JP2000113981A - Manufacture of organic el display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an organic EL display preventing erosion of an organic layer from a side wall and capable of increasing a display characteristic. SOLUTION: This manufacturing method of an organic EL display includes an electrode forming process for forming a first electrode 21 on a translucent substrate 20, a laminating process for forming and laminating an organic film 22a, a second electrode material film 23 and a protective film 24 in this order, a resist pattern forming process for forming a resist pattern on the protective film 24, and a patterning process for etching a laminated film constituted of an organic layer, a second electrode and the protective film 24 with the resist pattern used as a mask and forming the organic layer, the second electrode and a protective layer. The laminating process, the resist pattern forming process and the patterning process are repeated in sequence to form the organic layer in this manufacturing method. A side wall protective film forming process for forming a side wall protective film covering the side wall of the organic layer obtained in the previous patterning process is provided prior to the laminating process repeated after the patterning process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic EL (Electroluminescence) display having an organic electroluminescent device.

[0002]

2. Description of the Related Art An organic EL display comprising a large number of pixels composed of an organic electroluminescent device (hereinafter referred to as an organic EL device) is configured such that when a voltage is applied to the organic EL device, electrons are emitted from a cathode of the organic EL device. In addition, holes are injected from the anode into the organic light emitting layer, and light is generated by recombination of electrons and holes in the organic light emitting layer.

As an organic EL element provided in such an organic EL display, there is, for example, a single hetero organic EL element shown in FIG. This organic EL element is formed by indium tin oxide (ITO) on a transparent substrate 1 such as a glass substrate.
e) and the like, an anode 2 made of a transparent conductive film is provided, and an organic layer 5 made of a hole transport layer 3 and a light emitting layer 4 and a cathode 6 made of aluminum or the like are provided thereon in this order. Things.

[0004] Under such a configuration, the organic EL
In the device, when a positive voltage was applied to the anode 2 and a negative voltage was applied to the cathode 6, holes injected from the anode 2 were injected into the light emitting layer 4 via the hole transport layer 3 and from the cathode 6. The electrons reach the light emitting layer 4 respectively, and electron-hole recombination occurs in the light emitting layer 4. At this time, light having a predetermined wavelength is generated,
The light exits from the transparent substrate 1 side as shown by the arrow in FIG.

Therefore, by arranging a large number of such organic EL elements in a matrix, for example, an organic EL display is formed as described above. FIG.
FIG. 1 shows an example of such a conventional organic EL display. The organic EL display shown in FIG.
The transparent electrodes 8 in the form of stripes are provided thereon as anodes, and the organic layers 9a, 9b, 9c in the form of stripes comprising a hole transport layer and a light emitting layer are provided thereon in a state perpendicular to the transparent electrodes 8. , And these organic layers 9a, 9b, 9c
.. Have a stripe-shaped cathode 10 having substantially the same dimensions as the organic layers 9a (9b, 9c). Here, the organic layers 9a, 9b, and 9c have emission characteristics corresponding to one of red (R), green (G), and blue (B), respectively. It is a full-color or multi-color display.

An image display by such a color organic EL display will be described. In this color organic EL display, as shown in FIG.
1 is connected, and the luminance signal circuit 12 is connected to the cathode 10. The scanning circuit 11 and the luminance signal circuit 12 apply a signal voltage in a time series to the organic layers 9a to 9c at the intersections between the transparent electrode 8 and the cathode 10, so that the organic layers 9a to 9c emit light respectively. It has become. Therefore, by such control, the organic EL
The display also functions as an image reproducing device.

By the way, in order to manufacture the organic EL display shown in FIG. 5, conventionally, a plurality of stripe-shaped transparent electrodes 8 made of a transparent conductive film are formed on a transparent substrate 7 in parallel. For forming a transparent conductive film, a physical film forming method such as a sputtering method is often used. The processing of the transparent conductive film into a stripe shape is performed by a conventionally known lithography technique or etching technique.

After the formation of the transparent electrodes 8 in this manner, a plurality of organic layers 9a to 9c and a plurality of cathodes 10 are respectively formed so as to be substantially orthogonal to the transparent electrodes 8. The organic layers 9a to 9c and the cathodes 10 are formed by vacuum deposition through a mask having a stripe-shaped opening. Organic E shown in FIG.
In the case of a color display like the L display, for example, the organic layer 9a corresponding to red (R) and the cathode 10 thereon are deposited using the same mask, and then the mask is exchanged (or by moving the mask). 3) Organic layers 9b and 9c corresponding to green (G) and blue (B) and the cathode 10 thereon are formed in the same manner.

[0009]

However, in such a conventional manufacturing method, the organic layers 9a to 9c...
Since the mask vapor deposition method is used for forming the pattern of 0 ..., there are inconveniences described below. That is, the pattern formation by the mask vapor deposition method has a limitation in mask alignment accuracy and processing accuracy of the mask itself, and it is difficult to produce a fine pattern, so that it is difficult to produce a high-definition display.

As a method of manufacturing an organic EL display capable of forming a fine pattern with high accuracy in order to solve such a disadvantage, a technique disclosed in Japanese Patent Application Laid-Open No. 9-293589 is known. This method includes a film forming and laminating step of sequentially forming and stacking an organic film, a cathode material film, and a protective film on a transparent substrate on which an anode (transparent electrode) made of a transparent conductive material is formed; A resist pattern forming step of forming a resist pattern having a desired shape, and a laminated film including an organic film, a cathode material film, and a protective film is processed by a dry etching method using the resist pattern as a mask, and an organic layer having a desired shape, a cathode, And a patterning step of forming a protective layer. The step of applying a resist on the protective film and processing the laminated film by a dry etching method is repeated at least once so that a high-definition patterning of the organic layer and the cathode is performed. Is made possible.

However, even such a method has the following disadvantages. After performing the first film deposition and lamination step, the resist pattern formation step, and the patterning step on the transparent substrate on which the anode made of a transparent conductive film is formed, if these steps are repeated, the second and subsequent repetition steps In this state, the side wall of the organic layer of the organic EL element formed last time is exposed. Therefore, during the dry etching in the repetitive process, the exposed organic layer may be eroded from the exposed side wall. In addition, it is impossible to completely prevent such erosion from the exposed side wall of the organic layer even when reactive ion etching having excellent perpendicularity is used.

When the erosion from the side wall of the organic layer becomes severe, an undercut is formed from the side wall, and
As a result, a short circuit easily occurs between the cathode and the anode. In addition, even if the erosion is slight, the eroded area of the organic layer is reduced because the eroded portion does not emit light. Therefore, as the number of repetitions of the repetition step increases, the possibility that the organic layer formed first is almost eroded and light emission itself does not occur increases.

Accordingly, Japanese Patent Application Laid-Open No. 9-293589
The manufacturing method based on the technology disclosed in
The obtained organic EL display may have insufficient display characteristics and may not function sufficiently as a display. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing an organic EL display which can prevent erosion of an organic layer from a side wall and thereby enhance display characteristics. Is to do.

[0014]

According to the method of manufacturing an organic EL display of the present invention, an electrode forming step of forming a first electrode made of a transparent conductive material on a translucent substrate, and the first electrode is formed. A laminating step of sequentially laminating an organic film having a film made of at least an organic light emitting material, a second electrode material film and a protective film on the translucent substrate in this order; A resist pattern forming step of forming a resist pattern, and etching the laminated film including the organic film, the second electrode material film, and the protective film using the resist pattern as a mask, and forming an organic layer having a desired shape, a second electrode, A method of manufacturing an organic EL display, comprising: a patterning step of forming a protective layer, wherein the laminating step, the resist pattern forming step, and the patterning step are sequentially repeated to form an organic layer. Prior to the repetitive laminating step following the patterning step, prior to the repetitive laminating step, the method further comprises a side wall protective film forming step of forming a side wall protective film that covers at least the side wall of the organic layer obtained in the previous patterning step. The solution.

According to this manufacturing method, after the patterning step, prior to the repetitive laminating step, the side wall protective film covering at least the side wall of the organic layer obtained in the previous patterning step is formed. When the laminated film is etched in the above, the organic layer obtained earlier is hardly eroded by this etching because the side wall is covered and protected by the side wall protective film.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments. 1 (a) to 1 (e), 2 (a) to
(D) is a figure for demonstrating the manufacturing method of the organic EL display of this invention in order of a process. Especially, one embodiment of the case where this invention is applied to the manufacturing method of the full color organic EL display of a simple matrix system. FIG.

In this embodiment, first, as shown in FIG. 1A, a transparent substrate, that is, a transparent substrate 20 is prepared.
On the transparent substrate 20, a plurality of stripe-shaped transparent electrodes (first electrodes) 21 made of a transparent conductive material are formed in parallel. Here, the material of the transparent substrate 20 is not particularly limited, but is preferably excellent in light transmittance. In this example, a glass substrate is used. Further, as a material (transparent conductive material) of the transparent electrode 21 functioning as an anode, a material having excellent light transmittance and good electric conductivity is desirable. In this example, ITO is used. And, from such ITO, the transparent electrode 2
1 is formed on the transparent substrate 20 by a physical film forming method such as sputtering or the like.
The TO film is formed by patterning the TO film into a stripe by a lithography technique and an etching technique.

Next, as shown in FIG. 1B, an organic film 22a corresponding to red (R) is formed on the transparent substrate 20 in a state of covering the transparent electrodes 21 by vacuum evaporation. The organic film 22a is formed of a laminate having at least a hole transport layer, a light emitting layer made of an organic light emitting material, and an electron transport layer, and is formed to a thickness of about 100 nm in this example.

Subsequently, a cathode material (second electrode material) is formed on the organic film 22a, and a protective film 24 is formed on the cathode material film (second electrode material film) 23.
Then, the cathode material film 2 is formed on the organic film 22a.
3. The protective film 24 is deposited and laminated to form a laminated film 25.
Obtain a. Here, aluminum or an alloy thereof is suitably used as a cathode material, and in this example, aluminum is used. The protective layer 21 is preferably made of a material having excellent denseness, water repellency, and adhesion to the base and having electrical conductivity. In this example, a material containing phosphorus (P) as a high-concentration impurity is used. Crystalline silicon is used.

The cathode material film 23 is formed by a vacuum deposition method, and the protective layer 24 is formed by CVD having good coating characteristics.
Done by law. As a reactive gas of the CVD method, a mixed gas of monosilane, hydrogen, and phosphine is used. For forming the protective layer 24, a film forming method other than the CVD method such as a sputtering method can be adopted.

Next, a photoresist is applied on the protective film 24 to form a resist film having a thickness of about 1.0 μm, and the obtained resist film is patterned by exposing and developing the resist film, as shown in FIG. As shown in FIG. 7, a plurality of striped resist patterns 26 having a desired shape, that is, substantially perpendicular to the transparent electrodes 21 are formed in parallel.

Here, when aluminum or the like forming the cathode material film 23 is a thin film, pinholes are easily generated in the film. Therefore, such a cathode material film 23
When a photoresist is applied directly on the cathode material film 23,
In the case where even a small number of pinholes are present, the organic solvent in the photoresist passes through the pinholes and the organic film 22 is removed.
a, and erodes the organic film 22a. In this embodiment, since the cathode material film 23 is covered with the protective film 24 made of amorphous silicon in which pinholes are hardly generated, the organic film 22 made of the organic solvent as described above is used.
The erosion of a is prevented.

Next, using the resist pattern 26 as a mask, the laminated film 25a, ie, the protective film 24 made of amorphous silicon, the cathode material film 23 made of aluminum, and the organic film 22a are formed in this order by RIE (reactive ion etching). After etching and patterning, as shown in FIG. 1D, the protective layer 27, the cathode (second electrode) 28, and the organic layer 29 are formed.
a respectively. As an etching gas, a mixed gas of boron trichloride and chlorine is used for the protective film 24 made of amorphous silicon and the cathode material film 23 made of aluminum, and oxygen is used for the organic film 22a. Can be

By patterning in this manner, RI
Since the method E is anisotropic etching, the protective layer 27, the cathode 28, and the organic layer 29 having substantially the same dimensions as the resist pattern 26 are used.
a can be obtained. Here, the resist pattern 26
Is simultaneously removed when the organic film 22a (organic layer 29a) is etched. In addition, since the organic film 22a is extremely weak to oxygen, there is a possibility that the organic film 22a is slightly eroded during the etching from the side wall exposed by etching with oxygen plasma. However, by optimizing the etching conditions,
The effect can be minimized.

However, when such an etching step is repeated for forming the next green organic layer and then for forming the blue organic layer, the exposed side walls of the first formed red organic layer 29a are exposed to oxygen every time the etching step is performed. Because of exposure to the plasma, erosion by the oxygen plasma cannot be ignored. Therefore, in the present invention, in order to prevent such erosion by oxygen plasma, as described below, the organic layer 29 is formed.
a is covered with a side wall protective film.

Next, the protective layer 27, the cathode 28, the organic layer 29
A sidewall protection film (not shown) is formed so as to cover the entire laminate made of a, and is further patterned to cover the entire laminate as shown in FIG. A side wall protective layer 30a that covers the side wall 29a reliably is formed. The sidewall protective film 30a was formed by a CVD method using a mixed gas of ammonia, nitrogen, and monosilane, thereby forming a silicon nitride film having a thickness of about 100 nm. For patterning, a resist pattern (not shown) is formed on the silicon nitride film by photolithography, and using this resist pattern as a mask, RI using a mixed gas of carbon tetrafluoride and oxygen is used.
The etching was performed by the E method.

Next, in the same manner as the formation of the red organic layer 29a, this organic layer forming step is repeated to sequentially form a green organic layer 29b and a blue organic layer 29c. That is, first, as shown in FIG. 2A, an organic film 22b corresponding to green (G) is formed on the transparent substrate 20 by a vacuum evaporation method. Like the red organic film 22a, the green organic film 22b is also formed of a laminate having at least a hole transport layer, a light emitting layer made of an organic light emitting material, and an electron transport layer. It is formed to a thickness of about.

Subsequently, a cathode material (second electrode material) is formed on the organic film 22b, and a protective film 24 is formed on the cathode material film (second electrode material film) 23.
Then, as described above, the cathode material film 2 is formed on the organic film 22b.
3. The protective film 24 is formed and laminated to form a laminated film 25.
Obtain b. Further, a plurality of stripe-shaped resist patterns 26 are formed on the protective film 24 in parallel with each other in a state substantially orthogonal to the transparent electrodes 21.

Next, using the resist pattern 26 as a mask, the laminated film 25b, that is, the protective film 24, the cathode material film 2
3. RIE (reactive ion etching) of the organic film 22b
Etching and patterning in this order by the method shown in FIG.
As shown in (b), the protective layer 27, the cathode (second electrode) 2
8. An organic layer 29a is obtained. When etching is performed in this manner, the previously processed and formed organic layer 22a is formed.
Since its side wall is covered with the side wall protective film 30a, it is not eroded by oxygen plasma at the time of etching.

Next, the protective layer 27, the cathode 28, the organic layer 2
A side wall protective film (not shown) is formed in the same manner as in the previous case so as to cover the entire laminate made of 9b, and is further patterned to cover the entire laminate as shown in FIG. A side wall protective layer 30a that reliably covers the exposed side walls of the organic layer 29b is formed.

Next, similarly, as shown in FIG. 2D, a laminated body including the protective layer 27, the cathode 28, and the blue organic layer 29c is formed.
To form The blue organic layer 29c is also formed of a laminate having at least a hole transport layer, a light-emitting layer made of an organic light-emitting material, and an electron transport layer, like the red organic layer 29a and the green organic layer 29b. In this embodiment, the thickness is about 120 nm.

After that, the side wall protective film 30 covering each laminated body
a, 30b, and 30c are further covered with an insulating protective film (not shown) and the like to obtain a full-color organic EL display. The last organic layer, in this example, the blue organic layer 29
After the formation of the organic layer 29c, there is no step of processing and forming the organic layer thereafter.
The formation of c may be omitted.

In such a manufacturing method, after patterning the organic layer 29a (29b) having a desired shape, these steps are repeated before forming another organic layer 29b (29c) or the like. Side wall protective film 30a covering the side wall of organic layer 29a (29b) obtained in the step
Since (30b) is formed, when the laminated film 25b (25c) is etched in the repetitive patterning step, the side wall of the organic layer 29a (29b) obtained earlier is covered with the side wall protective film 30a (30b) for protection. As a result, erosion is not caused by this etching, and therefore, deterioration of display characteristics can be prevented.

In the embodiment, the transparent electrodes 21.
The organic layers 29a, 29b, 29c ... are provided directly on the
As shown in FIG. 3, these transparent electrodes 21.
a, 29b, 29c,..., an insulating layer 32 having an opening 31 may be provided. Here, the insulating layer 32 has an opening 31 on the transparent electrode 21, whereby the organic layer 29 a (29 b, 29 c) is directly connected to the transparent electrode 21 exposed in the opening 31. It comes into contact. If such an insulating layer 32 is provided, the transparent electrode 21 and the cathode 28 are surely insulated at locations other than the openings 31 of the insulating layer 32, so that the side wall protective layer 30a
As (30b, 30c), a material having electrical conductivity can be used.

In the above embodiment, the organic layer 29
Although the a, 29b, 29c and the cathode 28 are formed in a stripe shape, the present invention is not limited to this, and may have other shapes. For example, these organic layers 29a, 29c
The b, 29c and the cathode 28 may be formed in independent island patterns. Further, the transparent electrode 21 is not limited to the stripe shape, and various shapes (patterns) can be adopted.

The manufacturing method of the present invention can also be applied to a case where the organic layers 29a, 29b and 29c are formed in independent islands and are arranged for each unit pixel of the organic display. For example, the organic layers 29a, 29b, 29
If the plan view shape of c is a quadrangle, the side wall protective films 30a (30b, 30c) may be formed so as to cover the side walls of the organic layers 29a (29b, 29c) forming the respective sides. When making electrical contact with the cathode 28 on the organic layer 29a (29b, 29c), the side wall protective film 30a
On the upper surface of (30b, 30c), a through hole communicating with the cathode may be provided.

In the above-described embodiment, an example in which the organic EL display of the present invention is applied to a full-color type organic EL display has been described.
L display, and not only a simple matrix driven organic EL display but also TF
Active matrix organic EL by T drive
It is also applicable to displays.

Further, the organic EL display of the present invention comprises:
For example, it can be used as an optical element for a light source such as a dial, and in that case, an organic EL which becomes this optical element
It is not necessary to arrange the display in a matrix.
In addition, it can be applied to self-luminous elements such as filters for adjusting chromaticity and optical communication devices, and further to an image pickup element as an application when converting incident light into an electric signal. it can.

[0039]

As described above, according to the method of manufacturing an organic EL display of the present invention, after the patterning step, prior to the repeated laminating step, at least the side wall covering at least the side wall of the organic layer obtained in the previous patterning step. Since this is a method of forming a protective film, when the laminated film is etched in a repeated patterning step, the organic layer obtained earlier is eroded by this etching because its side wall is covered and protected by the side wall protective film. The display is hardly affected, so that the display characteristics can be prevented from deteriorating. Further, since the side wall protective film remains in a state of covering the side wall of the organic layer even after completion of all the manufacturing steps, the side wall protective film functions as a layer for protecting the organic layer from erosion from the air or the like. Organic EL
The life of the display can be extended.

[Brief description of the drawings]

FIGS. 1A to 1E are cross-sectional side views of a main part for describing an embodiment of a method for manufacturing an organic EL display according to the present invention in the order of steps.

FIGS. 2A to 2D are views for explaining an embodiment of a method for manufacturing an organic EL display of the present invention, and are for sequentially explaining steps following FIG. 1E. It is principal part sectional drawing.

FIG. 3 is a side sectional view of a main part for describing a modification of the manufacturing method of the present invention.

FIG. 4 is a side sectional view showing a schematic configuration of a conventional single hetero type organic EL element.

FIG. 5 is a perspective view showing a schematic configuration of an example of a conventional organic EL display.

6 is a perspective view showing a state where a driving circuit is connected to the organic EL display shown in FIG. 5;

[Explanation of symbols]

Reference numeral 20: transparent substrate, 21: transparent electrode, 22a, 22b: organic film, 23: cathode material film, 24: protective film, 25a, 25
b, 25c: laminated film, 26: resist pattern, 27:
Protective layer, 28: cathode, 29a, 29b, 29c: organic layer, 30a, 30b, 30c: sidewall protective film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsunobu Sekiya 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Naoki Sano 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Tetsuo Nakayama 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo F-term inside Sony Corporation (reference) 3K007 AB00 AB01 AB04 BA06 BB00 CA01 CB01 DA00 DB03 EB00 FA00 FA01 FA03

Claims (2)

[Claims] 1. An electrode forming step of forming a first electrode made of a transparent conductive material on a light-transmitting substrate, and a film made of at least an organic light-emitting material on the light-transmitting substrate on which the first electrode is formed. A laminating step of forming and laminating an organic film having a second electrode material film and a protective film in this order, a resist pattern forming step of forming a resist pattern having a desired shape on the protective film, A patterning step of etching a laminated film including an organic film, a second electrode material film, and a protective film as a mask to form an organic layer having a desired shape, a second electrode, and a protective layer; In a method for manufacturing an organic EL display in which an organic layer is formed by sequentially repeating a resist pattern forming step and a patterning step, prior to a subsequent laminating step following the patterning step , The method of manufacturing the organic EL display characterized by comprising a side wall protective film forming step of forming at least covers the side wall protective film side wall of the obtained organic layer in the previous patterning steps. 2. The method for manufacturing an organic EL display according to claim 1, wherein the sidewall protective film formed in the sidewall protective film forming step is formed of an inorganic insulating material.