JPH10172761A - Organic electroluminescent element, manufacture thereof, organic electroluminescent display device, and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve display quantity and reliability of an organic electroluminescent(EL) display device by preventing dissipation that is likely to occur at stepped parts of a first electrode formed on the substrate side of an organic EL display device and increasing an effective luminous area. SOLUTION: After an ITO film 11 that is a first electrode is formed on a glass substrate 10, a flattened level film 12 is formed and patterned, and a flattened level film 12a is formed. Further, an ITO film 11 is over-etched, an ITO film 11a is formed, and an undercut part 15 is generated. A flattened film 14 that is an insulating film is applied to a full face and formed, a majority of the flattened film 14 and a flattened level film 12a are removed, and thereby an insulating film 14a formed at the undercut part 15 is left with a same film thickness as the ITO film 11a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device used as a light source of a display device and the like, a method of manufacturing the same, and an organic electroluminescent display device using the organic electroluminescent device and a method of manufacturing the same.

[0002]

2. Description of the Related Art Organic electroluminescence (hereinafter, referred to as organic electroluminescence)
An organic EL display device using an element (referred to as an organic EL device) has the following advantages as compared with a liquid crystal display device which is a currently mainstream flat panel display in the field of display devices.

(1) Since the organic EL element emits light, it has a wide viewing angle.

(2) A thin display device having a thickness of about 2 to 3 mm can be easily manufactured.

(3) Since it is not necessary to use a polarizing plate, a natural light emission color can be obtained.

(4) Since the dynamic range of light and dark is wide, clearer display is possible.

(5) The organic EL element can be operated in a wide temperature range.

(6) Since the response speed of the organic EL device is three orders of magnitude or more faster than that of the liquid crystal device, a moving image can be easily displayed.

Although the organic EL element has such excellent characteristics, a problem has been pointed out with respect to long-term reliability. In particular, when a point that does not emit light (so-called dark spot) occurs on the light emitting display surface of the organic EL element,
It is known that the luminance is reduced and the display quality is degraded. This dark spot is caused by a particle portion existing on an electrode (a transparent conductive film such as an ITO (Indium Tin Oxide) film in many cases, hereinafter referred to as a first electrode) formed on the substrate side or a first electrode. It is likely to occur from a portion where the coverage of the organic film formed on the step portion of the electrode is poor.

At the step portion of the first electrode, electric field concentration is likely to occur, and the organic film itself is also likely to be thinner. Very strong emission has been observed. It is also a phenomenon that a dark spot is easily generated in the step portion of the first electrode and a short circuit between the electrodes occurs with time.

Since this phenomenon occurs due to a structural problem of the organic EL element, a method of covering the step portion of the first electrode with an insulating film has been disclosed in Japanese Patent Application Laid-Open Nos.
274694 and JP-A-4-51494. Typically, the following method is employed.

That is, after forming an ITO film, which is a transparent conductive film, as a first electrode on a substrate by a sputtering method or the like, the ITO film is patterned into a predetermined shape by photolithography. Next, an insulating film such as SiO ₂ is formed over the entire surface of the substrate, and a portion where light emission is desired is exposed by photolithography, and then an organic film including a light emitting layer is formed. Further, as an electrode formed on the organic layer opposite to the first electrode, for example, a metal film containing Mg as a main component is formed. The organic EL device thus formed has a structure as shown in FIG.

[0013]

However, the above method has the following problems. That is, as is clear from FIG. 1, the ITO film (first electrode) 2 formed on the substrate 1
When the insulating film 3 covering the stepped portion is patterned by photolithography, it is necessary to set an alignment margin for photolithography, so that the insulating film 3 to be covered is also formed on the ITO film 2. become. However, the portion of the insulating film 3 does not contribute to light emission, and as a result, the area of a portion that actually emits light (hereinafter, referred to as an effective light emitting area) is smaller than the area of the ITO film 2. When manufacturing a product using a large glass substrate having at least one side of 300 mm class or more,
The alignment margin required when using a high-throughput, low-cost, one-shot exposure type exposure apparatus is usually 5
μm or more. Therefore, particularly when manufacturing a high-definition and small display device capable of displaying television images and the like,
10% reduction in display area due to this alignment margin
That's all.

Since the insulating film 3 itself has a stepped portion, the organic layer 4 and the metal electrode 5 formed over the stepped portion, or a protective film (not shown) formed after these forming steps. ) Tends to cause stress, and this stress causes film peeling or the like in the light emitting region (the portion including the organic layer 4 directly in contact with the ITO film 2 and the metal electrode 5 thereon). It has been observed through experiments by the inventor that the probability of occurrence of a non-light-emitting region such as a dark spot is thereby increased.

It is clearly desirable to obtain a large effective light emitting area, since a larger effective light emitting area improves display quality. Further, in the case where an organic EL device having such a large effective light emitting area is intended to obtain the same light emitting amount as that of an organic EL device having a small effective emitting area, the voltage supplied to the organic EL device can be lowered. The effect of extending the life of the EL element is obtained.

As described above, the conventional method described above essentially has a problem in manufacturing a display device having high reliability and capable of high-luminance display.

A method of reducing the step by forming a thin film has already been studied in an ultra LSI (Large Scale Integrated) semiconductor manufacturing process represented by a large capacity DRAM (Dynamic Random Access Memory). This is a super fine L
This is necessarily required from the structure specific to SI. In the VLSI, there is a portion where the step and the pattern width of the thin film are almost the same size or the step is larger than the pattern width as the pattern becomes finer. Unless such steps are not filled with an insulating film,
It is known that a defect such as disconnection occurs in a wiring formed on a step portion. As a technique for eliminating such a step, for example, CVD (Ch
After forming a thin film mainly composed of SiO ₂ as an insulating film by an emical vapor deposition (SOG) method or a spin-on-glass (SOG) method, chemical mechanical polishing (CMP, Chemo-
A method of performing mechanical polishing or a method of performing etch back by dry etching is often used.

However, when these methods are applied to a manufacturing process of an organic EL display device so as to eliminate a step in the first electrode, the following problem occurs. That is, in the method of performing the chemical mechanical polishing, the surface of the first electrode may be finely scratched. If the surface of the first electrode has a flaw, the flaw may shorten the light emission life of the organic EL element or generate a dark spot. On the other hand, in the method of etching back by dry etching, since it is difficult to perform uniform etching, a region where the corner of the step of the first electrode is exposed is generated. In addition, it is apparent that the variation in the thickness of the insulating film at the time of forming the insulating film to be etched back is superimposed on the variation in the etching.

From the above, it can be seen that there is a problem in applying the method used in the VLSI semiconductor manufacturing process as it is, or it is insufficient to apply it as it is.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for forming a first organic EL display device on a substrate side using a method different from the above-described conventional method.
It is an object of the present invention to improve the display quality and reliability of the organic EL display device by preventing the occurrence of a defect which is likely to occur at the step portion of the electrode and further increasing the effective light emitting area.

[0021]

In order to solve the above-mentioned problems, an organic electroluminescence device according to the present invention comprises an insulating film on a side of a transparent electrode formed between a light emitting layer and a light-transmitting substrate. Is formed, and the insulating film has the same thickness as the electrode.

Further, the organic electroluminescence element of the present invention comprises a substrate having a light-transmitting property, a transparent electrode formed on the substrate, and a film having the same thickness as the transparent electrode formed on the side of the transparent electrode. And a light emitting layer formed on the transparent electrode.

In the method of manufacturing an organic electroluminescence device according to the present invention, a transparent electrode is formed on a light-transmitting substrate, and an etching-resistant film having resistance to an etching material for the transparent electrode is formed on the transparent electrode. Formed on, overetching the transparent electrode so that this etching-resistant film overhangs the transparent electrode, forming an insulating film also on the portion where the transparent electrode is overetched by applying an insulating film, The insulating film and the etching resistant film are removed so that only the insulating film formed on the side of the transparent electrode remains.

Further, in the method of manufacturing an organic electroluminescence device according to the present invention, an electrode is formed on a light-transmitting substrate, and a flattening level film is formed on the electrode. The electrode is over-etched so as to overhang the electrode, heat treatment is performed so as to bend the overhang portion of the planarization level film in a direction away from the substrate, and after the heat treatment, a flattening film is applied to form the electrode. A flattening film is also formed on the overetched portion, and the flattening film and the flattening level film are removed so that only the flattening film formed on the side of the electrode remains. .

In the organic electroluminescent display device according to the present invention, an insulating film is formed in contact with the side surface of the electrode located on the substrate side, which is more transparent than the film having the light emitting function.
The insulating film has the same thickness as the electrode.

Further, the organic electroluminescence display device of the present invention comprises a light-transmitting substrate, a color filter formed on the substrate, a first electrode formed on the color filter, and a first electrode. An insulating film formed on a side portion of the first electrode and having the same thickness as the first electrode; a light emitting layer formed on the first electrode; and a light emitting layer formed on the light emitting layer so as to face the first electrode. And a second electrode.

According to the method of manufacturing an organic electroluminescent display device of the present invention, an electrode is formed on a substrate, a flattening level film is formed on the electrode, and the flattening level film overhangs the electrode. The electrode is over-etched, a flattening film is applied, and a flattening film is formed also in a portion where the electrode is over-etched, and only the flattening film formed on the side of the electrode remains. And removing the planarization film and the planarization level film.

Further, according to the method of manufacturing an organic electroluminescence display device of the present invention, a color filter is formed on a light-transmitting substrate, a first electrode is formed on the color filter, and a first electrode is formed. An insulating film having the same thickness as the first electrode is formed on a side portion, a light-emitting layer is formed over the first electrode, and a second electrode is formed over the light-emitting layer so as to face the first electrode. It is characterized by doing.

[0029]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[Embodiment 1] The essence of the problem in the conventional method is that there is a step in the first electrode. Therefore, the first of the organic electroluminescence (EL) elements
The electrode may be flattened to eliminate the step. In a structure in which the first electrode is flattened and has no step, an insulating film having the same thickness as the first electrode is formed by the first electrode.
By forming it on the side of the electrode pattern. Hereinafter, such a structure is referred to as a step flattened structure.

The step flattening structure of the first electrode can be obtained by the following manufacturing method. Here, a case of an organic EL display device using an organic EL element using an ITO (Indium Tin Oxide) film as the first electrode will be described. However, the first electrode is not limited to the ITO film. It is also possible to use a SnO ₂ film or a ZnO film as the first electrode.

(1) An ITO film 11 is formed on a light-transmitting substrate 10 such as a glass substrate by using an appropriate method such as a sputtering method or an evaporation method (see FIG. 2A).

(2) After the ITO film 11 is formed, an etchant used for etching the ITO film 11 in a later step (an etchant for wet etching, an etching gas for dry etching)
At least one thin film or resin (hereinafter, referred to as a planarization level film 12) which is hardly etched by being etched is formed (see FIG. 2B).

(3) A photosensitive resin 13 such as a photoresist is selectively applied on the flattening level film 12, and the flattening level film 12 is patterned into a desired shape using the applied photosensitive resin 13. Thereby, a flattening level film 12a is formed (see FIG. 2C).

(4) After forming the planarization level film 12a,
By over-etching the ITO film 11, I
A TO film 11a is formed, and a sufficient undercut portion 15 is formed below the planarization level film 12a. This undercut portion 15 has a predetermined undercut length 16. After that, the photosensitive resin 13 used for patterning the flattening level film 12 is removed (see FIG. 2D).

(5) After removing the photosensitive resin 13, an insulating film (hereinafter, referred to as a flattening film) 14 that can be formed by a coating method such as a resin or an SOG (spin-on-glass) film is formed (see FIG. 4). (See FIG. 2E). In the coating method, the coating material (insulator) can be impregnated into any gaps, so that the undercut portion 15 is also filled with the insulating film.

If the photosensitive resin 13 does not dissolve in the solvent of the flattening film 14, the photosensitive resin 13 may be removed after forming the flattening film 14 (in this case, the photosensitive resin 13 is further removed). It is necessary that the planarizing film 14 is not attacked by the stripping solution.) Note that the ITO film 1 is used as the planarization level film 12.
Since an etching-resistant material that can withstand the etchant used for etching 1 is used, the photosensitive resin 13 may be removed before etching the ITO film 11.

(6) After forming the planarizing film 14 as shown in FIG. 2E, the insulating film (insulating material) is removed by removing most of the planarizing film including the insulating film on the planarizing level film 12a. )
14a is formed (see FIG. 2F). Further, when the flattening level film 12a is removed, the insulating film 14a formed in the undercut portion 15 remains with the same thickness as the ITO film 11a (see FIG. 2G).

The flattening film 14 can be removed by using a method of etching back by dry etching. When the flattening film 14 is removed by wet etching,
The undercut length is made sufficiently longer than the thickness of the insulating film 14a, and is sufficient for etching in the thickness direction of the insulating film 14a (direction perpendicular to the substrate 10), but is sufficient in the length direction of the undercut (substrate 10). The etching may be performed only for a time that is insufficient for the etching to proceed in the direction parallel to the direction of the etching.

If a positive photosensitive resin is used as the flattening film 20 and a thin film that blocks at least light having a wavelength sensitive to the positive photosensitive resin is used as the flattening level film 21, the positive photosensitive resin can be used. By exposing and developing after the application (see FIG. 3A), the positive photosensitive resin is removed, and only the undercut portion hidden by the flattening level film 21 is the unexposed positive photosensitive resin. The insulating film (insulator) 20a can be left (see FIG. 3B). After that, the planarization level film 21 may be removed (see FIG. 3C).

If a negative photosensitive resin is used as the flattening film 22 and a thin film that blocks at least light having a wavelength sensitive to the negative photosensitive resin is used as the flattening level film 23, the negative photosensitive resin may be used. Is applied to the substrate 10 having a light-transmitting property and exposed to light from the side of the substrate 10 (see FIG. 4A), whereby the negative photosensitive resin formed on the flattening level film 23 is removed during development (FIG. 4 (b)). afterwards,
What is necessary is just to remove the planarization level film 23 (see FIG. 4C). Thereby, an insulating film (insulator) 22a can be formed.

After the removal of the leveling level film 23, the insulating film 22a having irregularities on the surface actually remains, but the degree of the irregularities is the same as that of the conventional organic EL device. The thickness of the electrode is sufficiently smaller than the film thickness of the stepped portion, and the presence of the unevenness can be ignored in the present invention. Therefore, the unevenness is not shown in FIG.

As described above, if the unnecessary leveling film not in contact with the side wall of the ITO film is removed and then the leveling level film is further removed, the step flattening structure according to the present invention can be obtained.

Further, the flattening level film 25 is formed of an ITO film 26.
And the thickness of the planarizing film 24 is smaller than the thickness of the ITO film 26 plus the thickness of the planarizing level film 25 (see FIG. 5A). Then, when the planarization level film 25 is removed, the planarization level film 25 is removed.
The flattening film 24 formed on, for example, is also removed simultaneously by the lift-off method (see FIG. 5B). This allows
An insulating film 24a can be formed.

After the planarization level film 25 and the planarization film 24 are simultaneously removed by the lift-off method, the insulating film 24a having irregularities on the surface actually remains. The size of the unevenness is sufficiently smaller than the thickness of the step portion in the first electrode of the conventional organic EL element, and the present invention can ignore the presence of the unevenness. Therefore, the unevenness is not shown in FIG.

As described above, the first electrode (ITO) which is flattened at the end of the pattern and has no level difference
An organic EL display device using the organic EL element according to the present invention is manufactured by forming an organic film including a light emitting layer on the film) and further forming a second electrode on the organic film.

Here, a production example of an organic EL display device using the organic EL element according to the present invention will be described more specifically. That is, using a novolak resin-based positive resist as the flattening film, the pixel size is 0.30 mm × 0.
An example of manufacturing a dot matrix type organic EL display device having 256 × 128 dots composed of 30 mm dots will be described below.

First, an inexpensive soda glass substrate is selected as a substrate used for forming an organic EL display device, and the entire surface of the glass substrate is coated with silica. This silica coating has the effect of suppressing the elution of sodium from the glass substrate when the glass substrate is heated, protecting the soda glass substrate that is vulnerable to acids and alkalis, and improving the flatness of the surface of the glass substrate. To get it.

Next, an ITO film, which is a transparent conductive film, was formed as a first electrode on a glass substrate by a sputtering method.
000 angstroms is formed. The ITO film is used because the properties as a transparent conductive film are better than other materials. However, a transparent conductive film such as a ZnO film or a SnO ₂ film can also be used if its transmittance and resistivity do not cause any problem in use. When a film is formed over a large area, the sputtering method is particularly excellent in terms of uniformity, and is also excellent in film quality and productivity. However, the method for forming the ITO film is not limited to the sputtering method. For example, the ITO film may be formed by a vapor deposition method.

After the ITO film is formed, a TiN (titanium nitride) film is formed as a flattening level film to a thickness of 500 Å. Further, after forming a resist pattern on the TiN film by photolithography, a TiN film is formed using a commercially available etching solution (hereinafter, referred to as ammonia peroxide) in which ammonia and hydrogen peroxide are mixed at a volume ratio of 1:16. Is removed by etching, and the ITO film is further etched with a hydrochloric acid-based etchant.

The ITO film used here was etched for one minute and three minutes to remove it by etching to a thickness of 1000 angstroms.
The film is formed by setting the film forming conditions such that the film quality requires about 0 seconds. The etching of the ITO film is performed for a total of 10 minutes including over-etching.
An undercut portion is obtained below the pattern of the N film.
The undercut length of this undercut part is about 600
0 Angstrom.

After drying the glass substrate, the resist is peeled off.

Here, the TiN film is used as the flattening level film, but has a light-shielding property and is hardly etched by the etching solution for the ITO film.
It is apparent that the present invention is not limited to the TiN film as long as the thin film does not attack the O film. For example, a film containing Cr as a main component or a film containing Ti as a main component can be used as such a film.

Subsequently, a positive resist was applied as a flattening film over the entire surface to form a film, and further subjected to a pre-bake at 120 ° C. for 90 seconds, followed by a 10 mW / cm ² exposure intensity of 10 mW / cm ^2.
Exposure for 2. seconds and 2.38% TMAH (tetramethy
Development is performed using an aqueous solution of ammoniumhydroxide. Further, after washing with pure water, drying is performed, post-baking is performed for 3 minutes on a hot plate heated to 150 ° C., and after sufficiently hardening, the TiN film is removed using ammonia peroxide. .

It should be noted that, in FIG.
Since the insulating film 51 such as a positive resist remaining on the side of the ITO film 50 on the upper side 2 slightly shrinks, the film thickness of the portion 51a far from the side surface of the ITO film 50 becomes thin.
The portion 51b in contact with the side surface of the O film 50 is the ITO film 50
And the film thickness becomes almost the same.

In FIG. 14, the tensile stress of the TiN film 61 formed on the ITO film 62 is increased by heating the substrate 60 to about 100 ° C. before forming the flattening film. For example, the overhang portion of the TiN film 61 on the undercut portion is slightly turned up, and curves in a direction away from the substrate 60. Therefore, after such a heat treatment, a flattening film is formed and the ITO film 6 is formed.
If the step of forming the insulating film 63 on the side surface of the substrate 2 is performed, ITO
The decrease in the thickness of the insulating film 63 at a portion away from the side surface of the film 62 is smaller than that of the insulating film 51 shown in FIG.

As described above, the step flattening structure according to the present invention in which the insulating film having the same thickness as the first electrode is formed on the side of the first electrode.

Next, as the hole injection layer and the hole transport layer in the organic EL device including the light emitting layer, N, N'-bis (m
-Methylphenyl) -N, N'-diphenyl-1,1 '
-Biphenyl-4,4'-diamine (N, N'-bis (m-methy
l phenyl) -N, N'-diphenyl-1,1'-biphenyl-4,4'-diamin
e, hereinafter referred to as TPD. 6) was used as a light emitting layer and an electron transporting layer, and tris (8-hydroxyquinoline) aluminum (hereinafter A)
It referred to as the lq _3. 7) was replaced by Mg /
An Ag alloy (weight ratio 10: 1) film is continuously deposited without exposing to air in a vacuum. The thickness of each film is 500 angstroms.

The present invention relates to the organic E used in the first embodiment.
It is not limited to the constituent films of the L element and the stacking order thereof. Further, another material may be used for the hole injection layer, the light emitting layer, and the second electrode, and a hole injection layer, an electron transport layer, an electron injection layer, and the like may be further formed to have a multilayer structure. That is, the present invention is applicable irrespective of the type and structure of the material to be formed.

Subsequently, an Al film is formed to a thickness of 2,000 angstroms by a sputtering method without being exposed to the air in a vacuum.

In order to form a pattern of the Al film and the Mg / Ag film, dry etching is performed after forming a resist pattern using a rubber-based negative resist. This dry etching is performed by a RIE (Reactive Ion Etching) method with an input power of 2000 W and a gas pressure of 100 mTorr.
Do with. Cl ₂ and BCl ₃ are used as an etching gas.

After this dry etching, an ashing process is performed in a vacuum without exposing it to the atmosphere. This occurs after dry etching called after-corrosion.
This is to prevent the corrosion of l. Note that the resist pattern is also removed during the ashing process.

Further, an SiO ₂ film is formed as a protective film by a sputtering method, whereby an organic EL device is completed. It has been confirmed that in the organic EL display device using the organic EL element thus obtained, no dark spot is generated or progresses from the end of the pattern of the ITO film, and thus high reliability can be obtained. .

[Embodiment 2] The dot size is 50 μm in width.
m, height 150 μm, and the number of dots is 256 × 3 (RG
B) An example of manufacturing a simple matrix type organic EL display device having 192 dots will be described below. In the second embodiment, multi-color light emission is enabled by forming a color filter as compared with the first embodiment, and the light emission is further reduced. Note that the size of the glass substrate used for manufacturing is 3
It is 00 × 400 mm and can take 64 display panels.

First, Corning # 70 manufactured by Corning Incorporated
59 glass is used as the substrate 30, and a coating process of a pigment dispersion type color filter which is the most common as a coloring method is performed on the substrate 30. After that, patterning is performed by selecting film forming conditions such that each filter of each color of RGB (red, green, blue) has a film thickness of 1.5 to 2.2 μm.

For example, the step of forming and applying a red color filter is performed as follows. After spin coating the red color filter solution at 1000 rpm (rotation / minute) for 5 seconds, prebaking is performed on a hot plate at 100 ° C. for 3 minutes. Further, after aligning the photomask with an exposure machine and irradiating with ultraviolet light of 20 mW / cm ² for 30 seconds, development is performed using a TMAH aqueous solution having a concentration of about 0.1%. The development time is about 1 minute. Further, curing (thermal curing) is performed at 220 ° C. for 30 minutes so as not to dissolve in a color filter liquid of another color (green or blue) applied in a later step, thereby forming a red color filter (pattern) 31. (See FIG. 8A).

Color filter 3 of another color (green or blue)
Regarding 2 and 33, since the material (pigment) is different, the conditions for forming the red color filter 31 are different in detail, but substantially the same steps may be sequentially performed (FIG. 8).
(B)). Here, an example using only a color filter is described because manufacture is relatively easy. But,
For example, green or red may be output by performing color conversion using a fluorescence conversion filter so as to emit light with higher luminance. Further, by stacking a color filter and a fluorescence conversion filter, it is also possible to prevent both a decrease in luminance and an improvement in color purity.

Next, an overcoat material 34 is applied on the color filters 31, 32, 33 to improve the flatness of the surface on which an ITO film to be formed in a later step is formed. Cure at 30 ° C. for 30 minutes (see FIG. 8C).

Subsequently, an ITO film 35 as a transparent conductive film is formed as a first electrode by 1000 Å by sputtering, and then a TiN (titanium nitride) film 36 is formed as a flattening level film by 500 Å (FIG. 8 (d)).

Further, TiN is formed by photolithography.
After selectively forming a resist pattern on the film 36,
The exposed portion of the TiN film 36 is removed by etching using the above-described ammonia peroxide, and the ITO film 35 is further etched with a hydrochloric acid-based etchant. IT used here
It takes 1 minute and 40 seconds to etch and remove the 1000 angstrom thickness of the O film 35. However, by performing the etching for 10 minutes, the undercut having a length of about 6000 angstrom under the pattern of the TiN film 36a is obtained. A portion and an ITO film 35a are obtained. After that, the resist is peeled off after the substrate 30 is dried (see FIG. 8E).

Subsequently, a positive photosensitive polyimide is applied as a flattening film 37 to form a film (see FIG. 8F).
After pre-baking at 20 ° C. for 20 minutes and exposure with ultraviolet light having an exposure intensity of 10 mW / cm ² for 180 seconds, TMA
Development is performed using an H aqueous solution (FIG. 8 (g)).

After washing and drying with pure water, complete curing is performed by using an oven at 150 ° C. for 1 hour and at 350 ° C. for 30 minutes, and the TiN film 36a is removed with ammonia peroxide. At the time of curing, the photosensitive polyimide shrinks by about 20%, but the flattening film 37a in contact with the ITO film 35a has the same thickness as the ITO film 35a.

As described above, the step portion is largely eliminated, and a flattened ITO film (first electrode) is formed (see FIG. 8H).

The organic layer and the second electrode formed on the ITO film are formed by forming the following materials. In the second embodiment, an organic EL material that emits white light is used.

As the hole injection layer, poly (thiophene-2,
5-diyl) (see FIG. 9) was deposited to a thickness of 100 Å, and TPD was used as a hole transport layer and a yellow light emitting layer.
(See FIG. 6) Doubly doped with rubrene (see FIG. 10) at a ratio of 1% by weight is formed into a 500 Å film by a co-evaporation method. The concentration of rubrene is preferably about 0.1 to 10% by weight, and light is emitted with high efficiency in this concentration range. Note that the concentration may be determined by the color balance of the emission color, but is determined by the light intensity and the wavelength spectrum of the blue emission layer to be formed later. In addition, 4, 4
', -Bis [(1,1,2-triphenyl) ethenyl]
500 Å of biphenyl (see FIG. 11),
100 Å of Alq ₃ as an electron transport layer,
As a second electrode, an Mg / Ag alloy (weight ratio: 10: 1) film is continuously deposited in a vacuum of 2000 Å without being exposed to the atmosphere. As described above,
As shown in FIG. 12, an organic layer 40 is formed.

Subsequently, similarly, an Al film 41 and a SiO ₂ film 42 are formed by a sputtering method without being exposed to the air in a vacuum. Note that the extraction electrode portion is previously covered with a metal mask or the like so that the SiO ₂ film as an insulating film is not formed on the extraction electrode portion (not shown) when the SiO ₂ film 42 is formed.

The color simple matrix type organic EL display device is manufactured as described above. The organic EL display device thus obtained has an effective light emitting area of 8
7.0%, which is 67.7% of the effective light emitting area obtained when the edge portion of the first electrode is covered with an insulating film of about 5 μm.
%, Which is significantly wider than that of the conventional organic EL display device.
A display device can be obtained.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

In the second embodiment, a simple matrix organic E
Although the L display device has been described, the present invention can also be applied to an active matrix organic EL display device. Further, the organic EL display device of the present invention can be applied to products in a field to which a liquid crystal display device can be applied. Further, for example, the organic EL element of the present invention can be applied to a head portion of a printer.

[0080]

As described in detail above, the organic EL display panel using the organic EL device according to the present invention is a conventional organic EL display panel.
As compared with the L display panel, the display area is excellent because the effective light emitting area is large, and the ITO film used as the first electrode has less steps and is more flattened. The occurrence of spots can be prevented. Therefore, a highly reliable flat panel display can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conventional organic electroluminescence (EL) element in which a step portion of an ITO film used as a first electrode is covered with an insulating film.

FIG. 2 is a view showing a step of forming a step flattened structure in the organic EL device according to the first embodiment of the present invention.

FIG. 3 is a view showing a step of forming a step flattening structure in the organic EL element according to the first embodiment of the present invention using a positive photosensitive resin.

FIG. 4 is a view showing a step of forming a step flattening structure in the organic EL element according to the first embodiment of the present invention using a negative photosensitive resin.

FIG. 5 is a view showing a step of forming a step flattened structure in the organic EL element according to the first embodiment of the present invention by a lift-off method.

FIG. 6 shows N, N′-bis (m-methylphenyl) -N,
N'-diphenyl-1,1'-biphenyl-4,4'-
The figure which shows the chemical structural formula of a diamine.

FIG. 7 shows a chemical structural formula of tris (8-hydroxyquinoline) aluminum.

FIG. 8 is a view showing a step of forming a step flattened structure in the organic EL element according to the second embodiment of the present invention.

FIG. 9 shows a chemical structural formula of poly (thiophene-2,5-diyl).

FIG. 10 shows a chemical structural formula of rubrene.

FIG. 11 shows a chemical structural formula of 4,4 ′,-bis [(1,1,2-triphenyl) ethenyl] biphenyl.

FIG. 12 is a sectional view of a color simple matrix type organic EL display device manufactured by a process according to a second embodiment of the present invention.

FIG. 13 is a diagram showing a state of formation of an insulating film on a side portion of the ITO film according to the first embodiment of the present invention.

FIG. 14 is a diagram showing a state of formation of an insulating film on a side portion of the ITO film according to the first embodiment of the present invention.

[Description of Signs] 1, 10, 30, 52, 60 Substrates 2, 11, 11a, 26, 35, 35a, 50, 62
ITO film 3, 14a, 20a, 22a, 24a, 63 Insulating film 4, 40 Organic layer 5 Metal electrode 12, 12a, 21, 23, 25 Flattening level film 13 Photosensitive resin 14, 24, 20, 22, 24, 37,37a planarization layer 15 undercut 16 undercut length 31, 32, 33, the color filter 34 overcoat material 36,61 TiN film 41 Al film 42 SiO ₂ film

Claims (13)

[Claims] An insulating film is formed on a side of a transparent electrode formed between a light emitting layer and a light-transmitting substrate, and the insulating film has the same thickness as the electrode. Organic electroluminescent element. 2. A transparent substrate, a transparent electrode formed on the substrate, an insulating film formed on a side of the transparent electrode and having the same thickness as the transparent electrode, and An organic electroluminescence device comprising: a light-emitting layer formed on the substrate. 3. A transparent electrode is formed on a transparent substrate, an insulating film having the same thickness as the transparent electrode is formed on a side of the transparent electrode, and a light emitting layer is formed on the transparent electrode. A method for manufacturing an organic electroluminescent element. 4. A transparent electrode is formed on a light-transmitting substrate, and an etching resistant film having resistance to an etching material for the transparent electrode is formed on the transparent electrode. The transparent electrode is over-etched so as to overhang the transparent electrode, an insulating film is applied, and an insulating film is formed also on a portion where the transparent electrode is over-etched. And removing the insulating film and the etching resistant film so that only the insulating film remains. 5. An electrode is formed on a light-transmitting substrate, a flattening level film is formed on the electrode, and the electrode is over-etched so that the flattening level film overhangs the electrode. Then, a heat treatment is performed to bend the overhang portion of the planarization level film in a direction away from the substrate. After the heat treatment, the planarization film is applied, and the planarization film is also applied to a portion where the electrode is over-etched. Forming a planarizing film and a planarizing level film such that only a planarizing film formed on a side portion of the electrode remains. 6. The method according to claim 4, wherein the flattening film remaining on the side of the electrode has the same thickness as the electrode. 7. An insulating film is formed in contact with a side surface of an electrode located on a substrate side having a property of transmitting light more than a film having a light emitting function, and the insulating film has the same thickness as the electrode. Organic electroluminescence display device. 8. A substrate having a light-transmitting property, an electrode formed on the substrate, an insulating film formed on a side portion of the electrode and having the same thickness as the electrode, and formed on the electrode. An organic electroluminescence display device comprising a light-emitting layer. 9. A light-transmitting substrate, a color filter formed on the substrate, a first electrode formed on the color filter, and a first electrode formed on a side of the first electrode. An insulating film having the same thickness as the first electrode, a light emitting layer formed on the first electrode, and a second electrode formed on the light emitting layer so as to face the first electrode. Characteristic organic electroluminescent display device. 10. An electrode is formed on a substrate, a flattening level film is formed on the electrode, and the electrode is over-etched so that the flattening level film overhangs the electrode. A flattening film is formed by applying a passivation film to a portion where the electrode is over-etched. A method for manufacturing an organic electroluminescent display device, comprising: 11. The flattening film remaining on the side of the electrode has the same thickness as the electrode.
0. The method for manufacturing an organic electroluminescent display device according to item 0. 12. An electrode is formed over a light-transmitting substrate, an insulating film having the same thickness as the electrode is formed on a side of the electrode, and a light-emitting layer is formed over the electrode. Of manufacturing an organic electroluminescent display device. 13. A color filter is formed on a light-transmitting substrate, a first electrode is formed on the color filter, and a side portion of the first electrode has the same thickness as the first electrode. A method for manufacturing an organic electroluminescent display device, comprising: forming an insulating film; forming a light emitting layer on a first electrode; and forming a second electrode on the light emitting layer so as to face the first electrode. Method.