JP3807114B2 - Method for manufacturing light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
Relates to a manufacturing method of the present invention is a light-emitting element, and more particularly to a method of manufacturing a light emitting device using an organic EL (electroluminescence) material in the light emitting layer.
[0002]
[Prior art]
Conventionally, a light emitting element using an organic EL material has a structure as shown in FIG. As shown in the figure, the light-emitting element 1 includes an organic EL layer 4 formed on a transparent front electrode 3 formed on a glass substrate 2 and a back electrode 5 formed on the organic EL layer 4. Yes. Light is emitted by applying a voltage between the front electrode 3 and the back electrode 5. The back electrode 5 is formed by vacuum vapor deposition. At this time, in order to form a desired pattern, vapor deposition is performed with a metal mask disposed on the substrate. A desired pattern is formed as an opening in the metal mask.
[0003]
When the back electrode 5 is miniaturized using this method, it is required to finely process the metal mask. However, since the strength of the metal mask cannot be maintained, a space of about 0.1 mm is a limit. Accordingly, methods as shown in FIGS. 14 to 16 have been proposed for further miniaturization. 14 is a plan view showing a state after the back electrode 5 is deposited, FIG. 15 is an XX sectional view of FIG. 14, and FIG. 16 is a YY sectional view of FIG. In this method, a photoresist 6 having a reverse taper side wall is formed between desired back electrode formation regions without using a metal mask, and then an organic EL layer 4 and a back electrode 5 are deposited as shown in FIG. It is a thing. In this method, since the organic EL layer 4 and the back electrode 5 are separated by the inversely tapered photoresist 6, the organic EL layer 4A separated on the photoresist 6 and the organic EL layer 4A are separated. Pattern formation is performed in a state where the back electrode 5A is electrically insulated from the back electrode 5, and fine pattern formation is possible.
[0004]
[Problems to be solved by the invention]
However, in the above-described method, when the back electrode 5 is formed using the photoresist 6 whose side wall is inversely tapered, the front electrode 3 and the back electrode 5 are formed in the vicinity of the lower portion of the side wall of the photoresist 6 as shown in FIG. There is a problem that a short circuit easily occurs between the two. This is because if the organic EL layer 4 is deposited near the photoresist 6 near the lower portion of the side wall of the photoresist 6 rather than the range where the back electrode 5 is deposited, a short circuit between the electrodes does not occur. Is deposited closer to the photoresist 6 than the organic EL layer 4, a short circuit between the electrodes occurs.
[0005]
The present invention is intended to provide a method for manufacturing a light emitting device capable of preventing the short circuit between the front electrode and the back electrode.
[0006]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a method for manufacturing a light emitting device in which one electrode, an electroluminescent layer formed by laminating a plurality of films, and the other electrode are formed on a substrate in order. After the formation, the electroluminescent layer is formed by forming a separation layer in which the side wall has a reverse taper shape and the edge of the upper part of the pattern is located outside the plane region corresponding to each light emitting portion of the one electrode. A predetermined film of a plurality of films is wet-formed on the entire surface of the substrate to form the electroluminescent layer, and then the material for forming the other electrode is formed using the separation layer as a mask. It is said.
[0010]
In the first aspect of the present invention, the separation layer is covered with a predetermined film by wet-depositing a predetermined organic film among the plurality of films, and the other electrode and one electrode deposited in a later step It is possible to prevent a short circuit from occurring between the two.
[0011]
According to a second aspect of the present invention, there is provided a method for manufacturing a light emitting device according to the first aspect , wherein the predetermined film is made of a material soluble in an organic solvent.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the details of the method for manufacturing a light emitting device according to the present invention will be described based on each embodiment shown in the drawings.
(Embodiment 1)
1 to 10 show Embodiment 1 of a method for manufacturing a light-emitting element according to the present invention. First, in this embodiment, as shown in FIGS. 1 and 2, a plurality of front electrodes 12 are formed in parallel on a glass substrate 11 with a predetermined interval therebetween. The front electrode 12 is made of, for example, ITO (indium tin oxide), which is a transparent conductive material. The front electrode 12 is formed by forming an ITO film on the entire surface of the glass substrate 11 and patterning it by a photolithography technique and an etching technique. 2 is a cross-sectional view taken along the line AA in FIG.
[0013]
Next, after an interlayer insulating film 13 made of SiO ₂ is deposited on the entire surface of the glass substrate 11 on which the front electrode 12 is formed, as shown in FIGS. 3 and 4, using a photolithography technique and an etching technique. Then, the pattern is formed so that the portion to be the light emitting portion becomes a rectangular opening 13A. 4 is a cross-sectional view taken along the line BB in FIG. Each of the openings 13A becomes a light emitting pixel region.
[0014]
Thereafter, a photoresist is applied to the front surface, and exposure and development are performed. As shown in FIGS. 5 and 6, the openings 13A extend in a direction perpendicular to the extending direction of the front electrode 12, and will be described later. A resist layer 14 patterned so as to expose a portion where the back electrode is to be formed is formed. As shown in FIG. 6, the resist layer 14 is formed so that the side wall has an inversely tapered shape. 6 is a cross-sectional view taken along the line CC of FIG. As shown in FIG. 6, the resist layer 14 is set to have a width shorter than the distance between adjacent openings 13A in the extending direction of the front electrode 12, and the interlayer insulating film between the adjacent openings 13A. 13 is formed so as to pass through the center.
[0015]
Next, as shown in FIGS. 7 to 9, an organic EL material layer and a back electrode material layer 16 are sequentially deposited on the entire surface. As a result, the resist layer 14 is divided by an inversely tapered step, and the organic EL layer 15 is formed on the resist layer 14, and the back electrode material layer 16 is formed on the organic EL layer 15. An organic EL layer 15A is bonded to the front electrode 12 exposed in the opening 13A of the interlayer insulating film 13, and a back electrode 16A is bonded to the organic EL layer 15A. The organic EL layer 15A in the present embodiment is formed by laminating a light emitting layer, a carrier transport layer, and the like. A plurality of back electrodes 16 </ b> A are formed in a stripe shape in a direction crossing the front electrode 12.
[0016]
Thus, in this embodiment, by forming the interlayer insulating film 13 under the resist layer 14, the back electrode 16A is closer to the resist layer 14 than the organic EL layer 15A, as shown in FIG. Even if it is vapor-deposited, the occurrence of a short circuit between the front electrode 12 and the back electrode 16A is not prevented. The organic EL layer 15 and the back electrode 16 </ b> A can be stably deposited on the interlayer insulating film 13 by forming the maximum pattern width of the reverse tapered resist narrower than the pattern width of the interlayer insulating film 13. In the present embodiment, since the light emission pattern is regulated by the interlayer insulating film 13, there is no influence on the pattern accuracy of the back electrode 16A like the light emission pattern in which the light emission pattern is regulated by a conventional reverse tapered resist layer. Therefore, a uniform light emission pattern can be obtained. In this embodiment, the interlayer insulating film 13 is formed of SiO ₂ , but an acrylic organic thin film in which the interlayer insulating film has a black mask function may be used. Furthermore, in this embodiment, after the manufacturing process, the resist layer 14 is stripped using a stripping solution to remove the organic EL layer 15 and the back electrode material layer 16 on the resist layer 14 as shown in FIG. May be.
[0017]
(Embodiment 2)
FIG. 11: is principal part sectional drawing which shows Embodiment 2 of the manufacturing method of the light emitting element which concerns on this invention. In this embodiment, without forming the interlayer insulating film 13 as in Embodiment 1 described above, a resist layer 14 having a reverse-tapered sidewall is directly formed on the front electrode 12, and then the organic EL layer 15 is formed. A first organic film 15A formed of a polymer material such as polyvinyl carbazole or polyaniline that dissolves in an organic solvent, or polyphenylene vinylene that is an organic EL precursor is wet-formed, and is formed on the entire surface electrode 12 and the resist layer. Completely cover 14 side walls and top surface. Thereafter, a second organic film 15B formed by sequentially laminating a light emitting layer and a carrier transport layer is deposited. Subsequently, a back electrode material layer 16 is deposited on the second organic film 15B. Also in the second embodiment, since the side wall of the resist layer 14 is formed in a reverse taper shape, the second organic film 15B and the back electrode material layer 16 are divided and patterned by the step of the resist layer 14, respectively. Thereafter, after the first organic film 15A exposed with the organic solvent is dissolved, the resist layer 14 may be stripped with a stripping solution to perform lift-off.
[0018]
In the second embodiment, the front electrode 12 and the resist layer 14 can be completely covered by forming the first organic film 15A by wet deposition after the resist layer 14 is formed. For this reason, even if the back electrode 16A is deposited closer to the resist layer 14 than the second organic film 15B, a short circuit between the front electrode 12 and the back electrode 16A can be prevented. In the present embodiment, even if the width of the resist layer 14 is narrowed, a short circuit can be prevented, so that the area of the light emitting portion can be set large.
[0019]
(Embodiment 3)
FIG. 12 is a cross-sectional view of a main part showing Embodiment 3 of the method for manufacturing a light emitting device according to the present invention. In the third embodiment, the interlayer insulating film 13 is formed in the same manner as in the first embodiment, and then the first organic film 15A is wet-formed in the same manner as in the second embodiment, followed by the second organic film. 15B and the back electrode material layer 16 are sequentially deposited. In the present embodiment, the width dimension of the resist layer 14 may be equal to or smaller than the width dimension of the interlayer insulating film 13. The other steps in the third embodiment are the same as those in the second embodiment.
[0020]
In the third embodiment, since the width dimension of the interlayer insulating film 13 can be set short, miniaturization can be promoted. Further, since the interlayer insulating film 13 is formed on the front electrode 12, a short circuit can be surely prevented.
[0021]
Although the embodiments have been described above, the present invention is not limited to these embodiments, and various design changes accompanying the gist of the configuration are possible.
[0022]
【The invention's effect】
As apparent from the above description, according to the present invention, it is possible to prevent a short circuit from occurring between one electrode and the other electrode sandwiching the organic EL layer of the light emitting element. Further, since the pattern of the other electrode can be formed by applying a lithography technique, miniaturization can be achieved.
[Brief description of the drawings]
FIG. 1 is a plan view showing an initial step of Embodiment 1 of a method for manufacturing a light-emitting element according to the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a plan view showing a process of the first embodiment.
4 is a cross-sectional view taken along the line BB in FIG.
FIG. 5 is a plan view showing a process of the first embodiment.
6 is a cross-sectional view taken along the line CC of FIG.
7 is a plan view showing a process of the first embodiment. FIG.
8 is a cross-sectional view taken along the line DD of FIG.
9 is a cross-sectional view taken along line EE in FIG.
10 is a cross-sectional view illustrating a light-emitting element of Embodiment 1. FIG.
FIG. 11 is a cross-sectional view of a main part showing Embodiment 2 of the method for manufacturing a light emitting element according to the present invention.
FIG. 12 is a cross-sectional view of a main part showing Embodiment 3 of the method for manufacturing a light emitting element according to the present invention.
FIG. 13 is a cross-sectional view illustrating a conventional light emitting element.
FIG. 14 is a plan view showing another conventional method for manufacturing a light-emitting element.
15 is a sectional view taken along line XX in FIG.
16 is a YY sectional view of FIG. 14;
FIG. 17 is a cross-sectional view of a main part showing problems of another conventional light emitting element.
[Explanation of symbols]
10 Light-Emitting Element 11 Glass Substrate 12 Front Electrode (One Electrode)
13 Interlayer insulating film 13A Opening 14 Resist layer 15 Organic EL layer 15A First organic film (predetermined organic film)
15B Second organic film (other organic film)
16 Back electrode material layer 16A Back electrode (the other electrode)

Claims (2)

In the method of manufacturing a light emitting device in which one electrode, an electroluminescent layer formed by laminating a plurality of films, and the other electrode are sequentially formed on a substrate,
After forming the one electrode, a separation layer is formed in which the side wall has an inversely tapered shape and the edge of the upper part of the pattern is located outside the planar region corresponding to each light emitting portion of the one electrode, and the electric field A predetermined film of a plurality of films constituting the light emitting layer is wet-formed on the entire surface of the substrate to form the electroluminescent layer, and then the material for forming the other electrode is formed using the separation layer as a mask. A manufacturing method of a light emitting element characterized by forming a film. Wherein the predetermined film, method of manufacturing the light emitting device according to claim 1, characterized in that soluble material in an organic solvent.

Images