acetate, cyclohexanone, etc. It is preferable to return to the sex group. At this time, it is not necessary to completely return to the original hydrophilic organic material.

  The hydrophilic organic material is not particularly limited as long as it has a hydrophilic group and can be dispersed or dissolved in water, and is appropriately selected according to the function required for the lower organic layer. For example, when a light emitting layer (upper organic layer) is formed on a hole injection layer (lower organic layer), as a hydrophilic organic material used for the hole injection layer, for example, JP-A-2006-318876 What is described can be mentioned.

  As a method of converting a hydrophilic group in a hydrophilic organic material into a lipophilic group, a part of or all of the lipophilic group returns to the hydrophilic group by the action of heat energy or radiation. Preferably there is. Here, the protective reaction refers to a reaction in which a hydrophilic group is derivatized and a protective group is temporarily introduced into the hydrophilic group. Examples of the protective reaction include those described in JP-A-2006-318876.

The coating solution for forming the lower layer can be prepared by dispersing or dissolving a material in which a part or all of the hydrophilic group of the hydrophilic organic material is converted into a lipophilic group in a solvent. At this time, a solvent that can disperse or dissolve a lipophilic material is used. As such a solvent, for example, those described in JP 2006-318876 A can be used.
In addition, the concentration of the material in which part or all of the hydrophilic groups of the hydrophilic organic material in the lower layer forming coating liquid are converted to lipophilic groups varies depending on the component or composition of the material, Usually, it is set at 0.1% by mass or more, preferably about 1% by mass to 5% by mass.

The lower organic layer can be obtained by applying thermal energy or irradiating a coating film obtained by applying the lower layer forming coating solution to change the solubility of the coating film. After the application of the lower layer forming coating solution, drying may be performed. Regarding the application of thermal energy and the irradiation of radiation, for example, the conditions described in JP-A-2006-318876 can be used.
Note that the mechanism by which the solubility of the material changes due to the action of thermal energy or radiation is described in detail in JP-A-2006-318876.

(Ii) Light emitting layer The light emitting material used for the light emitting layer in this embodiment is not particularly limited as long as it includes a material that emits fluorescence or phosphorescence and emits light. It may also serve as a transport function.

  For example, when forming a conductive protective layer by applying a conductive protective layer-forming coating solution on the light-emitting layer, the luminescent material is preferably insoluble in the solvent of the conductive protective layer-forming coating solution, Further, it is preferably insoluble in the photoresist stripping solution.

  Examples of the light-emitting material include a dye-based light-emitting material, a metal complex-based light-emitting material, and a polymer-based light-emitting material.

  Examples of dye-based luminescent materials include cyclopentamine derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazol derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, silole derivatives, thiophene ring compounds. Pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, pyrazoline dimers, and the like.

  Examples of the metal complex light emitting material include an aluminum quinolinol complex, a benzoquinolinol beryllium complex, a benzoxazole zinc complex, a benzothiazole zinc complex, an azomethyl zinc complex, a porphyrin zinc complex, a europium complex, or a central metal such as Al, Zn, Examples thereof include a metal complex having a rare earth metal such as Be or the like or Tb, Eu or Dy, and having a oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline structure or the like as a ligand.

  Examples of the polymer-based light emitting material include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and the like, or the above-described dye-based light emitting materials and metal complexes. Examples include those obtained by polymerizing a system light emitting material.

  As will be described later, in the case of forming a light emitting layer by applying a light emitting layer forming coating solution, from the viewpoint of taking advantage of the fact that the light emitting layer can be accurately patterned by a photolithography method, It is preferable to use the above polymeric light emitting material.

  Further, various additives can be added to the light emitting material. For example, a doping agent may be added to the light emitting material for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of such doping agents include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazoline derivatives, decacyclene, phenoxazone, quinoxaline derivatives, carbazole derivatives, fluorene derivatives. Can be mentioned.

  In this embodiment, at least one light emitting layer is formed in a pattern, and for example, in the case of a full-color display, the light emitting layer has three colors of red, green, and blue, red, green, blue, Four colors of yellow, four colors of red, green, blue, and white, five colors of red, green, blue, yellow, and cyan can be used. Further, in the case of an area color display, the color to be displayed can be freely combined with the color of the luminescent color.

  As a method for forming the light emitting layer, a method of applying a light emitting layer forming coating solution containing the above light emitting material or the like, or a vacuum deposition method or the like can be used. Among these, from the viewpoint of reducing manufacturing costs, a method of applying a light emitting layer forming coating solution is preferable.

  In this embodiment, when a hole injection layer to be described later is formed and a light emitting layer is formed by applying a light emitting layer forming coating solution on the hole injection layer, the light emitting layer is formed. In order to prevent the material forming the hole injection layer from being mixed or dissolved in the light emitting layer forming coating solution, and to maintain the original light emitting characteristics of the light emitting material, the light emitting layer forming coating solution is used. It is preferable to use a solvent that does not dissolve the hole injection layer.

  For example, when a material for forming a hole injection layer described later is dissolved in a polar solvent such as an aqueous solvent, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), or alcohol, examples of the solvent include, for example, JP-A-2006- No. 40741 can be used.

  Examples of the application method of the light emitting layer forming coating liquid include a dip coating method, a roll coating method, a blade coating method, a spin coating method, a micro gravure coating method, a gravure coating method, a bar coating method, and a wire bar coating method. , Casting method, flexographic printing method and the like.

  You may dry after application | coating of the said light emitting layer forming coating liquid.

  The light emitting layer in this embodiment does not contain a curing agent, and no curing / crosslinking treatment is performed when the light emitting layer is formed. For this reason, the light emitting layer remains soluble in the solvent of the light emitting layer forming coating solution.

  The thickness of the light emitting layer is not particularly limited as long as it can provide a function of emitting light by providing a recombination field between electrons and holes, and specifically 10 nm to 500 nm. Can be about.

(Iii) Hole Injecting Layer The hole injecting layer in this embodiment is provided between the anode and the light emitting layer so that holes can be easily injected into the light emitting layer.

  The material used for the hole injection layer is not particularly limited as long as it can stabilize the injection of holes into the light emitting layer. Examples of the hole-injecting material used for the hole-injecting layer include arylamines, phthalocyanines, vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide, titanium oxide and other oxides, amorphous carbon, polyaniline, polythiophene And conductive polymers such as polyphenylene vinylene and derivatives thereof. The conductive polymer may be doped with an acid. Specifically, bis (N- (1-naphthyl-N-phenyl) benzidine (α-NPD), 4,4,4-tris (3-methylphenylphenylamino) triphenylamine (MTDATA), poly (3 , 4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS).

In the case of forming a light emitting layer by applying a light emitting layer forming coating solution on the hole injecting layer, the material for forming the hole injecting layer is the same as the solvent of the light emitting layer forming coating solution. It is preferably insoluble.
In addition, about making a hole injection layer insoluble with respect to the solvent of the coating liquid for light emitting layer formation, since it described in the above-mentioned item of "(i) Two organic layers", explanation here Is omitted.

  As a method for forming the hole injection layer, a method of applying a coating solution for forming a hole injection layer containing the above hole injecting material or the like, a vacuum deposition method, or the like can be used. Among these, from the viewpoint of reducing manufacturing costs, a method of applying a hole injection layer forming coating solution is preferable.

  The solvent used in the coating solution for forming the hole injection layer is not particularly limited as long as the above-described hole injection material is dispersed or dissolved, and is described in, for example, JP-A-2006-40741. Can be used.

  In addition, about the coating method of the hole injection layer forming coating liquid, it can be made to be the same as that of the coating method of the light emitting layer forming coating liquid.

  In addition, the thickness of the hole injection layer is not particularly limited as long as the thickness of the hole injection layer is sufficiently exhibited. Specifically, the thickness of the hole injection layer can be about 0.5 nm to 1000 nm. It is preferable to be within a range of ˜500 nm.

(Iv) Electron Transport Layer The electron transport layer in this embodiment is provided between the cathode and the light emitting layer so that electrons can be easily transported to the light emitting layer.

The material used for the electron transport layer is not particularly limited as long as it is a material that can transport electrons injected from the cathode into the light emitting layer. Examples of the electron transporting material used in the electron transporting layer include oxadiazoles, triazoles, bathocuproin, phenanthrolines such as bathophenanthroline, and aluminum quinolinol complexes such as tris (8-quinolinolato) aluminum complex (Alq ₃ ). Etc.

  As a method for forming the electron transport layer, a method of applying an electron transport layer forming coating solution containing the above electron transport material or the like, or a vacuum deposition method or the like can be used. Usually, a vacuum deposition method is used.

  The thickness of the electron transport layer is not particularly limited as long as the thickness of the electron transport layer is sufficiently exerted.

(V) Electron Injection Layer The electron injection layer in this embodiment is provided between the cathode and the light emitting layer so that electrons can be easily injected into the light emitting layer.

  The material used for the electron injection layer is not particularly limited as long as it can stabilize the injection of electrons into the light emitting layer. For example, an alkali metal such as an aluminum lithium alloy, lithium, or cesium is used. Alkaline metal halides such as lithium fluoride and cesium fluoride; alkaline earth metals such as strontium and calcium; alkaline earth metals such as magnesium fluoride, strontium fluoride, calcium fluoride, and barium fluoride And oxides such as magnesium oxide, strontium oxide, and aluminum oxide. Examples of the material used for the electron injection layer include sodium polymethyl methacrylate polystyrene sulfonate.

  As a method for forming the electron injection layer, a method for applying a coating solution for forming an electron injection layer containing the above materials or the like, a vacuum deposition method, or the like can be used. Usually, a vacuum deposition method is used.

  The thickness of the electron injection layer is not particularly limited as long as the thickness of the electron injection layer is sufficiently exhibited.

(2) First electrode layer The first electrode layer used in this embodiment may be an anode or a cathode. In general, when an organic EL element is produced, it is preferable that the first electrode layer is an anode because the organic EL element can be stably produced by laminating from the anode side.

  For the anode, a conductive material having a large work function is preferably used so that holes can be easily injected. On the other hand, a conductive material having a small work function is preferably used for the cathode so that electrons can be easily injected. As the conductive material, a metal material is generally used, but an organic substance or an inorganic compound may be used. A plurality of materials may be mixed and used for the first electrode layer.

  The first electrode layer may or may not have transparency, and is appropriately selected depending on the light extraction surface. For example, when the bottom emission type is used in the organic EL element shown in FIG. 1 (h), the first electrode layer 2 preferably has transparency. On the other hand, for example, when the top emission type is used in the organic EL element shown in FIG. 1 (h), the first electrode layer 2 is not required to be transparent. For example, when light is extracted from both sides in the organic EL element shown in FIG. 1H, the first electrode layer 2 preferably has transparency.

  As a conductive material having transparency, In—Zn—O (IZO), In—Sn—O (ITO), Zn—O—Al, Zn—Sn—O, and the like can be exemplified as preferable examples. Further, when transparency is not required, a metal can be used as the conductive material, specifically, Au, Ta, W, Pt, Ni, Pd, Cr, or Al alloy, Ni alloy, Cr alloy. Etc.

  Whether the first electrode layer is an anode or a cathode, the resistance is preferably relatively small.

  As a method for forming the first electrode layer, a general electrode forming method can be used, and examples thereof include a sputtering method, an ion plating method, and a vacuum deposition method. An example of the patterning method for the first electrode layer is a photolithography method.

(3) Substrate The substrate used in this embodiment may or may not have transparency. For example, in the case of the bottom emission type in the organic EL element shown in FIG. 1 (h), the substrate 1 preferably has transparency. On the other hand, for example, when the top emission type is used in the organic EL element shown in FIG. For example, when light is extracted from both sides in the organic EL element shown in FIG. 1H, the substrate 1 preferably has transparency.
For the transparent substrate, for example, an inorganic material such as glass, a transparent resin, or the like can be used.

  The transparent resin is not particularly limited as long as it can be formed into a film shape, but preferably has high transparency, relatively high solvent resistance and heat resistance. Examples of such transparent resins include polyether sulfone, polyethylene terephthalate (PET), polycarbonate (PC), polyether ether ketone (PEEK), polyvinyl fluoride (PFV), polyacrylate (PA), and polypropylene (PP). , Polyethylene (PE), amorphous polyolefin, or fluorine-based resin.

2. Conductive protective layer forming step The conductive protective layer forming step in this embodiment is a step of forming a conductive protective layer on the organic EL layer.

  In this embodiment, since the photoresist layer is formed on the conductive protective layer, the conductive protective layer is preferably insoluble or hardly soluble in the photoresist solvent. On the other hand, when the conductive protective layer is soluble in the photoresist solvent, it is possible to prevent the photoresist component from reaching the surface of the organic EL layer by making the conductive protective layer relatively thick. In this case, a layer that is insoluble or hardly soluble in the photoresist solvent and does not contain the photoresist component may be formed on the conductive protective layer.

  The conductive protective layer is preferably insoluble or hardly soluble in the photoresist developer. This is because the photoresist layer can be stably patterned and a high-resolution display can be manufactured. On the other hand, even when the conductive protective layer is soluble in the photoresist developer, there is no particular problem because the area of the exposed portion of the conductive protective layer exposed to the photoresist developer is relatively small.

  Furthermore, the conductive protective layer is preferably insoluble or hardly soluble in the photoresist stripping solution.

  Moreover, the conductive protective layer may or may not have transparency, and is appropriately selected according to the light extraction surface. For example, when the top emission type is used in the organic EL element shown in FIG. 1 (h), the conductive protective layer 7 ′ preferably has transparency. On the other hand, for example, in the case of the bottom emission type in the organic EL element shown in FIG. 1 (h), the conductive protective layer 7 ′ does not require transparency. For example, when light is extracted from both sides in the organic EL element shown in FIG. 1H, the conductive protective layer 7 ′ preferably has transparency.

Specifically, when the conductive protective layer has transparency, the average transmittance in the visible light region (380 nm to 780 nm) is preferably 10% or more, and more preferably 40% or more. This is because when the average transmittance of the conductive protective layer is in the above range, an organic EL element suitable for a top emission type can be obtained.
In addition, let the said average transmittance | permeability be the value measured in room temperature and air | atmosphere using the ultraviolet visible spectrophotometer (Shimadzu Corporation UV-2200A).

  Furthermore, when the second electrode layer is formed by a sputtering method or the like in the second electrode layer forming step, which will be described later, in order to protect the organic EL layer from the impact at the time of forming the second electrode layer, conductive protection It is preferable that the layer has a function (impact mitigation function) for mitigating an impact at the time of forming the second electrode layer.

  The conductive protective layer is preferably formed by a film forming method that does not impact the organic EL layer. That is, the inorganic conductive material is preferably one that can be deposited by a deposition method that does not impact the organic EL layer.

  In this aspect, since the organic EL layer, the conductive protective layer, and the second electrode layer are laminated in this order, the work function of the inorganic conductive material is closest to the second electrode layer among the organic layers constituting the organic EL layer. It is preferable to take a value between the work function of the material forming the disposed organic layer and the work function of the material forming the second electrode layer.

  The inorganic conductive material used for such a conductive protective layer is appropriately selected according to the properties and functions required of the conductive protective layer. For example, as an inorganic conductive material used for a conductive protective layer having transparency, a film forming method that has transparency at a film thickness necessary for obtaining an impact relaxation function and does not give an impact to the organic EL layer It is preferable that the film can be formed by. Specific examples of such inorganic conductive materials include metals or alloys, metal oxides, metal halides, semiconductors, inorganic materials doped with metals, and materials mainly composed of carbon.

  The metal or alloy is particularly limited as long as it has transparency at a film thickness necessary for obtaining an impact relaxation function and can be formed by a film forming method that does not give an impact to the organic EL layer. is not. As such a metal or alloy, for example, Li, Mg, Ca, Ba, Al, Cu, Ag, Au, Cr, Fe, Ni, Pt, Pd, Zn, Sn, etc., or an alloy formed by a combination thereof can be used. It can be illustrated.

  The metal oxide is particularly limited as long as it has transparency at a film thickness necessary for obtaining an impact relaxation function and can be formed by a film forming method that does not give an impact to the organic EL layer. is not. Examples of such metal oxides include the above metal oxides.

  The metal halide is particularly limited as long as it has transparency at a film thickness necessary for obtaining an impact relaxation function and can be formed by a film forming method that does not give an impact to the organic EL layer. is not. Examples of such metal halides include the metal halides described above.

The semiconductor is not particularly limited as long as it has transparency at a film thickness necessary for obtaining an impact relaxation function and can be formed by a film forming method that does not give an impact to the organic EL layer. . Examples of such semiconductors include wide band gap semiconductors such as compounds composed of Group 2 and Group 6 elements of the periodic table, such as ZnSe, ZnS, ZnS _x Se _{1-x, and the} like. .

  As the inorganic material doped with metal, it is particularly preferable if it has transparency at a film thickness necessary for obtaining an impact relaxation function and can be formed by a film forming method that does not give an impact to the organic EL layer. It is not limited. Examples of the metal to be doped include Li, Cs, Ba, Sr, Ca, Be, Mg, Sc, Y, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, and Fe. , Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Ti, Sn, Pb, Bi, and the like. Examples of the inorganic material doped with these metals include oxides, nitrides, fluorides, sulfides, and mixtures of the above metals or semiconductors. In this case, the content (metal concentration) of the metal dopant in the conductive protective layer is preferably 30% or less in terms of volume ratio. It is because there exists a possibility that a conductive protective layer may become opaque when there is too much content of a metal dopant.

As a material mainly composed of carbon, a material having transparency at a film thickness necessary for obtaining an impact mitigating function and particularly capable of being formed by a film forming method that does not give an impact to the organic EL layer can be used. It is not limited. As the conductive protective layer made of such a carbon-based material, a diamond-like carbon film, an amorphous carbon film, a fullerene film, a carbon nanotube film, or the like can be used.
The diamond-like carbon film refers to an amorphous carbon film containing an SP ² bonding component and an SP ³ bonding component of carbon and a polymer component. The diamond-like carbon film has high hardness, is chemically inert, is transparent to visible light to infrared light, has high smoothness, and has a dense structure. Therefore, it is possible to prevent moisture and oxygen from entering from the outside. In particular, when the electron injection layer contains an alkali metal or alkaline earth metal, the alkali metal or alkaline earth metal is easily affected by oxygen, but the conductive protective layer made of a carbon-based material is chemically Since it is inactive, the electron injection layer can be effectively protected.

  Moreover, the material which has carbon as a main component may contain only carbon substantially, and may contain metals other than carbon. The metal that can be used in combination with carbon is not particularly limited, and is appropriately selected depending on the work function, transmittance, film forming method, and the like. For example, when the material containing carbon as a main component contains carbon and an alkali metal such as Li, Na, or K, or an alkaline earth metal such as Mg, Ca, or Sr, the carrier doping effect and electrical conductivity Can be improved.

Furthermore, when a conductive protective layer made of a material containing carbon as a main component is formed by chemical vapor deposition, carbon is used as the main component by controlling the blending ratio of the hydrocarbon-based gas used as the source gas. The work function of the material to be adjusted can be adjusted.
Note that Japanese Unexamined Patent Application Publication No. 2004-335206 can be referred to for a conductive protective layer made of a material containing carbon as a main component.

  In addition, even when the conductive protective layer does not require transparency, the above-described inorganic conductive material can be used.

  The conductive protective layer may be a single layer or may be a laminate of two or more layers.

  The thickness of the conductive protective layer depends on the properties and functions required for the conductive protective layer (transparency, conductivity, impact mitigation function, etc.), the type of inorganic conductive material, and the method of forming the conductive protective layer. Is set as appropriate.

  For example, when the conductive protective layer is insoluble or hardly soluble in the photoresist solvent, the thickness of the conductive protective layer is preferably 0.5 nm or more. On the other hand, when the conductive protective layer is soluble in a photoresist solvent, the thickness of the conductive protective layer is preferably 100 nm or more.

  Further, for example, when the conductive protective layer has transparency, the thickness of the conductive protective layer is preferably a thickness that exhibits an impact mitigating function, satisfies the above transmittance, and satisfies a predetermined conductivity. It is set as appropriate according to the type of the conductive material and the method for forming the conductive protective layer. Specifically, when the conductive protective layer is a layer made of a metal or an alloy, the thickness of the conductive protective layer is preferably in the range of 1 nm to 30 nm, and more preferably in the range of 5 nm to 20 nm. Further, when the conductive protective layer is a layer made of a semiconductor or a layer made of an inorganic material doped with a metal, the thickness of the conductive protective layer is preferably in the range of 0.5 nm to 1000 nm. Preferably it exists in the range of 50 nm-500 nm. On the other hand, when the conductive protective layer is not required to be transparent, the thickness of the conductive protective layer may be larger than the above range as long as the thickness satisfies the predetermined conductivity.

  The method for forming the conductive protective layer is preferably a method that does not impact the organic EL layer. Examples of such a film forming method include chemical vapor deposition (CVD), physical vapor deposition (PVD) such as vacuum deposition, sputtering, and ion plating. Of these, the CVD method and the vacuum deposition method are preferable. This is because, in the CVD method or the vacuum deposition method, the energy given to the organic EL layer is small because the kinetic energy of the gas substance is low.

  Moreover, as a film-forming method of a conductive protective layer, the method of apply | coating the coating liquid for conductive protective layer formation containing said inorganic conductive material can also be used. Furthermore, when the conductive protective layer is formed into a film shape, the conductive protective layer can be laminated or transferred onto the organic EL layer directly or via an adhesive.

In particular, a vacuum deposition method is suitable as a method for forming the conductive protective layer. This is because the vacuum deposition method not only has the above-described advantages but also does not introduce a reactive gas such as oxygen. For this reason, even when the electron injection layer contains a highly reactive metal such as an alkali metal or an alkaline earth metal, oxidation of the metal can be avoided.
Therefore, even when the CVD method, the sputtering method, or the ion plating method is used, it is preferable to introduce a non-reactive gas such as a rare gas without introducing a reactive gas such as oxygen.

  Examples of the vacuum deposition method include a resistance heating deposition method, a flash deposition method, an arc deposition method, a laser deposition method, a high frequency heating deposition method, and an electron beam deposition method.

  Moreover, when apply | coating the coating liquid for conductive protective layer formation on an organic EL layer, and forming a conductive protective layer, the solvent used for this coating liquid for conductive protective layer formation is the organic layer which comprises an organic EL layer. Among them, it is preferable that the uppermost organic layer is not dissolved. For example, when a hole injection layer and a light emitting layer are formed as the organic EL layer, and the conductive protective layer is formed on the light emitting layer, the solvent is preferably one that does not dissolve the light emitting layer. In this case, the solvent may dissolve the hole injection layer or may not dissolve it.

  Such a solvent is not particularly limited as long as it can dissolve or disperse the above-described inorganic conductive material and satisfies the above-mentioned properties. Examples thereof include alcohols, ketones, ethers, esters, and the like. Can do. These solvents may be used alone or in combination of two or more.

  Further, even when the conductive protective layer forming coating solution contains a solvent that dissolves the uppermost organic layer, the uppermost organic layer may be insoluble or insoluble in the solvent.

  As a coating method of the conductive protective layer forming coating solution, for example, dip coating method, roll coating method, blade coating method, spin coating method, micro gravure coating method, gravure coating method, bar coating method, wire bar coating method, Examples thereof include a casting method and a flexographic printing method.

3. Photoresist Layer Forming Step The photoresist layer forming step in this embodiment is a step of forming a photoresist layer by applying a photoresist on the conductive protective layer.

  The photoresist used in this embodiment may be either a positive type or a negative type. Among these, considering the ease of peeling off the photoresist, a positive photoresist is preferable. As a photoresist, a general thing can be used, For example, a novolak-type resin, rubber | gum + bis azide-type resin etc. can be mentioned.

  In addition, as a photoresist solvent used for the photoresist, an inorganic conductive material or the like is used to prevent the conductive protective layer from being mixed or dissolved in the photoresist when the photoresist is applied on the conductive protective layer. It is preferable that it does not dissolve. As such a photoresist solvent, for example, those described in JP-A-2006-318876 can be used.

  The method for applying the photoresist is not particularly limited as long as it can be applied to the entire surface of the substrate. For example, the spin coating method, the casting method, the dip coating method, the bar coating method, and the blade coating method. Roll coating method, gravure coating method, spray coating method, flexographic printing method and the like are used.

  The film thickness of the photoresist layer is not particularly limited, but is 0.1 μm to 10 μm when the conductive protective layer and the organic EL layer are dry-etched in the organic EL layer patterning step described later. Preferably, it is in the range of 0.5 μm to 5 μm. This is because if the thickness of the photoresist layer is in the above range, dry etching with high processing accuracy can be performed while maintaining the resist function.

4). Photoresist Layer Patterning Step The photoresist layer patterning step in this embodiment is a step of patterning the photoresist layer so that the photoresist layer in the light emitting region remains by pattern exposure and development of the photoresist layer.

  As a method for pattern exposure of the photoresist layer, for example, a general method such as a method of exposing through a photomask or a laser drawing method can be used.

  At the time of pattern exposure, when a positive photoresist is used, exposure is performed so that at least the light emitting region is a non-exposed region, and when a negative photoresist is used, at least the light emitting region is an exposed region. To expose.

  The photoresist developer used in this embodiment is not particularly limited as long as it does not dissolve the inorganic conductive material or the like. As such a photoresist developer, a generally used organic alkaline developer can be used. Further, as the photoresist developer, an inorganic alkaline developer or an aqueous solution capable of developing the first color photoresist layer can also be used.

  Moreover, it is preferable to wash with water after developing the photoresist layer.

5. Organic EL layer patterning step The organic EL layer patterning step in this embodiment is a step of patterning the conductive protective layer and the organic EL layer by removing the portion of the conductive protective layer and the organic EL layer from which the photoresist layer has been removed. .

  As a method for removing the conductive protective layer and the organic EL layer, both wet etching using a solvent that dissolves the conductive protective layer and the organic EL layer, and dry etching can be used. Among these, dry etching is preferable because color mixing or the like hardly occurs and high-definition patterning is possible.

  In the wet etching, the conductive protective layer and the organic EL layer of the portion from which the photoresist layer has been removed are dissolved using a solvent that can dissolve the conductive protective layer and the organic EL layer without dissolving the photoresist layer. To remove. Examples of the solvent that can be used in this case include the solvents used in the above-described light emitting layer forming coating solution, hole injection layer forming coating solution, and conductive protective layer forming coating solution.

  In wet etching, the conductive protective layer and the organic EL layer may be removed in an ultrasonic bath. By using an ultrasonic bath, for example, it is possible to prevent the line width of the light emitting layer pattern from being narrowed or to prevent the light emitting material or the like from flowing out of the light emitting layer, thereby enabling highly accurate patterning. . Further, it is also preferable in that high-precision patterning can be performed in a short time.

  The ultrasonic conditions used for this ultrasonic bath are preferably at an oscillation frequency of 25 ° C. and 20 to 100 KHz, and 0.1 to 60 seconds. This is because such a condition enables high-precision patterning in a short time.

  In dry etching, the thickness of the photoresist layer is considerably thicker than that of the conductive protective layer and the organic EL layer. Therefore, by performing dry etching on the entire substrate, the portion of the photoresist layer removed is removed. The conductive protective layer and the organic EL layer can be removed. If dry etching is used, the edge of the etching can be made sharper, so that the non-uniform film thickness region existing at the edge of the pattern of the conductive protective layer and the organic EL layer can be made narrower. Higher definition patterning is possible.

  As a dry etching method, for example, atmospheric pressure plasma etching, reactive ion etching (RIE), plasma etching using an inert gas, etching using a laser, an ion beam, or the like can be used.

  In reactive ion etching, an organic film undergoes a chemical reaction to become a compound having a low molecular weight, which is removed by vaporization and evaporation. For this reason, when reactive ion etching is used, etching accuracy is high and processing in a short time is possible.

  In addition, when atmospheric pressure plasma etching is used, a vacuum apparatus is not required, and the processing time and cost can be reduced. Atmospheric pressure plasma etching utilizes the fact that organic substances are oxidatively decomposed by oxygen in the atmosphere that has been turned into plasma. At this time, the gas composition of the reaction atmosphere may be arbitrarily adjusted by gas replacement and circulation.

  Further, in dry etching, oxygen alone or a gas containing oxygen may be used. This is because by using oxygen alone or a gas containing oxygen, the organic film can be decomposed and removed by an oxidation reaction, and unnecessary organic substances can be removed.

6). Stripping Step The stripping step in this embodiment is a step of stripping the remaining photoresist layer.

  As a method of peeling the photoresist layer, a method of immersing the substrate in a photoresist stripping solution, a method of spraying the photoresist stripping solution on the substrate in a shower shape, or the like can be used.

  The photoresist stripping solution is not particularly limited as long as it can dissolve the photoresist layer without dissolving the conductive protective layer and the organic EL layer, and the photoresist and the inorganic conductive material to be used are not limited. It differs depending on the combination and the like, and is appropriately selected.

  As such a photoresist stripping solution, the above-described photoresist solvent can be used. When a positive photoresist is used, a photoresist developer can be used as the photoresist stripping solution. Further, as the photoresist stripping solution, for example, the one described in JP-A-2006-318876 may be used.

7). Second electrode layer forming step The second electrode layer forming step in this aspect is a step of forming the second electrode layer on the conductive protective layer exposed after the peeling step.

  The second electrode layer used in this embodiment may be an anode or a cathode. In general, when an organic EL element is produced, it is preferable that the second electrode layer is a cathode because the organic EL element can be stably produced by laminating from the anode side.

  The second electrode layer may or may not have transparency, and is appropriately selected according to the light extraction surface. For example, in the case of the top emission type in the organic EL element shown in FIG. 1 (h), the second electrode layer 9 preferably has transparency. On the other hand, for example, in the case of the bottom emission type in the organic EL element shown in FIG. 1 (h), the second electrode layer 9 is not required to be transparent. For example, when light is extracted from both sides in the organic EL element shown in FIG. 1H, the second electrode layer 9 preferably has transparency.

  For the second electrode layer, the conductive material described in the section of the first electrode layer in the organic EL layer forming step can be used. In particular, in this embodiment, since the conductive protective layer can reduce damage to the organic EL layer due to impact during film formation of the second electrode layer, the conductive material used for the second electrode layer has a melting point. It is preferable that the film can be formed by a film forming method that is high and has high energy during film formation, such as a sputtering method or an ion plating method.

  As such a conductive material, an inorganic oxide such as In—Zn—O (IZO), In—Sn—O (ITO), Zn—O—Al, Zn—Sn—O, or a reaction such as Ag is used. Mention may be made of metals with relatively low properties. In particular, as the conductive material, the inorganic oxide is preferable. This is because the inorganic oxide can be formed by a sputtering method, an ion plating method, or the like, and a dense film can be obtained.

  Further, the thickness of the second electrode layer is not particularly limited, and is appropriately set according to the conductive material to be used. Specifically, the thickness of the second electrode layer is preferably within a range of 40 nm to 500 nm when an inorganic oxide is used, and within a range of 1 nm to 500 nm when a metal is used. preferable. This is because if the thickness of the second electrode layer is too thin, the resistance will be high, and if the thickness of the second electrode layer is too thick, the transmittance may be low.

  Examples of the method for forming the second electrode layer include a CVD method or a PVD method such as a vacuum deposition method, a sputtering method, and an ion plating method. Of these, sputtering and ion plating are preferred. This is because these methods have high film formation energy, so that a material having a high melting point such as the above-described inorganic oxide can be formed, and the film formation efficiency is further improved.

8). Other Steps The method for producing an organic EL device of this aspect is to form at least one color light emitting layer in a pattern, and the organic EL layer forming step, the conductive protective layer forming step, the photoresist layer forming step, By repeating the photoresist layer patterning step and the organic EL layer patterning step a plurality of times, it is possible to form light emitting layers of two colors, three colors, four colors, or five colors in a pattern.

  Moreover, in this aspect, you may perform the washing | cleaning process which wash | cleans the surface of a conductive protective layer after the said peeling process. This is because components remaining on the surface of the conductive protective layer can be removed.

  In the cleaning step, the conductive protective layer surface is cleaned using a cleaning liquid. As the cleaning liquid, a solvent that dissolves the photoresist layer and does not dissolve the conductive protective layer and the organic EL layer can be used. As such a cleaning liquid, the above-described photoresist stripping liquid can be used.

  Furthermore, in this aspect, you may perform the plasma processing process which plasma-processes the surface of a conductive protective layer after the said peeling process. This is because components remaining on the surface of the conductive protective layer can be removed.

  As the introduced gas used in the plasma treatment, a generally used gas can be used. Especially, it is preferable that it is a gas which removes only a photoresist residue and has little influence on a conductive protective layer and an organic EL layer. Examples of such a gas include a gas containing fluorine or a fluorine compound, a gas containing chlorine or a chlorine compound, oxygen, argon, nitrogen, and the like. Two or more kinds of mixed gases may be used as the introduction gas.

II. 2nd aspect The 2nd aspect of the manufacturing method of the organic EL element of this invention is a manufacturing method of the organic EL element which forms the light emitting layer of N color (N is an integer greater than or equal to 2) in pattern, Comprising: 1st electrode Layers are formed, and each of the first color organic EL layer including at least the first color light emitting layer to the (N-1) th color organic EL layer including at least the (N-1) color light emitting layer is patterned. An organic EL of the Nth color including at least the Nth color light emitting layer on a substrate formed and laminated with a conductive protective layer and a photoresist layer containing an inorganic conductive material on the surface of each organic EL layer in this order. An organic EL layer forming step of forming a layer, a conductive protective layer forming step of forming an Nth color conductive protective layer containing an inorganic conductive material on the Nth organic EL layer, and the Nth color Apply a photoresist on the conductive protective layer for A photoresist layer forming step for forming an N-color photoresist layer, and pattern exposure of the N-th color photoresist layer and development to leave the N-th color photoresist layer in the N-color light emitting region A photoresist layer patterning step of patterning the Nth color photoresist layer, and the Nth color conductive protective layer and the Nth color organic layer in a portion where the Nth color photoresist layer is removed. By removing the EL layer, an organic EL layer patterning step for patterning the N-th color conductive protective layer and the N-th color organic EL layer, a peeling step for peeling off each remaining photoresist layer, and And a second electrode layer forming step of forming a second electrode layer on each of the conductive protective layers exposed after the peeling step.

The manufacturing method of the organic EL element of this aspect expresses the step of patterning the Nth color light emitting layer, but the Nth color is also applied to the light emitting layers from the second color to the (N-1) th color. Patterning can be performed in the same manner as the step of patterning the light emitting layer. The first color light emitting layer can also be patterned in the same manner as the patterning process of the Nth color light emitting layer.
Hereinafter, as a specific example, a method for manufacturing an organic EL element in which three color light emitting layers are formed in a pattern will be described.

  That is, in the method for manufacturing an organic EL element in which the three color light emitting layers of this aspect are formed in a pattern, the first color organic EL including at least the first color light emitting layer on the substrate on which the first electrode layer is formed. A first color organic EL layer forming step for forming a layer, and a first color conductive protective layer for forming a first color conductive protective layer containing an inorganic conductive material on the first color organic EL layer Forming a photoresist layer on the first color conductive protective layer to form a first color photoresist layer; and forming the first color photoresist layer. A first color photoresist layer patterning step of patterning the first color photoresist layer so that the first color photoresist layer remains in the first color light emitting region by pattern exposure and development; Photo for the first color The first color organic EL layer patterning step and the first color organic EL layer are removed by removing the first color conductive protective layer and the first color organic EL layer from which the dyst layer has been removed. A second color organic EL layer including at least a second color light emitting layer is formed on a substrate on which the first color conductive protective layer and the first color photoresist layer are formed in a pattern. A color organic EL layer forming step, a second color conductive protective layer forming step of forming a second color conductive protective layer containing an inorganic conductive material on the second color organic EL layer; A photoresist is applied on the two-color conductive protective layer, a second-color photoresist layer forming step for forming a second-color photoresist layer, and pattern-exposing and developing the second-color photoresist layer. Of the second color light emitting region The second-color photoresist layer patterning step for patterning the second-color photoresist layer so that the second-color photoresist layer remains, and the portion where the second-color photoresist layer is removed Patterning the second color organic EL layer by removing the second color conductive protective layer and the second color organic EL layer to pattern the second color conductive protective layer and the second color organic EL layer And a first color organic EL layer, the first color conductive protective layer, and the first color photoresist layer are formed in a pattern, and the second color organic EL layer and the second color are formed. A third color organic EL layer that forms a third color organic EL layer including at least a third color light-emitting layer on a substrate on which a conductive protective layer and a second color photoresist layer are formed in a pattern. A layer forming step, a third color conductive protective layer forming step of forming a third color conductive protective layer containing an inorganic conductive material on the third color organic EL layer, and the third color conductive layer. A third color photoresist layer forming step of applying a photoresist on the protective layer to form a third color photoresist layer, pattern exposing the third color photoresist layer, and developing the third color photoresist layer. A third-color photoresist layer patterning step of patterning the third-color photoresist layer so that the third-color photoresist layer in the three-color light emitting region remains, and the third-color photoresist layer is removed; The third color conductive protective layer and the third color organic EL layer are removed by removing the third color conductive protective layer and the third color organic EL layer. The organic L layer patterning step, stripping step for stripping the remaining first color photoresist layer, the second color photoresist layer and the third color photoresist layer, and the first exposed after the stripping step. And a second electrode layer forming step of forming a second electrode layer on the color conductive protective layer, the second color conductive protective layer, and the third color conductive protective layer. .

The manufacturing method of the organic EL element of this aspect is demonstrated referring drawings.
2-4 is process drawing which shows an example of the manufacturing method of the organic EL element of this aspect. First, the first electrode layer 2 is formed in a pattern on the substrate 1, the insulating layer 3 is formed between the patterns of the first electrode layer 2, and the first color is formed on the first electrode layer 2 and the insulating layer 3. The positive hole injection layer 4a and the first color light emitting layer 5a are formed to form the first color organic EL layer 6a (FIG. 2A, the first color organic EL layer forming step). Next, a first color conductive protective layer 7a is formed on the first color light emitting layer 5a (FIG. 2B, first color conductive protective layer forming step). Next, a positive photoresist is applied on the first color conductive protective layer 7a to form a first color photoresist layer 8a (FIG. 2C, first color photoresist layer forming step). . Next, the first color photoresist layer 8a is subjected to pattern exposure through the photomask 11 so that at least the first color photoresist layer 8a in the first color light emitting region 10a remains, and then developed with a photoresist developer. Then, a patterned first color photoresist layer 8a 'is formed by washing (FIGS. 2D and 2E, first color photoresist layer patterning step). Next, by removing the first color conductive protective layer, the first color light emitting layer, and the first color hole injection layer exposed by the removal of the first color photoresist layer, the patterned first The color conductive protective layer 7a ′, the first color light emitting layer 5a ′, and the first color hole injection layer 4a ′ are formed (FIG. 2F, the first color organic EL layer patterning step).

  Next, the substrate 1 on which the patterned first color photoresist layer 8a ′, the first color conductive protective layer 7a ′, the first color light emitting layer 5a ′, and the first color hole injection layer 4a ′ are formed. A second color hole injection layer 4b and a second color light emitting layer 5b are formed thereon to form a second color organic EL layer 6b (FIG. 2G, second color organic EL layer forming step). . Next, the second color conductive protective layer 7b is formed on the second color light emitting layer 5b (FIG. 2H, second color conductive protective layer forming step). Next, a positive photoresist is applied on the second color conductive protective layer 7b to form a second color photoresist layer 8b (FIG. 3A, second color photoresist layer forming step). . Next, the second color photoresist layer 8b is subjected to pattern exposure through the photomask 11 so that at least the second color photoresist layer 8b in the second color light emitting region 10b remains, and then developed with a photoresist developer. Then, by washing, a patterned second color photoresist layer 8b 'is formed (FIGS. 3B and 3C, second color photoresist layer patterning step). Next, by removing the second color conductive protective layer, the second color light emitting layer, and the second color hole injection layer exposed by the removal of the second color photoresist layer, the patterned second layer is removed. A color conductive protective layer 7b ′, a second color light emitting layer 5b ′, and a second color hole injection layer 4b ′ are formed (FIG. 3D, organic EL layer patterning step of the second color).

  Next, a patterned first color photoresist layer 8a ', a first color conductive protective layer 7a', a first color light emitting layer 5a ', a first color hole injection layer 4a', and a patterned first color For the third color on the substrate 1 on which the two-color photoresist layer 8b ', the second color conductive protective layer 7b', the second color light emitting layer 5b 'and the second color hole injection layer 4b' are formed. The hole injection layer 4c and the third color light emitting layer 5c are formed to form the third color organic EL layer 6c (FIG. 3E, the third color organic EL layer forming step). Next, a third color conductive protective layer 7c is formed on the third color light emitting layer 5c (FIG. 3F, a third color conductive protective layer forming step). Next, a positive photoresist is applied on the third color conductive protective layer 7c to form a third color photoresist layer 8c (FIG. 3G, third color photoresist layer forming step). . Next, the third color photoresist layer 8c is subjected to pattern exposure through the photomask 11 so that at least the third color photoresist layer 8c in the third color light emitting region 10c remains, and then developed with a photoresist developer. Then, a patterned third color photoresist layer 8c ′ is formed by washing (FIGS. 4A and 4B, a third color photoresist layer patterning step). Next, by removing the third color conductive protective layer, the third color light emitting layer, and the third color hole injection layer exposed by the removal of the third color photoresist layer, the patterned third layer is removed. A color conductive protective layer 7c ′, a third color light emitting layer 5c ′, and a third color hole injection layer 4c ′ are formed (FIG. 4C, organic EL layer patterning step of the second color).

Next, the first-color photoresist layer 8a ′, the second-color photoresist layer 8b ′, and the third-color photoresist layer 8c ′ located in the uppermost layer are stripped (FIG. 4D, stripping step).
Finally, the second electrode layer 9 is formed on the first color conductive protective layer 7a ′, the second color conductive protective layer 7b ′, and the third color conductive protective layer 7c ′ (FIG. 4E). Second electrode layer forming step).

  In this aspect, since each conductive protective layer is formed on each organic EL layer to be patterned before each photoresist layer is formed, the photoresist is not directly applied on each organic EL layer. When patterning the second color organic EL layer, the second color organic EL layer, the first color conductive protective layer, and the first color photoresist layer are formed on the second color organic EL layer. Since the organic EL layer and the second color conductive protective layer are formed and the photoresist is applied on the second color conductive protective layer, the first color organic EL layer is in contact with the second color photoresist layer. I don't have to. Further, when the third color organic EL layer is patterned, similarly, the first color organic EL layer and the second color organic EL layer do not come into contact with the third color photoresist layer. Moreover, since each photoresist layer is peeled after patterning of all organic EL layers, the surface of each patterned organic EL layer is exposed to a photoresist component, for example, a photosensitive agent, an additive, a resin, or the like. Can be prevented. Therefore, each conductive protective layer can prevent the photoresist component from coming into contact with each organic EL layer, and can prevent a decrease in light emission characteristics and the like due to the photoresist component.

  Further, as described above, when patterning the organic EL layer of the second color, the patterned first color organic EL layer, the first color conductive protective layer, and the first color photoresist layer are formed. Since the second color organic EL layer and the second color conductive protective layer are formed, damage to the first color organic EL layer when the second color organic EL layer is removed can be reduced. . Similarly, when patterning the organic EL layer of the third color, damage to the organic EL layer of the first color and the organic EL layer of the second color when the organic EL layer of the third color is removed similarly. Can be reduced.

  Further, in this embodiment, since the second electrode layer is formed on each conductive protective layer, even when the second electrode layer is formed by sputtering, plasma gas ions at the time of sputtering, sputtered particles In addition, the impact on the organic EL layer due to ionized electrons or the like can be reduced. As a result, it is possible to suppress a decrease in the characteristics of the organic EL layer such as the element characteristics such as the light emission characteristics and the electron injection characteristics due to the impact when forming the second electrode layer.

  Therefore, in this embodiment, it is possible to produce an organic EL element that is excellent in element characteristics such as light emission characteristics and lifetime characteristics, and organic EL layer characteristics such as electron injection characteristics.

  Further, in the second color photoresist layer patterning step, the second color photoresist layer is patterned so that the second color photoresist layer in the second color light emitting region remains, so the patterned first color The second color photoresist layer does not remain on the organic EL layer. In other words, the photoresist layer laminated on the patterned first color organic EL layer is only the first color photoresist layer. Further, the portion of the second color organic EL layer exposed by the removal of the second color photoresist layer is also removed in the second color organic EL layer patterning step, so that the first color organic EL layer is removed. On top of this, the organic EL layer of the second color does not remain. Therefore, it is possible to avoid a state in which an extra layer is stacked on the patterned first-color organic EL layer. As a result, it is possible to eliminate film thickness unevenness caused by stacking a plurality of layers.

  Further, only the first color photoresist layer to be peeled off in the peeling step is laminated on the first color conductive protective layer, and this first color photoresist layer is formed by each organic EL layer. After the patterning step, it will be located in the uppermost layer. Therefore, the first color photoresist layer can be easily and quickly peeled off. Similarly, the second-color photoresist layer and the third-color photoresist layer are positioned in the uppermost layer after each organic EL layer patterning step, and can be easily and quickly peeled off.

  In addition, since the conductive protective layer in this embodiment contains an inorganic conductive material and has a relatively low electric resistance, an organic EL element exhibiting good current-voltage characteristics can be obtained.

The first color photoresist layer patterning step, the first color organic EL layer patterning step, the second color photoresist layer patterning step, the second color organic EL layer patterning step, and the third color photoresist layer patterning step. The process, the third color organic EL layer patterning step, the peeling step, and the second electrode layer forming step are the photoresist layer patterning step, the organic EL layer patterning step, the peeling step, and the second electrode layer forming step of the first aspect. Since these are the same as each other, description thereof is omitted here.
Hereafter, each process other than the above of the manufacturing method of the organic EL element of this aspect is demonstrated.

1. First Color Organic EL Layer Forming Step In the first color organic EL layer forming step, the first color organic EL layer including at least a first color light emitting layer on the substrate on which the first electrode layer is formed. Is a step of forming.

  In this embodiment, the light emitting layer of a plurality of colors can be formed in a pattern by patterning a plurality of times using a photolithography method. Therefore, different types of light emitting materials are used in the first, second, and third color organic EL layer forming steps. At this time, from the viewpoint of reducing manufacturing costs, it is preferable to form a light emitting layer by applying a light emitting layer forming coating solution.

  The first color organic EL layer is composed of a first color hole injection layer and a first color light emitting layer. In the second color organic EL layer forming step described later, A second color hole injection layer forming coating solution is applied onto the substrate on which the organic EL layer, the first color conductive protective layer, and the first color photoresist layer are formed in a pattern, and the second color is applied. When forming the positive hole injection layer, the first color positive hole injection layer is preferably insoluble in the solvent of the second color positive hole injection layer forming coating solution. As a result, during the formation of the second color hole injection layer, the solvent of the second color hole injection layer forming coating solution comes into contact with the edge of the pattern of the first color hole injection layer. However, since the first color hole injection layer is not dissolved, the second color hole injection layer can be stably laminated.

  Further, the first color organic EL layer is composed of a first color hole injection layer and a first color light emitting layer. In the third color organic EL layer forming step described later, A third color hole injection layer forming coating solution is applied onto a substrate on which a colored organic EL layer, a first color conductive protective layer and a first color photoresist layer are formed in a pattern. When forming the three-color hole injection layer, the first color hole injection layer is preferably insoluble in the solvent of the third-color hole injection layer forming coating solution.

  The first color hole injection layer is insoluble in the solvent of the second color hole injection layer forming coating solution or the solvent of the third color hole injection layer forming coating solution. This is the same as that described in the section “(1) Organic EL layer (i) Two organic layers” in the organic EL layer forming step of the first aspect, and the description thereof is omitted here. .

  The first color organic EL layer is composed of a first color hole injection layer and a first color light emitting layer. In the second color organic EL layer forming step described later, the second color When a second color light emitting layer forming coating solution is applied onto the hole injection layer for forming a second color light emitting layer, the first color light emitting layer is applied to the second color light emitting layer forming coating. It may be insoluble, hardly soluble or soluble in the liquid solvent. Before the second color light emitting layer is formed, the first color light emitting layer is covered with the second color hole injection layer, and thus is soluble in the solvent of the second color light emitting layer forming coating solution. However, it does not come into contact with the solvent and does not dissolve.

  The first color organic EL layer is composed of a first color hole injection layer and a first color light emitting layer. In the third color organic EL layer forming step described later, When the third color light-emitting layer is formed by applying the third color light-emitting layer forming coating solution on the three-color hole injection layer, the first color light-emitting layer is used for forming the third color light-emitting layer. It may be insoluble, hardly soluble or soluble in the solvent of the coating solution.

  In addition, since it is the same as that of what was described in the term of the organic EL layer formation process of the said 1st aspect about the other point of the organic EL layer formation process of the 1st color, description here is abbreviate | omitted.

2. First color conductive protective layer forming step The first color conductive protective layer forming step in this aspect is a step of forming a first color conductive protective layer on the first color organic EL layer.

  In the second-color organic EL layer forming step described later, the second-color organic EL layer, the first-color conductive protective layer, and the first-color photoresist layer are formed on the substrate in a pattern. When the second color hole injection layer is formed by applying the color hole injection layer forming coating solution, the first color conductive protective layer is applied to the second color hole injection layer forming coating. It is preferably insoluble in the solvent of the working solution. Thus, when the second color hole injection layer is formed, the solvent of the second color hole injection layer forming coating solution comes into contact with the end of the pattern of the first color conductive protective layer. This is because, since the first color conductive protective layer is not dissolved, the second color hole injection layer can be stably laminated.

  In order to make the first color conductive protective layer insoluble in the solvent of the second color hole injection layer forming coating solution, the first color conductive protective layer and the second color hole injection A material having different solubility may be used for the layer.

  Further, in the second color conductive protective layer forming step described later, a second color conductive protective layer forming coating solution is applied onto the second color organic EL layer to form a second color conductive protective layer. In this case, the first color conductive protective layer may be insoluble, hardly soluble or soluble in the solvent of the second color conductive protective layer forming coating solution. Before the second color conductive protective layer is formed, the first color conductive protective layer is covered with the organic EL layer of the second color. This is because even if it is soluble, it does not come into contact with the solvent and does not dissolve.

  In addition, since it is the same as that of what was described in the term of the conductive protective layer formation process of the said 1st aspect about the other point of the conductive protective layer formation process for 1st colors, description here is abbreviate | omitted.

3. First Color Photoresist Layer Formation Step The first color photoresist layer formation step in this aspect is a step of applying a photoresist on the first color conductive protective layer to form a first color photoresist layer. is there.
In this embodiment, three types of first color, second color, and third color are used for the photoresist layer, but these are all used for convenience and are all the same photoresist layer. May be.

  In the second-color organic EL layer forming step described later, the second-color organic EL layer, the first-color conductive protective layer, and the first-color photoresist layer are formed on the substrate in a pattern. When the color hole injection layer forming coating solution is applied to form the second color hole injection layer, the first color photoresist layer is applied to the second color hole injection layer forming coating. It is preferably insoluble in the solvent of the working solution. Thus, when the second color hole injection layer is formed, even if the solvent of the second color hole injection layer forming coating solution contacts the first color photoresist layer, the first color This is because the second photoresist hole injection layer can be stably laminated because the photoresist layer for use is not dissolved.

  In order to make the first color photoresist layer insoluble in the solvent of the coating solution for forming the second color hole injection layer, the first color photoresist layer and the second color hole injection layer are used. In this case, materials having different solubility may be used.

  Further, the first color photoresist layer may be insoluble, hardly soluble or soluble in the photoresist solvent used in the second color photoresist layer forming step. Before forming the second color photoresist layer, the first color photoresist layer is covered with the second color organic EL layer and the second color conductive protective layer, and is therefore soluble in the photoresist solvent. However, it does not come into contact with the solvent and does not dissolve.

  Since the other points of the first color photoresist layer forming step are the same as those described in the section of the photoresist layer forming step of the first aspect, description thereof is omitted here.

4). Second color organic EL layer forming step In the second color organic EL layer forming step in this embodiment, the first color organic EL layer, the first color conductive protective layer, and the first color photoresist layer are patterned. In this step, an organic EL layer of the second color including at least the second color light emitting layer is formed on the formed substrate.

  On the substrate on which the first color organic EL layer, the first color conductive protective layer, and the first color photoresist layer are formed in a pattern, a second color hole injection layer forming coating solution is applied. When the second color hole injection layer is formed, the solvent of the second color hole injection layer forming coating solution is the first color organic EL layer, the first color conductive protective layer, and the first color. It is preferable that the one-color photoresist layer is not dissolved. This is because when the second color hole injection layer is formed, the solvent of the second color hole injection layer forming coating solution is the first color organic EL layer, the first color conductive protective layer. This is because it comes into contact with the first color photoresist layer. Specifically, during the formation of the second color hole injection layer, the solvent of the second color hole injection layer forming coating solution is changed to the first color organic EL layer and the first color conductive layer. The edge of the pattern of the protective layer and the surface and edge of the pattern of the first color photoresist layer are contacted.

  In the above case, the organic EL layer of the first color is compared with the area where the solvent of the coating solution for forming the hole injection layer for the second color is in contact with the surface and end of the pattern of the first color photoresist layer. And the area which contacts the edge part of the pattern of the electrically conductive protective layer for 1st colors is very small. Therefore, when the hole injection layer for the second color is stably laminated, or when the minimum dimension value of one pixel is smaller than 100 μm, the coating solution for forming the hole injection layer for the second color It is very effective that the solvent does not dissolve the first color organic EL layer and the first color conductive protective layer.

  In addition, a second color light emitting layer forming coating solution is applied onto a substrate on which a first color organic EL layer, a first color conductive protective layer, and a first color photoresist layer are formed in a pattern. When the second color light emitting layer is formed, the solvent of the second color light emitting layer forming coating solution is preferably one that does not dissolve the first color photoresist layer.

  For example, when a general novolak positive photoresist is used for the first color photoresist layer, the solvent may be the light emitting layer forming coating described in the organic EL layer forming step of the first aspect. The solvent used for the working liquid is preferably used.

  The second color organic EL layer is composed of a second color hole injection layer and a second color light emitting layer. In the third color organic EL layer forming step described later, A second color hole injection layer forming coating solution is applied onto the substrate on which the organic EL layer, the second color conductive protective layer, and the second color photoresist layer are formed in a pattern, and the second color is applied. When forming the positive hole injection layer, the second color hole injection layer is preferably insoluble in the solvent of the third color positive hole injection layer forming coating solution.

  In addition, about making the hole injection layer for 2nd colors insoluble with respect to the solvent of the coating liquid for 3rd color hole injection layer formation, the organic electroluminescent layer formation process of the said 1st aspect WHEREIN: Since it is the same as that described in the section of (1) Organic EL layer (i) Two organic layers, description thereof is omitted here.

  The second color organic EL layer is composed of a second color hole injection layer and a second color light emitting layer. In the third color organic EL layer forming step described later, When the third color light emitting layer is formed by applying the third color light emitting layer forming coating solution on the three color hole injection layer, the second color light emitting layer is used for forming the third color light emitting layer. It may be insoluble, hardly soluble or soluble in the solvent of the coating solution. Before the formation of the third color light emitting layer, the second color light emitting layer is covered with the third color hole injection layer, so that it is soluble in the solvent of the third color light emitting layer forming coating solution. However, it does not come into contact with the solvent and does not dissolve.

  The other points of the second color organic EL layer forming step are the same as those described in the section of the organic EL layer forming step of the first aspect, and the description thereof is omitted here.

5. Second color conductive protective layer forming step The second color conductive protective layer forming step in this aspect is a step of forming a second color conductive protective layer on the second color organic EL layer.

  In the case of forming the second color conductive protective layer by applying the second color conductive protective layer forming coating liquid on the second color organic EL layer, the second color conductive protective layer forming coating is applied. The solvent of the working solution may or may not dissolve the first color organic EL layer, the first color conductive protective layer, and the first color photoresist layer. Before forming the second color conductive protective layer, the first color organic EL layer, the first color conductive protective layer, and the first color photoresist layer are covered with the second color organic EL layer. This is because even if it is soluble in the solvent of the coating solution for forming the second color conductive protective layer, it does not come into contact with the solvent and does not dissolve.

  Further, in the third color organic EL layer forming step to be described later, on the substrate on which the second color organic EL layer, the second color conductive protective layer, and the second color photoresist layer are formed in a pattern, When the third color hole injection layer forming coating liquid is applied to form the third color hole injection layer, the second color conductive protective layer is formed by forming the third color hole injection layer. It is preferably insoluble in the solvent of the coating liquid for coating. Thus, when the third color hole injection layer is formed, the solvent of the third color hole injection layer forming coating solution comes into contact with the end of the pattern of the second color conductive protective layer. This is because the second color conductive protective layer is not dissolved, and thus the third color hole injection layer can be stably laminated.

  In order to make the second color conductive protective layer insoluble in the solvent of the third color hole injection layer forming coating solution, the second color conductive protective layer and the third color hole injection layer are used. In this case, materials having different solubility may be used.

  Further, a third color conductive protective layer is formed by applying a third color conductive protective layer forming coating liquid on the third color organic EL layer in the third color conductive protective layer forming step described later. In this case, the second color conductive protective layer may be insoluble, hardly soluble or soluble in the solvent of the third color conductive protective layer forming coating solution. Before the third color conductive protective layer is formed, the second color conductive protective layer is covered with the third color organic EL layer. This is because even if it is soluble, it does not come into contact with the solvent and does not dissolve.

  The other points of the second color conductive protective layer forming step are the same as those described in the section of the first aspect of the conductive protective layer forming step, and the description thereof is omitted here.

6). Second Color Photoresist Layer Forming Step The second color photoresist layer forming step in this embodiment is a step of applying a photoresist on the second color conductive protective layer and forming a second color photoresist layer. is there.

  The photoresist solvent used in this step may or may not dissolve the first color organic EL layer, the first color conductive protective layer, and the first color photoresist layer. . Before forming the second color photoresist layer, the first color organic EL layer, the first color conductive protective layer, and the first color photoresist layer are the second color organic EL layer and the second color conductive protective layer. Because it is covered with a layer, even if it is soluble in a photoresist solvent, it does not come into contact with the solvent and does not dissolve.

  Further, in the third color organic EL layer forming step to be described later, on the substrate on which the second color organic EL layer, the second color conductive protective layer, and the second color photoresist layer are formed in a pattern, When the third color hole injection layer is formed by applying the third color hole injection layer forming coating solution, the second color photoresist layer is formed by forming the third color hole injection layer. It is preferably insoluble in the solvent of the coating liquid for coating. Thus, when the third color hole injection layer is formed, even if the solvent of the third color hole injection layer forming coating solution contacts the second color photoresist layer, the second color This is because the third photoresist layer can be stably laminated because the photoresist layer for use is not dissolved.

  In order to make the second color photoresist layer insoluble in the solvent of the third color hole injection layer forming coating solution, the second color photoresist layer and the third color hole injection layer are used. In this case, materials having different solubility may be used.

  Further, the second color photoresist layer may be insoluble, hardly soluble or soluble in the photoresist solvent used in the third color photoresist layer forming step. Before the formation of the third color photoresist layer, the second color photoresist layer is covered with the third color organic EL layer and the third color conductive protective layer, so that it is soluble in the photoresist solvent. However, it does not come into contact with the solvent and does not dissolve.

  Since the other points of the second color photoresist layer forming step are the same as those described in the section of the photoresist layer forming step of the first aspect, description thereof is omitted here.

7). Step of forming organic EL layer of third color In the step of forming organic EL layer of the third color in this aspect, the first color of organic EL layer, the first color conductive protective layer, and the first color photoresist layer are patterned. And a third color light emitting layer including at least a third color light emitting layer on the substrate on which the second color organic EL layer, the second color conductive protective layer, and the second color photoresist layer are formed in a pattern. This is a step of forming an organic EL layer.

  The first color organic EL layer, the first color conductive protective layer and the first color photoresist layer are formed in a pattern, and the second color organic EL layer, the second color conductive protective layer and the second color are formed. When the third color hole injection layer is formed by applying the third color hole injection layer forming coating solution on the substrate on which the photoresist layer for the pattern is formed in a pattern, the third color The solvent of the coating solution for forming the hole injection layer for the first color is the first color organic EL layer, the first color conductive protective layer, the first color photoresist layer, the second color organic EL layer, and the second color. It is preferable that the conductive protective layer and the second color photoresist layer are not dissolved.

  Since the other points of the third color organic EL layer forming step are the same as those described in the section of the organic EL layer forming step of the first aspect, description thereof is omitted here.

8). Step of forming a third color conductive protective layer The step of forming a third color conductive protective layer in the present invention is a step of forming a third color conductive protective layer on the third color organic EL layer.

  When the third color conductive protective layer is formed by applying the third color conductive protective layer forming coating solution on the third color organic EL layer, the third color conductive protective layer forming coating is applied. The solvent of the working solution is the first color organic EL layer, the first color conductive protective layer, the first color photoresist layer, the second color organic EL layer, the second color conductive protective layer, and the second color. The photoresist layer may be dissolved or may not be dissolved. Before forming the second color conductive protective layer, the first color organic EL layer, the first color conductive protective layer, the first color photoresist layer, the second color organic EL layer, and the second color conductive protective layer. Since the second color photoresist layer is covered with the third color organic EL layer, even if it is soluble in the solvent of the third color conductive protective layer forming coating solution, the solvent It is because it does not contact and does not melt.

  Since the other points of the third color conductive protective layer forming step are the same as those described in the section of the conductive protective layer forming step of the first aspect, description thereof is omitted here.

9. Third Color Photoresist Layer Forming Step The third color photoresist layer forming step in the present invention is a step of forming a third color photoresist layer by applying a photoresist on the third color conductive protective layer. is there.

  The photoresist solvent used in this step includes a first color organic EL layer, a first color conductive protective layer, a first color photoresist layer, a second color organic EL layer, a second color conductive protective layer, and The second color photoresist layer may or may not dissolve. Before forming the second color photoresist layer, the first color organic EL layer, the first color conductive protective layer, the first color photoresist layer, the second color organic EL layer, and the second color conductive protective layer. Since the second color photoresist layer is covered with the third color organic EL layer and the third color conductive protective layer, even if it is soluble in the photoresist solvent, it comes into contact with the solvent. This is because it does not dissolve.

  Since the other points of the third color photoresist layer forming step are the same as those described in the section of the photoresist layer forming step of the first aspect, description thereof is omitted here.

10. Other Steps In this embodiment, after the peeling step, a cleaning step for cleaning the surface of each conductive protective layer may be performed. Moreover, you may perform the plasma processing process which plasma-processes the surface of each conductive protective layer after the said peeling process.
Note that the cleaning process and the plasma treatment process are the same as those described in the section of the first aspect, and thus the description thereof is omitted here.

B. Organic EL Element Next, the organic EL element of the present invention will be described.
The organic EL device of the present invention includes a substrate, a first electrode layer formed on the substrate, an organic EL layer formed in a pattern on the first electrode layer and including at least a light emitting layer, and the organic EL A conductive protective layer formed in a pattern on the layer and containing an inorganic conductive material, and a second electrode layer formed on the conductive protective layer, and a pattern shape of the organic EL layer; The conductive protective layer has the same pattern shape.

  The organic EL element of the present invention will be described with reference to the drawings. FIG. 5 is a schematic cross-sectional view showing an example of the organic EL element of the present invention. As illustrated in FIG. 5, in the organic EL element 20, the first electrode layer 22 is formed in a pattern on the substrate 21, and the insulating layer 23 is formed between the patterns of the first electrode layer 22. On the electrode layer 22, an organic EL layer 26 composed of a patterned hole injection layer 24 and a light emitting layer 25, and a patterned conductive protective layer 27 are sequentially laminated, and a second electrode is formed on the conductive protective layer 27. Layer 29 is formed. The pattern shape of the organic EL layer 26 and the pattern shape of the conductive protective layer 27 are the same.

  In the present invention, since the conductive protective layer is formed on the organic EL layer, and the patterns of the organic EL layer and the conductive protective layer have the same shape, the organic EL element of the present invention is produced using a photolithography method. In this case, for example, an organic EL element can be obtained by the process as shown in FIG. 1 described in the above-mentioned section “A. Manufacturing method of organic EL element”.

  When an organic EL element is produced by the process illustrated in FIG. 1, a photoresist layer is formed on the organic EL layer and the conductive protective layer, so that a photoresist is directly applied on the organic EL layer. There is no. Further, after patterning the organic EL layer, only the photoresist layer formed on the conductive protective layer is peeled off, so that the photoresist component can be prevented from coming into contact with the organic EL layer. Thereby, it can prevent that the organic EL layer surface is contaminated with a photoresist component, for example, a photosensitizer, an additive, a resin or the like. Therefore, when the organic EL element is manufactured by using a photolithography method, the configuration of the present invention can avoid a decrease in the light emission characteristics, life characteristics, and the like of the organic EL layer due to the photoresist component.

  In the present invention, since the conductive protective layer is formed between the organic EL layer and the second electrode layer, when the second electrode layer is formed by sputtering or the like, plasma during sputtering is used. The impact on the organic EL layer due to gas ions, sputtered particles, and ionized electrons can be reduced. As a result, it is possible to suppress a decrease in the characteristics of the organic EL layer such as the element characteristics such as the light emission characteristics and the electron injection characteristics due to the impact when forming the second electrode layer.

  Therefore, in the present invention, by forming a conductive protective layer on the organic EL layer, an organic EL element having excellent characteristics of the organic EL layer such as element characteristics such as light emission characteristics and lifetime characteristics and electron injection characteristics is obtained. It is possible.

  Furthermore, since the conductive protective layer in the present invention contains an inorganic conductive material and has a relatively low electrical resistance, the organic EL layer can be protected while maintaining good current-voltage characteristics.

  In addition, as described above, the conductive protective layer contains an inorganic conductive material and thus has a relatively high conductivity. However, since the pattern shape of the conductive protective layer is the same as the pattern shape of the organic EL layer, It is possible to avoid the occurrence of crosstalk between the patterns of the adjacent organic EL layers due to leakage current flowing in the surface direction.

  The organic EL element of the present invention may be any of a bottom emission type, a top emission type, and a dual emission type. Among these, a top emission type or a double-sided emission type is preferable. In general, a transparent electrode such as IZO or ITO is formed by a method having a high film formation energy such as a sputtering method or an ion plating method. In the present invention, the conductive protective layer can mitigate the impact on the organic EL layer during the formation of the second electrode layer, which is useful when the second electrode layer is a transparent electrode.

  Since the conductive protective layer, the organic EL layer, the first electrode layer, the second electrode layer, and the substrate are described in the above section “A. Method for manufacturing organic EL element”, description thereof is omitted here.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not restrict | limited by these Examples.

[Example 1]
(Film formation of hole injection layer for first color)
A patterned ITO glass substrate having a thickness of 6 inches and a thickness of 0.7 mm was washed to obtain a substrate and a first electrode. A coating solution for forming a hole injection layer for the first color having the following composition is applied onto this substrate by a spin coater, heated and dried at 150 ° C. for 10 minutes, cured, and transparent with a thickness of 80 nm. A hole injection layer for one color was obtained.
<Composition of coating liquid for forming hole injection layer for first color>
・ Deionized water 96.7 wt%
・ PEDOT / PSS (manufactured by Bayer) 3wt%
-Organoalkoxysilane (TSL8350 manufactured by Toshiba Silicone Co., Ltd.) 0.3wt%

(Deposition of first color light emitting layer)
As a first color light emitting layer, a first color light emitting layer forming coating solution having the following composition is applied onto the first color hole injection layer by a spin coater, and heated and dried at 130 ° C. for 10 minutes. A light emitting layer having a thickness of 80 nm was obtained.
<Composition of coating liquid for forming first color light emitting layer>
・ Monochlorobenzene 97.98wt%
・ Polyvinylcarbazole 1.4wt%
・ Oxadiazole 0.6wt%
・ Dicyanomethylenepyran derivative 0.02wt%

(Formation of conductive protective layer for first color)
A Ca: Ag mixed film (10 nm) / Ag (40 nm) was formed on the first color light emitting layer by a vacuum deposition method.

(Formation of first color photoresist layer)
A positive photoresist solution (OFPR-800 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is dropped on the conductive protective layer for the first color, applied by a spin coater, and further prebaked at 110 ° C. for 5 minutes. A photoresist layer of about 1.5 μm was obtained.

(First color light emitting part patterning)
Then, it installed in the alignment exposure machine with the exposure mask, and irradiated the ultraviolet-ray to the part which wants to remove light emitting layers other than a 1st color light emission part. The resist was developed with a resist developer (NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) and then washed with water to remove the photoresist in the exposed area. Post-baking at 110 ° C. for 5 minutes, the first color conductive protective layer where the photoresist layer has been removed is removed by plasma etching using argon gas, and then the first color is etched by reactive ion etching using oxygen plasma. The positive hole injection layer and the first color light emitting layer were removed. Thereby, the board | substrate with which the 1st color light emission part was formed in pattern shape was obtained.

(Deposition of second color hole injection layer)
A second color hole injection layer forming coating solution having the same composition as the first color hole injection layer forming coating solution is similarly dropped onto the substrate obtained as described above, and applied by spin coating. Then, the film was cured by heating and drying to obtain a transparent second color hole injection layer having a thickness of 80 nm. The same coating liquid was used when the first color hole injection layer was formed and when the second color hole injection layer was formed. However, since the first color hole injection layer was cured, the second color Even when the hole injection layer forming coating solution was applied, the first color hole injection layer was not eluted into the second color hole injection layer forming coating solution.

(Deposition of second color light emitting layer)
As a second color light emitting layer, a second color light emitting layer forming coating solution having the following composition is applied onto the second color hole injection layer by a spin coater, and heated and dried at 130 ° C. for 10 minutes. A light emitting layer having a thickness of 80 nm was obtained.
<Composition of coating liquid for forming second color light emitting layer>
・ Monochlorobenzene 97.98wt%
・ Polyvinylcarbazole 1.4wt%
・ Oxadiazole 0.6wt%
・ Coumarin derivative 0.02wt%

(Deposition of conductive protective layer for second color)
On the second color light emitting layer, a Ca: Ag mixed film (10 nm) / Ag (40 nm) was formed by vacuum deposition.

(Deposition of second color photoresist layer)
A positive photoresist solution (OFPR-800 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is dropped on the conductive protective layer for the second color, applied by a spin coater, and further prebaked at 110 ° C. for 5 minutes. A photoresist layer of about 1.5 μm was obtained.

(Second color light emitting part patterning)
Then, it installed in the alignment exposure machine with the exposure mask, and irradiated the ultraviolet-ray to the part which wants to remove light emitting layers other than a 2nd color light emission part. The resist was developed with a resist developer (NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) and then washed with water to remove the photoresist in the exposed area. Post-baked at 110 ° C. for 5 minutes, the second color conductive protective layer where the photoresist layer was removed by plasma etching using argon gas was removed, and then the second color was etched by reactive ion etching using oxygen plasma. The positive hole injection layer and the second color light emitting layer were removed. Thereby, the board | substrate with which the 1st color light emission part and the 2nd color light emission part were formed in pattern shape was obtained.

(Deposition of hole injection layer for third color)
A third color hole injection layer forming coating solution having the same composition as the first and second color hole injection layer forming coating solution is similarly dropped onto the substrate obtained as described above, and spin coating is performed. Was applied and cured by heating and drying to obtain a transparent third color hole injection layer having a thickness of 80 nm. The same coating solution was used when forming the first and second color hole injection layers and when forming the third color hole injection layers, but the first and second color hole injection layers were cured. Therefore, even if the third color hole injection layer forming coating liquid is applied, the first color hole injection layer and the second color hole injection layer are applied to form the third color hole injection layer. It did not elute into the liquid.

(Deposition of third color light emitting layer)
As a third color light emitting layer, a third color light emitting layer forming coating solution having the following composition is applied on the third color hole injection layer by a spin coater, and heated and dried at 130 ° C. for 10 minutes. A light emitting layer having a thickness of 80 nm was obtained.
<Composition of third color light emitting layer forming coating solution>
・ Monochlorobenzene 97.98wt%
・ Polyvinylcarbazole 1.4wt%
・ Oxadiazole 0.6wt%
・ Perylene derivative 0.02wt%

(Formation of conductive protective layer for third color)
A Ca: Ag mixed film (10 nm) / Ag (40 nm) was formed on the third color light emitting layer by a vacuum deposition method.

(Deposition of third color photoresist layer)
A positive photoresist solution (OFPR-800 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is dropped on the conductive protective layer for the third color, applied by a spin coater, and further prebaked at 110 ° C. for 5 minutes. A photoresist layer of about 1.5 μm was obtained.

(Third-color light emitting part patterning)
Then, it installed in the alignment exposure machine with the exposure mask, and irradiated the ultraviolet-ray to the part which wants to remove light emitting layers other than a 3rd color light emission part. The resist was developed with a resist developer (NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) and then washed with water to remove the photoresist in the exposed area. After baking at 110 ° C. for 5 minutes, the third color conductive protective layer where the photoresist layer has been removed is removed by plasma etching using argon gas, and then the third color is obtained by reactive ion etching using oxygen plasma. The positive hole injection layer and the third color light emitting layer were removed. Thereby, the board | substrate with which the 1st color light emission part, the 2nd color light emission part, and the 3rd color light emission part were formed in pattern shape was obtained.

(Photoresist peeling)
The substrate was washed with acetone, the photoresist layer was removed, and a patterned organic EL layer was obtained. Then, it was dried at 130 ° C. for 1 hour.

(Formation of second electrode)
Further, on the obtained substrate, Ca was formed as a second electrode layer with a thickness of 10 nm and Ag as a protective electrode with a thickness of 300 nm by vacuum evaporation to produce an organic EL element.

[Example 2]
In the formation of the first color conductive protective layer, the second color conductive protective layer, and the third color conductive protective layer, lithium fluoride was formed to a thickness of 3 nm by vacuum deposition, and Ca (10 nm) was used as the second electrode. ) / Ag (300 nm) was prepared in the same manner as in Example 1 except that the film was formed by vacuum deposition.

[Evaluation]
In the organic EL elements produced in Example 1 and Example 2, the first electrode (ITO electrode) was connected to the positive electrode of the power source, the second electrode (Ag protective electrode) was connected to the negative electrode of the power source, and a DC voltage was applied. As a result, light emission was confirmed from the first color, second color, and third color light emitting sections when a positive voltage was applied. In Example 1 and Example 2, an organic EL element in which the light emitting layer was patterned with high definition using various conductive protective layers could be produced relatively easily.

[Example 3]
An organic EL element for simply evaluating the performance of the organic EL element of Example 1 was produced.
(Hole injection layer deposition)
A patterned ITO glass substrate having a thickness of 1 inch and a thickness of 0.7 mm was washed to obtain a substrate and a first electrode. On this substrate, a hole injection layer forming coating solution having the same composition as the first color hole injection layer forming coating solution used in Example 1 was applied by a spin coater and heated at 150 ° C. for 10 minutes. A drying treatment was performed and cured to obtain a transparent hole injection layer having a thickness of 80 nm.

(Light-emitting layer deposition)
As the light emitting layer, a light emitting layer forming coating solution having the same composition as the first color light emitting layer forming coating solution used in Example 1 was applied on the hole injection layer by a spin coater, and the coating was performed at 130 ° C. for 10 minutes. An intermediate heating / drying treatment was performed to obtain a light emitting layer having a thickness of 80 nm.

(Deposition of conductive protective layer)
A Ca: Ag mixed film (10 nm) / Ag (40 nm) was formed on the light-emitting layer by a vacuum deposition method.

(Deposition of photoresist layer)
A positive photoresist solution (OFPR-800, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is dropped on the conductive protective layer, applied by a spin coater, and further prebaked at 110 ° C. for 5 minutes, with a film thickness of about 1.5 μm. A photoresist layer was obtained.

(Organic EL layer patterning)
Then, it installed in the alignment exposure machine with the exposure mask, and irradiated the ultraviolet-ray to the part which wants to remove a light emitting layer. The resist was developed with a resist developer (NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) and then washed with water to remove the photoresist in the exposed area. Post-baked at 110 ° C. for 5 minutes, the conductive protective layer where the photoresist layer has been removed is removed by plasma etching using argon gas, and the hole injection layer and light emitting layer are further removed by reactive ion etching using oxygen plasma. Was removed.

(Photoresist peeling)
The substrate was washed with acetone, the photoresist layer was removed, and a patterned organic EL layer was obtained. Then, it was dried at 130 ° C. for 1 hour.

(Formation of second electrode)
Further, on the obtained substrate, Ca was formed as a second electrode layer by 10 nm and Ag as a protective electrode was formed by a 300 nm mask vacuum vapor deposition method to produce an organic EL element.

[Comparative Example 1]
In Example 3 above, a normal organic layer in which the organic EL layer is not patterned is exactly the same except that the conductive protective layer is formed, the photoresist layer is formed, the organic EL layer is patterned, and the photoresist is not peeled off. An EL element was produced.

[Comparative Example 2]
In Example 3 above, an organic EL element was produced in exactly the same manner except that no conductive protective layer was formed.

[Evaluation]
As a performance comparison between Example 3 and Comparative Examples 1 and 2, the relative efficiency and luminance half time at a certain luminance when the value of Comparative Example 1 is set to 100 are shown in the table.

  From this result, in particular, regarding the lifetime, Comparative Example 2 which is an element of a conventional manufacturing method by photolithography and Comparative Example 1 which is a conventional element in which the organic EL layer is not patterned, and the manufacturing method according to the present invention In comparison with Example 3 which is the element of Example 3, it was found that Example 3 was superior in lifetime characteristics and was greatly improved by the insertion of the conductive protective layer according to the present invention. In addition, an extreme reduction in efficiency did not occur.

[Example 4]
An organic EL element for simply evaluating the performance of the organic EL element of Example 2 was produced.
In the formation of the conductive protective layer, Example 3 was carried out except that lithium fluoride was formed into a film with a thickness of 3 nm by a vacuum evaporation method, and Ca (10 nm) / Ag (300 nm) was formed as a second electrode by a vacuum evaporation method. In the same manner, an organic EL device was produced.

[Comparative Example 3]
In Example 4 above, a normal organic layer in which the organic EL layer is not patterned is exactly the same except that the conductive protective layer is formed, the photoresist layer is formed, the organic EL layer is patterned, and the photoresist is not peeled off. An EL element was produced.

[Comparative Example 4]
In Example 4 above, an organic EL element was produced in exactly the same manner except that no conductive protective layer was formed.

[Evaluation]
As a performance comparison between Example 4 and Comparative Examples 3 and 4, the table shows the relative efficiency and luminance half time at a certain luminance when the value of Comparative Example 3 is 100.

  From this result, in particular, regarding the lifetime, Comparative Example 4 which is an element of a conventional photolithography manufacturing method compared to Comparative Example 3 which is a normal element in which the organic EL layer is not patterned, and the manufacturing method according to the present invention. When Example 4 which is an element was compared, it was found that Example 4 exhibited superior lifetime characteristics and was greatly improved by the insertion of a conductive protective layer according to the present invention. In addition, an extreme reduction in efficiency did not occur.

It is process drawing which shows an example of the manufacturing method of the organic EL element of this invention. It is process drawing which shows the other example of the manufacturing method of the organic EL element of this invention. It is process drawing which shows the other example of the manufacturing method of the organic EL element of this invention. It is process drawing which shows the other example of the manufacturing method of the organic EL element of this invention. It is a schematic sectional drawing which shows an example of the organic EL element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 21 ... Substrate 2, 22 ... 1st electrode layer 3, 23 ... Insulating layer 4, 4 ', 24 ... Hole injection layer 5, 5', 25 ... Light emitting layer 6, 26 ... Organic EL layer 7, 7 ' , 27 ... Conductive protective layer 8, 8 '... Photoresist layer 9, 29 ... Second electrode layer 10 ... Light emitting region 20 ... Organic EL element

Claims (12)

An organic electroluminescence layer forming step of forming an organic electroluminescence layer including at least a light emitting layer on the substrate on which the first electrode layer is formed;
A conductive protective layer forming step of forming a conductive protective layer containing an inorganic conductive material on the organic electroluminescence layer;
A photoresist layer forming step of applying a photoresist on the conductive protective layer to form a photoresist layer;
A photoresist layer patterning step of patterning the photoresist layer by pattern exposing and developing the photoresist layer; and
An organic electroluminescent layer patterning step of patterning the conductive protective layer and the organic electroluminescent layer by removing the conductive protective layer and the organic electroluminescent layer in a portion where the photoresist layer is removed;
A peeling step of peeling off the remaining photoresist layer;
And a second electrode layer forming step of forming a second electrode layer on the conductive protective layer exposed after the peeling step. An organic electroluminescent element manufacturing method for forming a light emitting layer of N color (N is an integer of 2 or more) in a pattern,
From the first-color organic electroluminescence layer including at least the first-color light-emitting layer to the (N-1) -th color organic electroluminescence layer including at least the (N-1) -color light-emitting layer. Are formed in a pattern, and include at least an Nth color light emitting layer on a substrate in which a conductive protective layer and a photoresist layer each containing an inorganic conductive material are stacked in this order on the surface of each organic electroluminescent layer. An organic electroluminescence layer forming step of forming an Nth organic electroluminescence layer;
A conductive protective layer forming step of forming an Nth color conductive protective layer containing an inorganic conductive material on the organic electroluminescent layer of the Nth color;
A photoresist layer forming step of applying a photoresist on the Nth color conductive protective layer to form an Nth color photoresist layer;
A photoresist for patterning the Nth color photoresist layer so that the Nth color photoresist layer remains in the Nth color light emitting region by pattern exposure and development of the Nth color photoresist layer. A layer patterning step;
The Nth color conductive protective layer and the Nth color conductive protective layer are removed by removing the Nth color conductive protective layer and the Nth color organic electroluminescent layer in the portion where the Nth color photoresist layer is removed. An organic electroluminescence layer patterning step of patterning a colored organic electroluminescence layer;
A peeling step of peeling off each of the remaining photoresist layers;
And a second electrode layer forming step of forming a second electrode layer on each of the conductive protective layers exposed after the peeling step.   3. The method of manufacturing an organic electroluminescence element according to claim 2, wherein the N-color light-emitting layer is a three-color light-emitting layer.   The method for manufacturing an organic electroluminescence element according to any one of claims 1 to 3, wherein each of the conductive protective layers is formed by a vacuum deposition method in each of the conductive protective layer forming steps.   5. The method of manufacturing an organic electroluminescent element according to claim 1, wherein, in the second electrode layer forming step, the second electrode layer is formed by a sputtering method.   Each organic electroluminescence layer forming step is a step of forming two or more organic layers including each light emitting layer, and applying a lower layer forming coating liquid to form a lower organic layer And an upper layer forming step of forming an upper organic layer by applying an upper layer forming coating liquid on the lower organic layer, wherein the lower organic layer is the upper layer forming coating. The method for producing an organic electroluminescent element according to claim 1, wherein the organic electroluminescent element is insoluble in a solvent contained in the liquid.   The lower layer forming coating solution contains a curable binder, and the coating film obtained by applying the lower layer forming coating solution is subjected to a curing process in the lower layer forming step. Item 7. A method for producing an organic electroluminescent element according to Item 6.   The lower layer forming coating solution contains a material whose solubility is changed by the action of thermal energy or radiation, and a coating film obtained by applying the lower layer forming coating solution in the lower layer forming step The manufacturing method of the organic electroluminescent element according to claim 6, wherein the solubility of the coating film is changed by applying thermal energy to the film or irradiating with radiation.   2. The conductive protection layer and the organic electroluminescence layer in a portion where the photoresist layer has been removed are removed by dry etching in the organic electroluminescence layer patterning step. The manufacturing method of the organic electroluminescent element in any one of Claim 8.   A substrate, a first electrode layer formed on the substrate, an organic electroluminescent layer formed in a pattern on the first electrode layer and including at least a light emitting layer, and a pattern on the organic electroluminescent layer A conductive protective layer formed and containing an inorganic conductive material; and a second electrode layer formed on the conductive protective layer; and a pattern shape of the organic electroluminescent layer; and An organic electroluminescence device having the same pattern shape.   The organic electroluminescence layer has two or more organic layers including the light emitting layer, and of the two adjacent organic layers, the lower organic layer contains a curable binder. The organic electroluminescent element according to claim 10.   The organic electroluminescence layer has two or more organic layers including the light emitting layer, and the lower organic layer of the two adjacent organic layers is soluble by the action of thermal energy or radiation. The organic electroluminescent device according to claim 10, comprising a material that changes.

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